bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology of Polymer/Clay Latex Particles Synthesized by Miniemulsion Polymerization: Modeling and Experimental Results
Authors: Mičušík Matej , Bonnefond Audrey , Reyes Yuri , Bogner Agnes , Chazeau Laurent , Plummer Christopher , Paulis Maria , Leiza Jose Ramon
Published: March 2010

BA/MMA (90:10 wt.‐%) were copolymerized in the presence of two different organomodified clays (C30B and CMA16) and 1.6–2.6 wbm.‐% surfactants. The effect of the compatibility of the organoclay in the monomer mixture on the morphology of hybrid polymer/clay particles was determined using TEM. The resulting morphologies were compared with the prediction of a Monte‐Carlo simulation that determined the equilibrium morphology of monomer/clay hybrid miniemulsion droplets. The model predicted encapsulated morphologies only when the organoclay presented low clay/monomer and high clay/water interfacial tensions. C30B and CMA16 did not fulfill these conditions and provided a preferential surface location of the platelets on the polymer/water interphase as predicted by the model.

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Life stories of people with rheumatoid arthritis who retired early: how gender and other contextual factors shaped their everyday activities, including paid work
Authors: Stamm T. A. , Machold K. P. , Smolen J. , Prodinger B.
Published: March 2010

Objective: The aim of the present study was to explore how contextual factors affect the everyday activities of women and men with rheumatoid arthritis (RA), as evident in their life stories.

Methods: Fifteen people with RA, who had retired early due to the disease, were interviewed up to three times, according to a narrative biographic interview style. The life stories of the participants, which were reconstructed from the biographical data and from the transcribed ‘told story’ were analysed from the perspective of contextual factors, including personal and environmental factors. The rigour and accuracy of the analysis were enhanced by reflexivity and peer‐review of the results.

Results: The life stories of the participants in this study reflected how contextual factors (such as gender, the healthcare system, the support of families and social and cultural values) shaped their everyday activities. In a society such as in Austria, which is based on traditional patriarchal values, men were presented with difficulties in developing a non‐paid‐work‐related role. For women, if paid work had to be given up, they were more likely to engage in alternative challenging activities which enabled them to develop reflective skills, which in turn contributed to a positive and enriching perspective on their life stories. Health professionals may thus use some of the women's strategies to help men.

Conclusion: Interventions by health professionals in people with RA may benefit from an approach sensitive to personal and environmental factors. Copyright © 2010 John Wiley & Sons, Ltd.
Characterizing the clinical practice and professional behaviour of rheumatology nurse specialists: a pilot study
Authors: Ryan Sarah , Hassell Andrew , Carpenter Elizabeth
Published: March 2010

Background: There is a need to characterize the practice of nurse specialists, for several reasons: to identify the skills and knowledge required for the role, to safeguard the role and to facilitate appropriate remuneration of activities.

Objective: To develop an instrument, which characterizes the clinical and professional activities of rheumatology nurse specialists (RNSs).

Methods: A questionnaire was produced, informed by the Nursing and Midwifery Council (NMC), to assess competencies in advanced nursing practice and completed by senior clinical rheumatology nurses in the UK undertaking an MSc in rheumatology nursing. Consenting respondents were also interviewed, to enable triangulation of the data.

Results: A 38‐item questionnaire was produced. It comprised four sections: clinical activities, non‐patient‐based activities, professional behaviour and perceived confidence in a number of areas of practice. Thirteen nurses completed the questionnaire and seven of these took part in a telephone interview. All RNSs were engaged in the follow‐up care of patients with rheumatoid arthritis, providing education, psychological support, monitoring and changing of drug treatments, and referrals to other health professionals. The RNSs produced guidelines, conducted audits and provided mentorship. They had low levels of confidence in seeing new patients, presenting the results of an audit at a conference, and writing a business case.

Conclusions: We have begun the process of developing a questionnaire that can identify the clinical activities, perceived self‐competence and professional behaviour of RNSs. This method of characterizing advanced nursing practice offers potential as a model for nurse specialists in other disciplines. Further work is required to validate the questionnaire on a large cohort of RNSs. Copyright © 2010 John Wiley & Sons, Ltd.
A literature review regarding the management of varicella‐zoster virus
Authors: Bond Deborah , Mooney Janice
Published: March 2010

Chickenpox and shingles (varicella‐zoster virus [VZV]) pose a threat to individuals who are immunosuppressed and/or have rheumatoid arthritis or another inflammatory musculoskeletal condition. In this paper we present a literature review of the condition, management and prevention. Copyright © 2010 John Wiley & Sons, Ltd.
Electron transport enhanced molecular dynamics for metals and semi‐metals
Authors: Jones Reese E. , Templeton Jeremy A. , Wagner Gregory J. , Olmsted David , Modine Nomand A.
Published: March 2010

In this work we extend classical molecular dynamics by coupling it with an electron transport model known as the two temperature model. This energy balance between free electrons and phonons was first proposed in 1956 by Kaganovet al. but has recently been utilized as a framework for coupling molecular dynamics to a continuum description of electron transport. Using finite element domain decomposition techniques from our previous work as a basis, we develop a coupling scheme that preserves energy and has local control of temperature and energy flux via a Gaussian isokinetic thermostat. Unlike the previous work on this subject, we employ an efficient, implicit time integrator for the fast electron transport which enables larger stable time steps than the explicit schemes commonly used. A number of example simulations are given that validate the method, including Joule heating of a copper nanowire and laser excitation of a suspended carbon nanotube with its ends embedded in a conducting substrate. Published in 2010 by John Wiley & Sons, Ltd.
A structural optimization method based on the level set method using a new geometry‐based re‐initialization scheme
Authors: Yamasaki Shintaro , Nishiwaki Shinji , Yamada Takayuki , Izui Kazuhiro , Yoshimura Masataka
Published: March 2010

Structural optimization methods based on the level set method are a new type of structural optimization method where the outlines of target structures can be implicitly represented using the level set function, and updated by solving the so‐called Hamilton–Jacobi equation based on a Eulerian coordinate system. These new methods can allow topological alterations, such as the number of holes, during the optimization process whereas the boundaries of the target structure are clearly defined. However, the re‐initialization scheme used when updating the level set function is a critical problem when seeking to obtain appropriately updated outlines of target structures. In this paper, we propose a new structural optimization method based on the level set method using a new geometry‐based re‐initialization scheme where both the numerical analysis used when solving the equilibrium equations and the updating process of the level set function are performed using the Finite Element Method. The stiffness maximization, eigenfrequency maximization, and eigenfrequency matching problems are considered as optimization problems. Several design examples are presented to confirm the usefulness of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.
The classical Hodgkin's lymphoma microenvironment and its role in promoting tumour growth and immune escape
Authors: Aldinucci Donatella , Gloghini Annunziata , Pinto Antonio , De Filippi Rosaria , Carbone Antonino
Published: March 2010

It has become clear that cancer is not merely a growth of autonomously proliferating cells, but that other non‐malignant cell types are a functional part of the disease. Immune cells, fibroblasts, specialized mesenchymal cells and microvasculature together make up the tumour microenvironment and have functional interactions with tumour cells. Classical Hodgkin's lymphoma (cHL) is characterized by only a few malignant cells and an abundance of inflammatory cells. Hodgkin and Reed–Sternberg (HRS) cells are surrounded by T and B cells admixed with plasma cells, macrophages, eosinophils and mast cells. A constitutive activity of NF‐κB and an altered JAK–STAT signalling pathway are part of the biological background associated with the increased expression of cytokines and cytokine receptors seen in HRS cells. Over‐expression of the members of the TNF receptor family, especially CD30 and CD40, is a hallmark of HRS cells. cHL is a tumour where aberrant cytokine production contributes not only to the proliferation of HRS cells but also to the maintenance of an appropriate environment for the tumour cells. In addition, several chemokines contribute to the composition of the inflammatory background in cHL. This review summarizes updated information on the complex interactions between the HRS cells and their tissue microenvironment and highlights the development of newer therapeutic strategies aimed at targeting the non‐malignant inflammatory/immune cellular components of HL that are involved in cancer cell growth and/or immune escape. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Intratumoural cytogenetic heterogeneity of sporadic colorectal carcinomas suggests several pathways to liver metastasis
Authors: Sayagués José María , del Mar Abad María , Melchor Hermann Barquero , Gutiérrez María Laura , González‐González María , Jensen Evan , Bengoechea Oscar , Fonseca Emilio , Orfao Alberto , Muñoz‐Bellvis Luís
Published: March 2010

Much has been learned about the chromosomal abnormalities of colorectal carcinomas but the cytogenetic relationship between the neoplastic clones present in primary versus metastatic tumour samples remains unclear. We analyse the frequency of abnormalities for 47 chromosome regions using the interphase fluorescence in situ hybridization technique in a group of 48 tumours, including 24 primary colorectal tumours and 24 paired liver metastases. All tumours showed complex karyotypes with numerical/structural abnormalities for seven or more different chromosomes/chromosome regions both in the primary tumours and in their paired metastases. Chromosome 8 was the most frequently altered (22/24 primary tumours), consistently showing del(8p22) and/or gains/amplification of 8q24, followed by abnormalities of the entire chromosome 7 (21/24 primary tumours) and of chromosomes 17p and 20q (20/24 primary tumours). Simultaneous staining for multiple chromosome probes revealed the presence of two or more tumour cell clones in 23/24 cases (46/48 tumour samples). Interestingly, the liver metastases typically contained tumour cell clones similar to those found in the primary tumours, suggesting the absence of selective selection of specific tumour clones. Despite this, additional chromosomal abnormalities were detected in 23/24 metastatic tumours, which preferentially consisted of del(17p13) and gains/amplification of 11q13 and 20q13; moreover, compared to primary tumours, metastases showed an increased number of abnormalities of chromosomes 1p, 7q, 8q, 13q, and 18q, and new chromosomal abnormalities involving chromosomes 6, 10q23, 14q32, 15q22, and 19q13. Owing to the high frequency of numerical abnormalities of the entire chromosome 7 and loss and/or gain/amplification of specific regions of chromosome 8, eg del(8p22) and/or gains/amplification of 8q24 in primary colorectal tumours with associated metastases, it is suggested that their assessment at diagnosis could be of great clinical utility for the identification of colorectal cancer patients at higher risk of developing liver metastases. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Load bearing properties of three‐component polymer composites
Authors: Ahmed Ahsan , Fahim Atef , Naguib Hani E.
Published: March 2010

Metal or solid polymer anchors are used as the load transfer components for foam and foam composites when they are used as the structural elements in design. The traditional method of fixation of these components is by fastening and adhesion. In this study, anchors were created in the form of inserts and were imbedded in the sandwich composite during the foaming process, resulting in the manufacture of three‐component composite. Flexure tests were conducted to study the effect of different geometries (rectangular, cylindrical, tapered/wedge shaped) and lengths of metal inserts on the strengths of sandwich composites. The stress strain response, mode of fracture of sandwich composite with metallic anchors was elucidated. The results showed that long tapered inserts imbedded in sandwich composite provide better load bearing and adhesion properties than other geometries. A model is presented that describes the relationship between stiffness reduction and progressive crack length of sandwich composite. Finite element analysis (FEA) of the interactions between the inserts and sandwich composites under different loads were carried out. FEA modeling and experimental results were in good agreement, thus validating the model. POLYM. COMPOS., 31:1731–1737, 2010. © 2010 Society of Plastics Engineers.
Electrochemically modified graphite nanosheets and their nanocomposite films with poly(vinyl alcohol)
Authors: Hu Huawen , Chen Guohua
Published: March 2010

A novel, facile, and environment friendly approach based on electrochemical oxidation and ultrasonication was presented to prepare electrically conductive graphite nanosheets (GNs). The as‐prepared GNs with a large aspect ratio were then incorporated into poly (vinyl alcohol) (PVA) by solution compounding. The GNs can be well and stably dispersed in water medium without the need for polymeric or surfactant stabilizers because of the electrochemical modification and their PVA nanocomposite films exhibit enhanced electrical, thermal, and mechanical properties compared with pure PVA film. Electrical resistivity decreases by 4 orders of magnitude with a percolation threshold of ca. 6 wt%. A significant improvement in thermal stability of 45°C and a large shift in glass transition temperature of 14°C are obtained, together with improved mechanical strength and toughness with the optimal GNs loading. POLYM. COMPOS., 31:1770–1775, 2010. © 2010 Society of Plastics Engineers.
Mandibular dimensions and growth in 11‐ to 26‐week‐old Danish fetuses studied by 3D ultrasound
Authors: Hermann Nuno V. , Darvann Tron A. , Sundberg Karin , Kreiborg Sven , Jørgensen Connie
Published: March 2010

Objective

To present normative data on prenatal mandibular morphology and growth.

Material and Methods

Fifty‐four normal fetuses (Danish Caucasian) were included in the study (gestational age: 11–26 weeks). Fetuses were scanned using a GE Voluson 730 Expert 3D scanner. Scans were visualized and analyzed using GE 4DVIEW™ software. Mandibular dimensions [base length (B), ramus height (H), and total length (L)] and the mandibular angle (φ) were measured, and the mandibular index was calculated. Method error was estimated by duplicate measurements. Growth was calculated by regressing measured variables on age.

Results

Mandibular measurements were found to be reliable [precision: 0.5–1.2 mm (1SD)]. Mean mandibular variable values at week 11: B = 5.2 ± 2.5 mm; H = 2.7 ± 1.3 mm; L = 7.7 ± 3.2 mm; φ = 149 ± 6.0°; and at week 26: B = 22.6 ± 2.5 mm; H = 12.3 ± 1.3 mm; L = 33.1 ± 3.2 mm; φ = 135 ± 6.0°. A linear model described growth (Bg/Hg/Lg/φg) giving Bg = 1.2; Hg = 0.64; L = 1.7 mm/week; φg = − 0.9°/week.

Conclusion

Normative 3D data values for the human mandible in 11‐ to 26‐week‐old fetuses were presented. All measured mandibular parameters could be described using a linear increasing model from 11 to 26 weeks. All linear dimensions increased in size, while the mandibular angle decreased steadily during the observation period. Copyright © 2010 John Wiley & Sons, Ltd.
Distributions of current and new first‐trimester Down syndrome screening markers in twin pregnancies
Authors: Koster M. P. H. , Wortelboer E. J. , Stoutenbeek Ph. , Visser G. H. A. , Schielen P. C. J. I.
Published: March 2010

Objectives

To study the distributions of pregnancy‐associated plasma protein A (PAPP‐A), the free β subunit of human chorion gonadotrophin (fβ‐hCG), A Disintegrin and Metalloprotease 12 (ADAM12) and Placental Protein 13 (PP13) in first trimester twin pregnancies.

Methods

Serum marker concentrations were measured in monochorionic and dichorionic twin pregnancies and singleton controls to study differences in multiples of the gestation‐specific normal medians (MoMs).

Results

Median PAPP‐A and fβ‐hCG MoMs were 2.03 and 1.87 for monochorionic twins (n = 116) and 2.18 and 1.89 for dichorionic twins (n = 650). Furthermore, ADAM12 and PP13 MoMs were 1.66 and 1.56 for monochorionic twins (n = 51) and 1.64 and 1.53 for dichorionic twins (n = 249). No statistically significant differences between monochorionic and dichorionic twin pregnancies were found. Correlations between markers in these pregnancies did not differ from singletons.

Conclusion

For first‐trimester screening, different parameters for monochorionic and dichorionic twin pregnancies is not necessary. Furthermore, if ADAM12 and PP13 will be adopted as screening markers, the presented median MoM values, standard deviations and correlation coefficients for twin pregnancies may contribute to a proper twin risk estimation. Copyright © 2010 John Wiley & Sons, Ltd.
The impact of rapid aneuploidy detection (RAD) in addition to karyotyping versus karyotyping on maternal quality of life
Authors: Boormans E. M. A , Birnie E. , Oepkes D. , Bilardo C. M. , Wildschut H. I. J. , Creemers J. , Bonsel G. J. , Lith J. M. M. van
Published: March 2010

Objective

To assess the impact of rapid aneuploidy detection (RAD) combined with fetal karyotyping versus karyotyping only on maternal anxiety and health‐related quality of life.

Methods

Women choosing to undergo amniocentesis were selected into group 1, i.e. receiving a karyotype result only (n = 132) or to group 2, i.e. receiving both the result of RAD and karyotyping (n = 181).

Results

There were no systematic differences in time of RAD combined with karyotyping versus karyotyping only in terms of anxiety (P = 0.91), generic physical health (P = 0.76, P = 0.46), generic mental health (P = 0.52, P = 0.72), personal perceived control (P = 0.91) and stress (P = 0.13). RAD combined with karyotyping reduced anxiety and stress two weeks earlier compared to karyotyping only.

Conclusion

RAD as add‐on to karyotyping reduces anxiety and stress in the short term but it does not influence overall anxiety, stress, personal perceived control, and generic mental and physical health when compared to a karyotype‐only strategy. Copyright © 2010 John Wiley & Sons, Ltd.
First trimester maternal serum placental growth factor in trisomy 21 pregnancies
Authors: Cowans N. J. , Stamatopoulou A. , Spencer K.
Published: March 2010

Objective

To examine placental growth factor (PlGF) levels in first trimester maternal serum in trisomy 21 pregnancies and to investigate the potential value of PlGF in a first trimester screening test.

Methods

First trimester maternal serum from 70 trisomy 21 cases and 375 euploid controls were retrospectively analyzed for PlGF using a DELFIA® Xpress immunoassay platform. Results were expressed as multiples of medians (MoM) for comparison.

Results

PlGF levels were significantly decreased in pregnancies with trisomy 21, 0.76 MoM versus 0.98 MoM in controls. Inclusion of PlGF into the first trimester combined test [maternal age, pregnancy associated plasma protein‐A (PAPP‐A), free‐β human chorionic gonadotrophin (β‐hCG) and nuchal translucency] would increase the detection rate by 0.5% at a 5% false positive rate.

Conclusion

PlGF at 11 weeks to 13 weeks 6 days has the potential to be included as a marker for the detection of pregnancies with trisomy 21. Copyright © 2010 John Wiley & Sons, Ltd.
Estimating the prevalence of inflammatory bowel disease in Portugal using a pharmaco‐epidemiological approach
Authors: Azevedo L. F. , Magro F. , Portela F. , Lago P. , Deus J. , Cotter J. , Cremers I. , Vieira A. , Peixe P. , Caldeira P. , Lopes H. , Gonçalves R. , Reis J. , Cravo M. , Barros L. , Ministro P. , Lurdes M. , Duarte A. , Campos M. , Carvalho L. , Costa‐Pereira A.
Published: March 2010

Purpose

To estimate inflammatory bowel disease (IBD) prevalence in Portugal from 2003 to 2007, and to obtain disease, sex and age specific estimates.

Methods

A pharmaco‐epidemiological approach based on intestinal anti‐inflammatory (IAI) drugs consumption was used. Proportion of patients taking IAI drugs and mean prescribed daily dose (PDD) were estimated from a sample of 513 IBD patients. Assumptions were made about unknown parameters and sensitivity analysis performed: drug compliance (80% in base case; range 70–85%) and proportion of sulphasalazine used in IBD (52%; range 40–80%). Sex and age specific estimates were based on a proposed methodological extension and results from a nationwide (n = 5893) cross‐sectional study.

Results

IBD prevalence increased from 86 patients per 100 000 in 2003 to 146 in 2007. Regions more affected were Lisboa and Porto (173 and 163 per 100 000 in 2007, respectively). Prevalence increased from 42 and 43 per 100 000 in 2003 to 71 and 73 in 2007, respectively for ulcerative colitis (UC) and Crohn's disease (CD). In 2007, prevalence was higher in the 40–64 age stratum for UC (99 per 100 000) and in the 17–39 stratum for CD (121). Prevalence was consistently higher in females.

Conclusions

Portugal is half way between countries with the highest and lowest IBD prevalence, but is steeply making the road to the highest‐level group. Despite limitations of the proposed methods, assumptions were reasonable and estimates seem to be valid. Feasibility and comparability of this methodology makes it an interesting tool for future studies on IBD epidemiology. Copyright © 2010 John Wiley & Sons, Ltd.
Laboratory monitoring and adverse patient outcomes with antihypertensive therapy in primary care
Authors: McDowell Sarah E. , Coleman Jamie J. , Evans Stephen J. W. , Gill Paramjit S. , Ferner R. E.
Published: March 2010

Purpose

The monitoring of serum electrolyte and creatinine concentrations in patients treated with antihypertensive therapy is recommended. We wished to examine the relationship between laboratory monitoring and adverse patient outcomes.

Methods

We carried out a retrospective cohort study using the General Practice Research Database (GPRD). Patients aged 18 years or older with newly diagnosed hypertension and prescribed a single antihypertensive agent were included. Monitoring was defined as any laboratory test for serum electrolyte and creatinine (or urea) concentrations within 6 months of starting treatment.

Results

We identified 74 096 patients who were newly diagnosed with hypertension and prescribed a single antihypertensive agent. Twenty six thousand nine hundred forty six (36.4%) patients had any biochemical laboratory measurement within 6 months. Three hundred ten patients (0.4%) died, 1451 (2%) were admitted to hospital at least once and 29 749 (40.2%) discontinued their first course of antihypertensive treatment within 6 months. Patients were more likely to be admitted to hospital if their biochemistry had been monitored after beginning treatment (adjusted hazard ratio (HR) 1.37; 95%CI 1.21–1.55). They were also marginally more likely to discontinue treatment (adjusted HR 1.04; 95%CI 1.02–1.07). They were not significantly more likely to die (adjusted HR 1.21; 95%CI 0.87–1.67).

Conclusions

Biochemical testing at baseline and monitoring after starting treatment is often omitted in newly diagnosed hypertensive patients. Those patients who are monitored are more likely to be admitted to hospital and to discontinue initial antihypertensive therapy, but not to die. Many biochemical adverse drug reactions are found only by laboratory monitoring. Copyright © 2010 John Wiley & Sons, Ltd.
Neuroleptic malignant syndrome and its controversies
Authors: Margetić Branimir , Margetić Branka Aukst
Published: March 2010

Purpose

Neuroleptic malignant syndrome (NMS) is a rare and life threatening condition usually defined as a complication of treatment with antipsychotics characterized by severe rigidity, tremor, fever, altered mental status, autonomic dysfunction, and elevated serum creatine phosphokinase and white blood cell count. The literature on this topic is rather extensive, but many aspects related to the syndrome are thought to be controversial. The aim of this paper, written with the clinician in mind, is to summarize some of the most prominent controversies that may have importance in usual clinical practice.

Methods

The literature was searched for reviews, reports on the series of cases, individual case reports of NMS, and other clinically and theoretically important information.

Results

There are controversies associated with virtually all important aspects of NMS. At the moment, it is not clear if this drug reaction is idiosyncratic or not, what diagnostic criteria are the most appropriate for usual clinical practice, and it seems that the estimated incidence is not in accordance with the number of treated patients. There are rather different approaches to the pathophysiological mechanisms, differential diagnosis, and treatment.

Conclusions

Some of the controversies related to NMS have an influence on our understanding of the condition and may have importance in clinical practice. There is a need for further research that should elucidate these controversies. Copyright © 2010 John Wiley & Sons, Ltd.
Preparation and characterization of high‐temperature resistance polyimide foams
Authors: Pan Ling‐Ying , Zhan Mao‐Sheng , Wang Kai
Published: March 2010

A new high‐temperature resistance polyimide foam was synthesized from 2,3,3′,4′‐biphenyltetracarboxylic dianhydride (α‐BPDA) and p‐phenylenediamine (p‐PDA). The structures and foaming process of polyimide precursor powders were characterized by wide‐angle X‐ray diffractometer (WXRD) and the self‐made visualization device, respectively. The imidization degree, thermal mechanical properties and thermal stability of the polyimide foams with different post‐treatment temperatures were also measured by fourier transform infrared spectrometer spectrum (FTIR), dynamic thermal mechanical anaylsis (DMTA), and thermogravimetric analysis (TGA). Results showed that the inflation onset temperatures of polyimide precursor powders ranged from 122 to 135°C with varying the heating rate. And the increase in the imidization degree, glass transition temperatures (Tg) and temperatures for 5 wt% mass loss of high‐temperature resistance polyimide foams can be achieved with increasing post‐treatment temperature. It was quite surprising to find that Tg of high‐temperature resistance polyimide foam post‐treated at 420°C was up to above 450°C, and the char yield at 800°C was more than 60%. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Gel‐spun polyacrylonitrile fiber from pregelled spinning solution
Authors: Tan Lianjiang , Liu Shuiping , Song Kunyang , Chen Huifang , Pan Ding
Published: March 2010

Polyacrylonitrile (PAN) fibers have been gel spun from pregelled PAN spinning solution. The pregelled solution had network structure with elevated spinnability, the as‐spun fiber from which had more circular cross‐section and reduced skin‐core difference. Drawing was more effective in inducing the segmental orientation and crystallization in gel‐spun fiber than in dry–wet spun fiber. The mechanical properties of the gel‐spun fiber were better than those of the dry–wet spun fiber after multi‐stage drawing. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Characterization of highly filled wood flour–polyvinyl chloride composites: Dynamic mechanical and dielectric analysis
Authors: Marathe D.S. , Joshi P.S.
Published: March 2010

Viscoelastic and dielectric properties of composites with polyvinyl chloride as major matrix constituent, ethylene vinyl acetate (EVA) as polymeric plasticizer, and wood flour (WF) and fly ash (FA) as filler have been studied. The effect of variation of WF, FA, and EVA on storage modulus E′, loss modulus E″, and glass transition temperature, Tg has been evaluated using dynamic mechanical analysis (DMA). Effect on permittivity ε′ and conductivity is evaluated using dielectric analysis. The results show considerable influence of constituents of the composite on the properties evaluated. DMA shows that WF contributes to an increase in Tg, E′, and E″ and a decrease in loss tangent, tan δ. The FA content has insignificant effect on these properties. Increasing WF content increases ε′. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Changes in lamellar arrangement of crystalline and flexible fluorinated transparent films with drawing
Authors: Fujimori Atsuhiro , Numakura Kazuya , Hayasaka Yuichiro
Published: March 2010

In recent times, a “crystalline” and flexible optical waveguide candidate with excellent heat‐resistance and dimensional stability are developed. For the practical use of this crystalline optical film in the near future, an accurate control of the solid‐state structure is indispensable because of the necessity of reducing light refraction at the crystalline/amorphous interface. In this study, changes in the fine structure and lamella arrangement upon drawing poly[tetrafluoroethylene‐co‐(perfluoroethylvinylether)] (EFA) transparent crystalline films were investigated by using wide‐angle X‐ray diffraction (WAXD) and small‐angle X‐ray scattering (SAXS) methods. The EFA was crystallized as a lamella crystal in the films and formed a thicker lamella. Upon the drawing of the EFA films, four‐point SAXS diagrams developed in the photograph at through direction to the film, which implied that a particular type of layer structure, an alternately tilted lamella arrangement known as the herringbone, was formed. From the result of WAXD and SAXS measurements at edge direction to the film, it is found that formation of isotropic disordered lamella arrangement. Therefore, it is indicated that three‐dimensional lamella arrangement in this fluorinated transparent film forms uniaxially cylindrical symmetry. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Morphology, microhardness, and flammability of compatibilized polyethylene/clay nanocomposites
Authors: Minkova L. , Peneva Y. , Valcheva M. , Filippi S. , Pracella M. , Anguillesi I. , Magagnini P.
Published: March 2010

Morphology, thermal properties, and microhardness of ethylene‐glycidyl methacrylate copolymer (EGMA)/clay and ethylene‐acrylic ester‐glycidyl methacrylate terpolymer (EAGMA)/clay nanocomposites with different clay concentrations have been studied. The results have shown that EGMA and EAGMA are highly compatible with the organoclays Cloisite®20A (Cl20A) and Cloisite®30B (Cl30B). Intercalated structures are formed in the whole range of Cl20A loadings investigated, whereas partial degradation of the Cl30B organoclay was observed. The thermal characteristics and microhardness of EGMA/clay nanocomposites suggest that the filler dispersion deteriorates at high concentration. The concentrated EGMA/Cl20A nanocomposites have been used as masterbatches to prepare ternary high density polyethylene (HDPE)/Cl20A and low density polyethylene (LDPE)/Cl20A nanocomposites. Diffractometric characterization and scanning electron microscopy observations of these materials have shown that the intercalated structure of the starting EGMA/Cl20A masterbatches is preserved after dilution with the polyolefins. The results suggest that the silicate platelets remain localized within the EGMA droplets in the diluted nanocomposites. The latter display improved microhardness, whereas the mechanical properties, including elongation at break, are comparable with those of the neat polyolefins. Considerable enhancement of the flame retardant properties has been observed for the ternary nanocomposites. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Rheological and mechanical characteristics of low density polyethylene/ethylene‐vinyl acetate/organoclay nanocomposites
Authors: Behradfar Afsoon , Shojaei Akbar , Sheikh Nasrin
Published: March 2010

Attempts were made to trace the effect of organoclay (OC) on the rheological and mechanical behaviors of the low density polyethylene (LDPE)/ethylene‐vinyl acetate (EVA) blends. To do this effectively, in addition to LDPE/EVA/OC system, pure LDPE and LDPE/EVA blends were also examined as model systems. The rheological behavior was determined by the capillary rheometer. Morphological characterization was also carried out using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and theoretical approach based on interfacial energies. Shear viscosity, tensile strength and elastic modulus of LDPE/EVA were found to decrease by increasing the EVA content, while for LDPE/EVA/OC ternary nanocomposites, such properties showed an increase by increasing the content of EVA. Such behavior was explained by the morphological characteristic of the system in which OC was mainly intercalated/exfoliated in the EVA phase. This morphological characteristic was corroborated by the XRD, TEM and interfacial energies data. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Optical monitoring of the injection molding of intercalated polypropylene nanocomposites
Authors: Moretti Fernando , Favaro Márcia M. , Branciforti Márcia C. , Bretas Rosario E.S.
Published: March 2010

Intercalated polypropylene (PP)/clay nanocomposites were produced by twin screw extrusion; afterwards, the optical monitoring of their injection molding was done using a laser sensor. The transmitted light intensity as a function of molding time was measured. The mold and melt temperatures, packing pressure and flow rate were changed. The nanocomposite had higher induction times than the PP, that is, scattering structures were detected later in the nanocomposite than in the PP, which was attributed to a retardation effect promoted by the clay on the PP crystallization growth rate. The morphologies of the injection molded samples were analyzed by polarized light optical microscopy, differential scanning calorimetry and transmission electron microscopy. The nanocomposite samples showed a second core, a thicker skin layer, highly oriented nanoclay's tactoids in the skin region and average spherulites' sizes smaller than the PP. The final light intensity If was correlated with the spherulites' sizes: high values of If represented samples with large spherulites. The PP sample had average spherulites' sizes larger than the Nano samples. However, the surging of a second core with large spherulites in the Nano samples changed the expected pattern: the PP samples showed If lower than the Nano samples. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Processing properties of polypropylene with a minor addition of silicone oil
Authors: Zhang Wei , Deodhar Sarang , Yao Donggang
Published: March 2010

Processing‐related properties of a polypropylene (PP)/silicone oil blend were investigated. It was found that an addition of a small amount (∼2 wt%) of silicone oil, a low molecular weight linear poly(dimethyl siloxane) (PDMS), drastically changed the rheological properties of PP. The PDMS seemed to work both as an internal lubricant and an external lubricant in the blend system. In particular, the apparent viscosity of the blend in capillary rheometry was approximately 10 times lower than that of virgin PP. The local minima in the viscosity versus shear rate curve in capillary rheometry and the gap‐dependency of viscosity in parallel‐plate rheometry implied the existence of a slip wall condition, caused by the formation of a thin lubricant layer at die walls. Thermal analyses and mechanical tests showed that the thermal and mechanical properties of the blend were nearly unaffected by the minor addition of silicone oil. The blend was tested in a profile extrusion process, and a significant reduction in die swell and profile distortion was achieved. The jet stretchability or spinnability in fiber spinning was also greatly improved with the minor addition of silicone oil. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Role of clay in compatibilization of immiscible high melt strength polypropylene and ethylene vinyl acetate copolymer blends
Authors: Bhattacharya Subhendu , Gupta Rahul K. , Bhattacharya Sati N.
Published: March 2010

The compatibilization efficiency of organically modified layered silicates (clay) was studied for immiscible high melt strength polypropylene/ethyl vinyl acetate (EVA) blends for the first time. The size of the dispersed EVA phase in the polypropylene matrix decreased with addition of small amounts of clay (cloisite 20A) to the blend. Scanning electron micrographs (SEM) show an efficient mixing of polymers in the presence of clay. The X‐ray diffraction (XRD) and transmission electron microscopy patterns demonstrate that silicate layers are well dispersed within the phases and are also present at the interphase. This results in substantial size reduction of the dispersed phase. The blends show a drastic increase in mechanical properties with the addition of clay. Differential scanning calorimetry thermo grams further help in understanding blend miscibility in the presence of clay as denoted by the change in the melting range of the components and the crystallization behavior of the components. The dynamic rheology tests reveal a emulsion‐like behavior for the blend system as denoted by the presence of a curvature or kink at lower frequencies, which further increases for the system with clay particles due to decrease in size of the dispersed phase. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Observation of instabilities in flow front during micro injection molding process
Authors: Kim Sun Kyoung , Choi Sung‐Ju , Lee Kwan‐Hee , Kim Dae‐Jin , Yoo Yeong‐Eun
Published: March 2010

This work has investigated filling characteristics during injection molding of a thin‐plate with microchannel patterns on it. To conduct molding experiments, an injection mold and mold inserts with microchannel patterns were designed and built. The experiments were conducted for three different channel sizes, and the results are analyzed. An unstable filling flow was observed in microscopic images for the smallest channel size. The front advanced with continuous creation and merge of microballs, which looked like teeth on the gum. We have analyzed this phenomenon and argued that there exists a critical channel width where such instability takes places. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Thermomechanical and barrier properties of UV‐cured epoxy/O‐montmorillonite nanocomposites
Authors: Peila Roberta , Malucelli Giulio , Lazzari Massimo , Priola Aldo
Published: March 2010

Mixtures of an epoxy resin and organophilic montmorillonites were subjected to ultraviolet (UV)‐induced photopolymerization. Two types of commercially available nanoclays, namely Cloisite 30B and Cloisite Na+, were modified through interaction with organic compatibilizers (dodecylsuccinic anhydride, octadecylamine, octadecyl alcohol, and octadecanoic acid). The modified nanoclays, dispersed in the liquid epoxy resin at 5 wt%, were photopolymerized to get nanocomposite films. The kinetics of the photopolymerization was evaluated by means of real‐time Fourier transform infrared spectroscopy. The modified nanoclays and their nanocomposites were characterized through X‐ray diffractometry; transmission electron microscopy showed the presence of intercalated and partially exfoliated morphologies in the nanocomposites. Thermogravimetric and dynamic‐mechanical analyses showed an increase of the thermal properties and an increase of the glass transition temperatures of the nanocomposites compared with that of the neat UV‐cured resin. Finally, the oxygen barrier properties of nanocomposite films, coated on a polyethyleneterephtalate substrate, were evaluated; the decrease of permeability was correlated with the degree of exfoliation of the nanocomposites. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Residual stresses in the quasi‐simultaneous laser transmission welding of amorphous thermoplastics
Authors: Bonefeld Dirk , Schöppner Volker , Potente Helmut , Mahnken Rolf , Shaban Ahmed
Published: March 2010

Laser transmission welding is frequently being used increasingly for joining complex, assembly‐oriented components, thanks to its small heat affected zone. As a result of the cooling processes, residual stresses can develop inside the components, potentially leading to stress cracking and premature component failure. One subgoal of process design should therefore be to reduce the level of residual stresses as far as possible when laser welding is employed. This work looks into experimental testing for residual stresses, as a factor for the weld parameters in quasi‐simultaneous laser transmission welding, with the objective of determining the optimum welding parameters. The ARAMIS optical measuring system for deformation analysis was used to this end, in conjunction with a modified hole‐drilling method. POLYM. ENG. SCI., 50:1520–1526, 2010. © 2010 Society of Plastics Engineers
Effect of glycerol on structure–property relations in chitosan/poly(ethylene oxide) blended films investigated using wide‐angle X‐ray diffraction
Authors: Jagadish Rampura S , Raj Baldev , Parameswara Puttanna , Somashekar Rudrappa
Published: March 2010

Polymer blending is an effective method for providing desirable polymeric materials with properties useful for the packaging industry. In the study reported, blends of chitosan/poly(ethylene oxide) (PEO) were prepared in various weight ratios with and without glycerol. Line profile analysis of the X‐ray diffraction patterns of these blended films was carried out. Microstructural parameters such as crystallite size and lattice strain were determined using paracrystalline modelling of X‐ray data. These values were correlated with physico‐mechanical and optical properties of the chitosan/PEO blends with and without glycerol to understand the holistic behaviour of the blends. Two prominent Bragg reflections at 2θ ≈ 19° and 23° were observed in the wide‐angle X‐ray diffraction patterns of the glycerol‐based chitosan/PEO blended films of various ratios. Interruption of PEO crystallization with chitosan results in an amorphous polymer network and hence a reduction in crystallite size by almost 97.7%. For glycerol‐based blends, the crystallite size/area decreases to 94.4% of the virgin crystallite size. The X‐ray profile analysis supports the results for the physico‐mechanical properties of the blends. The results show that the addition of 20 wt% of glycerol results in an increase of the elongation at break by more than 150%, meaning that these chitosan/PEO films could be applied in flexible packaging. Copyright © 2010 Society of Chemical Industry
The Role of Acidification for Antimicrobial Activity of Atmospheric Pressure Plasma in Liquids
Authors: Oehmigen K. , Hähnel M. , Brandenburg R. , Wilke Ch. , Weltmann K.‐D. , von Woedtke Th.
Published: March 2010

Water disinfection by indirect plasma treatment was investigated using a surface dielectric barrier discharge (DBD). Liquid was neither part of the discharge electrode configuration nor stirred during plasma treatment. High concentrations (106–108 cfu·mL−1) of Escherichia coli and Staphylococcus aureus have been completely inactivated within 5–15 min, depending on liquid sample volume. Inactivation occurred in non‐buffered liquids, only, where pH decrease was found. Measurements of pH, nitrate, and nitrite concentrations after DBD plasma or NO gas treatment lead to the conclusion that nitric acid formation from plasma‐generated reactive nitrogen species are the main source of liquid acidification. Incubation of bacteria in nitric acid alone did not result in comparable inactivation effects. Increase of H2O2 concentration was found as a result of plasma treatment of liquids but not after treatment by NO gas. Therefore, synergistic action of both reactive oxygen and nitrogen species are discussed to be responsible for antimicrobial plasma effects.

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pH‐sensitive properties of barium strontium titanate (BST) thin films prepared by pulsed laser deposition technique
Authors: Buniatyan Vahe V. , Abouzar Maryam H. , Martirosyan Norayr W. , Schubert Jürgen , Gevorgian Spartak , Schöning Michael J. , Poghossian Arshak
Published: March 2010

pH‐sensitive properties of barium strontium titanate (BST) high‐k thin films as alternative gate material for field‐effect capacitive (bio‐)chemical sensors based on an electrolyte‐insulator‐semiconductor system have been investigated. The BST films of different compositions (Ba0.31Sr0.69TiO3, Ba0.25Sr0.75TiO3and Mg‐doped Ba0.8Sr0.2Mg0.1Ti0.9O3) were deposited by pulsed laser deposition technique from targets fabricated by self‐propagating high‐temperature synthesis. The realised sensors have been electrochemically characterised by means of impedance‐spectroscopy, capacitance–voltage and constant‐capacitance method. The sensors possess a Nernstian‐like pH sensitivity in the concentration range between pH 3 and 11 with a response time of 5–10 s. An equivalent circuit model for the BST‐based capacitive field‐effect sensor is discussed.
Softlithographic partial integration of surface‐active nanoparticles in a PDMS matrix for microfluidic biodevices
Authors: Demming Stefanie , Hahn Anne , Edlich Astrid , Franco‐Lara Ezequiel , Krull Rainer , Barcikowski Stephan , Büttgenbach Stephanus
Published: March 2010

The mergence of microfluidics and nanocomposite materials and their in situ structuring leads to a higher integration level within microsystems technology. Nanoparticles (Cu and Ag) produced via laser radiation were suspended in Poly(dimethylsiloxane) to permanently modify surface material. A microstructuring process was implemented which allows the incorporation of these nanomaterials globally or partially at defined locations within a microbioreactor (MBR) for the determination of their antiseptic and toxic effects on the growth of biomass.

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Partially structured PDMS with nanoparticle–PDMS composite.
Surface chemistry and topographical changes of an electropolished NiTi shape memory alloy
Authors: Neelakantan Lakshman , Valtiner Markus , Eggeler Gunther , Hassel Achim Walter
Published: March 2010

Electropolishing and its mechanism for NiTi shape memory alloy in methanolic sulfuric acid have been investigated recently. In the current study, X‐ray photoelectron spectroscopy was carried out to characterize the chemical nature of the electropolished surface. The electropolished surface is covered by a thin layer of TiO2. For an electropolished specimen, the Ni:Ti ratio at surface (∼1 nm) was 0.31, whereas for a mechanically polished specimen the ratio was 0.70. The second aspect of this work is the attempt to characterize the salt film formed during electropolishing. The characterization of salt‐film showed sulfide and sulfate compounds of Ni and/or Ti. The crystallographic and topographical changes caused due to thermally induced phase transformation on an electropolished NiTi was followed by in situ XRD and AFM. AFM studies revealed significant changes in the surface features due to phase transformation. The surface roughness value increased by a factor of 2.