bluuebunny/crossref_metadata_2025 huggingface dataset:
Conduction velocity distribution in neurologically well‐recovered but fatigued Guillain–Barré syndrome patients
Authors: Garssen Marcel P. J. , Blok Joleen H. , van Doorn Pieter A. , Visser Gerhard H.
Published: November 2005

Many patients with Guillain–Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) suffer from excessive fatigue. To assess whether this fatigue might be related to changes in slow‐conducting nerve fibers, we determined the conduction velocity distribution (CVD) in the median nerve. Thirteen fatigued but neurologically well‐recovered GBS patients, 2 fatigued and stable CIDP patients, and 19 healthy controls participated in this study. Conventional maximal nerve conduction velocities (NCVs) did not show differences between GBS patients and healthy controls. However, in both GBS and CIDP patients the CVD was altered, showing significant narrowing of the velocity distribution with loss of the fastest‐ and slowest‐conducting fibers. These changes were most pronounced in the subgroup of patients with the lowest fatigue scores. We therefore conclude that the observed CVD changes in patients are not likely to contribute to persisting complaints of fatigue after GBS. Muscle Nerve 2006
Effects of changing wrist positions on finger flexor hypertonia in stroke survivors
Authors: Li Sheng , Kamper Derek G. , Rymer William Zev
Published: November 2005

We sought to establish whether spastic hypertonia results from changes in intrinsic muscle properties or from altered stretch reflex properties. We hypothesized that finger flexor spastic hypertonia is primarily of neural origin, and that the dynamics of spastic muscle responses to stretch should therefore reflect the dynamics of muscle spindle receptor responses. In 12 stroke survivors, we recorded torque and electromyographic (EMG) responses of extrinsic finger flexors to constant‐velocity rotation of the metacarpophalangeal (MCP) joints of the affected hand, over a range of initial muscle lengths. Stretch velocity was set to 6°, 50°, 150°, or 300° per second. Muscle length changes were imposed by changing wrist angle between 0°, 25°, and 50° of flexion. We found that reflex torque and EMG responses exhibited both velocity and length dependence, and there were significant interactions between velocity and length, replicating known characteristics of muscle spindle receptors. Our results support the hypothesis that finger flexor hypertonia is primarily of neural origin, and that it accurately reflects spindle receptor firing properties. Muscle Nerve 2006
Electromyographic studies in mdx and wild‐type C57 mice
Authors: Han Jay J. , Carter Gregory T. , Ra Jennifer J. , Abresch R. Ted , Chamberlain Jeffrey S. , Robinson Lawrence R.
Published: November 2005

The electromyographic (EMG) characteristics of human Duchenne muscular dystrophy (DMD) have been well‐described. However, to our knowledge, no prior needle electromyographic (EMG) studies of motor unit morphology have been undertaken in muscles from the mdx mouse, an animal that is genetically homologous to DMD. There are significant phenotypic differences between the human and murine dystrophic conditions, bringing into question whether the mdx mouse is an appropriate animal model for DMD. This study was done in order to characterize the EMG findings in mdx mice, compared to normal wild‐type mice, and to assess for similarities to DMD. The tibialis anterior and gastrocnemius/soleus muscles from 34 mice (16 C57 wild‐type and 18 mdx), divided into four age groups (3, 12, 18, and 24 months), were examined. Wild‐type muscles showed normal insertional activity and no abnormal activity at rest. Motor unit action potential (MUAP) parameters were characterized. In contrast to wild‐type muscles, mdx muscles showed increased insertional activity, abnormal spontaneous potentials, and the presence of complex repetitive discharges (CRDs). MUAPs showed increased numbers of phases (4.0 ± 0.6, P < 0.001) and duration (7.1 ± 1.2 ms, P < 0.02), as well as late components (15%). These EMG data indicate that mdx muscles display EMG characteristics similar to those found in muscles from boys with DMD, lending credence to the mdx mouse as an animal model for this disease. The data obtained in this study indicate a potential role for EMG as an in vivo, objective measurement tool that could be used longitudinally to monitor the effects of therapeutic interventions in mdx mice. This is important as there are few objective measures of muscle function in murine models that do not require killing the animal. Muscle Nerve, 2006
Short‐ or long‐term effects of adult myoblast transfer on properties of reinnervated skeletal muscles
Authors: Coulet Bertrand , Lacombe Fabien , Lazerges Cyril , Daussin Paul‐André , Rossano Bernadette , Micallef Jean‐Paul , Chammas Michel , Reyne Yves , Bacou Francis
Published: November 2005

Skeletal muscle demonstrates a force deficit after repair of injured peripheral nerves. Data from the literature indicate that myoblast transfer enhances recovery of muscle function. Thus, we tested the hypothesis that transfer of adult myoblasts improves the properties of reinnervated rabbit tibialis anterior (TA) muscles in both the short term (4 months) and long term (14 months). Two months after transection and immediate suture of the common peroneal nerve, TA muscles were made to degenerate by cardiotoxin injection and then transplanted with adult myoblasts cultured for 13 days. Under these conditions, muscles studied at 4 months were heavier, contained larger fibers, and developed a significantly higher maximal force than muscles that had only been denervated–reinnervated. In the long term, although muscles made to degenerate were heavier and developed a significantly higher maximal force than denervated–reinnervated muscles, myoblast transfer failed to improve these parameters. However, the overall characteristics of long‐term operated muscles tended clearly to approach those of the controls. Taken together, these results may have significant implications in certain orthopedic contexts, particularly after immediate or delayed muscle reinnervation. Muscle Nerve, 2006
MLS‐based variable‐node elements compatible with quadratic interpolation. Part II: application for finite crack element
Authors: Cho Young‐Sam , Im Seyoung
Published: November 2005

Two‐dimensional finite ‘crack’ elements for simulation of propagating cracks are developed using the moving least‐square (MLS) approximation. The mapping from the parental domain to the physical element domain is implicitly obtained from MLS approximation, with the shape functions and their derivatives calculated and saved only at the numerical integration points. The MLS‐based variable‐node elements are extended to construct the crack elements, which allow the discontinuity of crack faces and the crack‐tip singularity. The accuracy of the crack elements is checked by calculating the stress intensity factor under mode I loading. The crack elements turn out to be very efficient and accurate for simulating crack propagations, only with the minimal amount of element adjustment and node addition as the crack tip moves. Numerical results and comparison to the results from other works demonstrate the effectiveness and accuracy of the present scheme for the crack elements. Copyright © 2005 John Wiley & Sons, Ltd.
Two implementations of IRK integrators for real‐time multibody dynamics
Authors: Dopico D. , Lugris U. , Gonzalez M. , Cuadrado J.
Published: November 2005

Recently, several authors have proposed the use of implicit Runge–Kutta (IRK) integrators for the dynamics of multibody systems. On the other hand, Newmark‐type or structural integrators have shown to be appropriate when real‐time performance is demanded in that field. Therefore, the following question arises: might the IRK integrators be suitable for real‐time purposes? And, provided the answer is positive: might they be preferable to the Newmark‐type family?

This paper reports an investigation which has been conducted by the authors in order to get insight into the two questions formulated above. Since, based on previous experiences, it can be suspected that the performance of the integrators may be dependent on the type of dynamic formulation applied, the following three formulations have been considered for the study: a global penalty formulation in dependent natural co‐ordinates (many constraints), a topological semi‐recursive penalty formulation in dependent relative co‐ordinates (few constraints), and a topological semi‐recursive formulation in independent relative co‐ordinates (no constraints).

As representative of the IRK family, a two‐stage SDIRK integrator has been selected due to its low associated computational burden, while, on the side of the structural integrators, the trapezoidal rule has been chosen. Two alternative implementations have been proposed to combine the dynamic formulations and the SDIRK integrator.

A very demanding maneuver of the whole model of a vehicle has been simulated through all the possible combinations dynamic‐formulation/integrator, for different time‐steps. Conclusions have been drawn based on the obtained results, which provide some practical criteria for those interested in achieving real‐time performance for large and complex multibody systems. Copyright © 2005 John Wiley & Sons, Ltd.
The development of hybrid axisymmetric elements based on the Hellinger–Reissner variational principle
Authors: Jog C. S. , Annabattula R.
Published: November 2005

We present a general procedure for the development of hybrid axisymmetric elements based on the Hellinger–Reissner principle within the context of linear elasticity. Similar to planar elements, the stress interpolation is obtained by an identification of the zero‐energy modes. We illustrate our procedure by designing a lower‐order (four‐node) and a higher‐order (nine‐node) element. Both elements are of correct rank, and moreover use the minimum number of stress parameters, namely seven and 17. Several examples are presented to show the excellent performance of both elements under various demanding situations such as when the material is almost incompressible, when the thickness to radius ratio is very small, etc. When the variation of the field variables is along the radial direction alone, when the mesh is uniform, and the loading is of pressure type, the developed elements are superconvergent, i.e. they yield the exact nodal displacement values. Copyright © 2005 John Wiley & Sons, Ltd.
Study on superabsorbent composite. V. Synthesis, swelling behaviors and application of poly(acrylic acid‐co‐acrylamide)/sodium humate/attapulgite superabsorbent composite
Authors: Zhang Jun Ping , Li An , Wang Ai Qin
Published: November 2005

A novel multifunctional superabsorbent composite from acrylic acid (AA), acrylamide (AM), sodium humate (SH) and attapulgite (APT), PAA‐AM/SH/APT, was synthesized by aqueous solution polymerization, using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator. In this paper, not only the effects of the ratio of AA to AM, SH and APT content on the saturated water absorbency, but also various swelling behaviors of the composite were systematically investigated. The results show that comprehensive performances of the superabsorbent are improved by introducing functional components into a poly(acrylic acid‐acrylamide) (PAA‐AM) network. Functionality of the composite in practice was also investigated by studying the release of SH and by growing Elymus dahuricus Turcz (a kind of grass) plants in soil with and without using the superabsorbent composite. The roots and stems of Elymus dahuricus Turcz were found to be sturdier compared with the plants grown without the superabsorbent composite. Copyright © 2005 John Wiley & Sons, Ltd.
Germ cell lineage differentiation in non‐seminomatous germ cell tumours
Authors: Honecker Friedemann , Stoop Hans , Mayer Frank , Bokemeyer Carsten , Castrillon Diego H , Lau Yun‐Fai Chris , Looijenga Leendert H J , Oosterhuis J Wolter
Published: November 2005

Human germ cell tumours (GCTs) have long fascinated investigators for a number of reasons. Being pluripotential tumours, they can differentiate into both extra‐embryonic and embryonic (somatic) tissues. However, it has never been shown convincingly that, in humans, these tumours are truly totipotent and can also give rise to the germ lineage, the third major differentiation lineage occurring early during embryonic life. Using a number of newly available, distinct, immunohistochemical markers, such as OCT3/4, VASA and TSPY, the occurrence of germ cells was investigated in a number of germ cell tumours. Development of germ cells was identified in three independent non‐seminomas, including two pure yolk sac tumours and one mixed tumour composed of yolk sac tumour and immature teratoma. Our finding indicates a previously unknown totipotent potential of human GCTs and raises the question of whether, under certain culture conditions, primordial germ cells could be derived from human GCT cell lines. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Iron‐free neoplastic nodules and hepatocellular carcinoma without cirrhosis in Wistar rats fed a diet high in iron
Authors: Asare George A , Paterson Alan C , Kew Michael C , Khan Shehnaz , Mossanda Kensese S
Published: November 2005

Although excess hepatic iron in hereditary haemochromatosis and dietary iron overload in the African causes hepatocellular carcinoma, it usually does so in the presence of cirrhosis. A direct hepatocarcinogenic effect of iron has not been proved. Moreover, an animal model of hepatocellular carcinoma induced by iron overload has not been available. The aim of this study was to develop such a model and to use it to ascertain whether excess hepatic iron is directly hepatocarcinogenic. Sixty Wistar albino rats were fed a chow diet and 60 the same diet supplemented initially with 2% carbonyl iron for 12 months, followed by 0.5% ferrocene for 20 months. Five rats from each group were sacrificed every 4 months for 24 months for histological and biochemical monitoring. By 16 months, hepatocytes in all the rats receiving the iron‐supplemented diet showed grade 4 iron overload, comparable in degree with that seen in patients with advanced hereditary haemochromatosis and dietary iron overload. Altered hepatic foci and pre‐neoplastic nodules were first seen at 16 months. These increased in size and number with time, were iron‐free, stained positively with placental glutathione sulphydryl transferase, and showed the same histological features as the iron‐free foci described in patients with hepatocellular carcinoma complicating hereditary haemochromatosis. At 32 months the eight surviving rats in the iron overloaded group were sacrificed. The livers of five of these rats contained pre‐neoplastic nodules and one showed, in addition, an iron‐free, well‐differentiated hepatocellular carcinoma. The tumour stained positively for placental glutathione sulphydryl transferase. Neither cirrhosis nor portal fibrosis was present in this or any iron‐loaded animal. We conclude that hepatocellular carcinoma may complicate dietary hepatic iron overload in Wistar albino rats in the absence of fibrosis or cirrhosis, confirming an aetiological association between dietary iron overload and the tumour and suggesting that iron may be directly hepatocarcinogenic. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Role of metalloproteinases MMP‐9 and MT1‐MMP in CXCL12‐promoted myeloma cell invasion across basement membranes
Authors: Parmo‐Cabañas Marisa , Molina‐Ortiz Isabel , Matías‐Román Salomón , García‐Bernal David , Carvajal‐Vergara Xonia , Valle Inmaculada , Pandiella Atanasio , Arroyo Alicia G , Teixidó Joaquin
Published: November 2005

Malignant plasma cells in multiple myeloma home to the bone marrow (BM), accumulate in different niches and, in late disease, migrate from the BM into blood. These migratory events involve cell trafficking across extracellular matrix (ECM)‐rich basement membranes and interstitial tissues. Metalloproteinases (MMP) degrade ECM and facilitate tumour cell invasion. The chemokine CXCL12 is expressed in the BM, and it was previously shown that it triggers myeloma cell migration and activation. In the present work we show that CXCL12 promotes myeloma cell invasion across Matrigel‐reconstituted basement membranes and type I collagen gels. MMP‐9 activity was required for invasion through Matrigel towards CXCL12, whereas TIMP‐1, a MMP‐9 inhibitor that we found to be expressed by myeloma and BM stromal cells, impaired the invasion. In addition, we show that the membrane‐bound MT1‐MMP metalloproteinase is expressed by myeloma cells and contributes to CXCL12‐promoted myeloma cell invasion across Matrigel. Increase in MT1‐MMP expression, as well as induction of its membrane polarization by CXCL12 in myeloma cells, might represent potential mechanisms contributing to this invasion. CXCL12‐promoted invasion across type I collagen involved metalloproteinases different from MT1‐MMP. These data indicate that CXCL12 could contribute to myeloma cell trafficking in the BM involving MMP‐9 and MT1‐MMP activities. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Methylation of APC, TIMP3, and TERT: a new predictive marker to distinguish Barrett's oesophagus patients at risk for malignant transformation
Authors: Clément Geneviève , Braunschweig Richard , Pasquier Nathalie , Bosman Fred T , Benhattar Jean
Published: November 2005

Barrett's associated oesophageal adenocarcinoma (EAC) is one of the most rapidly increasing malignancies in Western countries. Because of its poor prognosis, management of this disease through screening of Barrett's oesophagus (BE) patients and identification of those with a high risk of developing an adenocarcinoma seems a promising approach. Early molecular markers of malignant transformation might contribute to such screening approaches. Gene promoter methylation analysis was performed on normal, pre‐neoplastic, and neoplastic lesions from BE patients. All lesions of interest were sampled by microdissection from formalin‐fixed paraffin‐embedded tissue sections. We found that, in 27 adenocarcinomas, APC, TIMP3, TERT, CDKN2A, and SFRP1 promoters were methylated in 93%, 65%, 64%, 48%, and 91%, respectively; in contrast MLH1, RASSF1, RARB, CDH1, and FHIT promoters were methylated in less than 5% of the tumours. In BE mucosa from patients who had progressed to adenocarcinoma (12 samples), APC, TIMP3, and TERT promoters were hypermethylated in 100%, 91%, and 92% of cases, whereas in BE mucosa from patients who had not progressed (16 samples) methylation was found only in 36%, 23%, and 17%, respectively. Furthermore, the epigenetic profile of BE with and without EAC differed significantly with, respectively, 81% and 26% of the PCR samples showing promoter hypermethylation for APC, TIMP3, and TERT (p < 0.0001). Promoter methylation of CDKN2A was infrequently detected in BE samples, while SFRP1 methylation was observed in all samples. Our results suggest that promoter methylation profiling of BE using multiple target genes including APC, TIMP3, and TERT might be used as a predictive marker for increased EAC risk. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Career choices for pathology: national surveys of graduates of 1974–2002 from UK medical schools
Authors: Lambert Trevor W , Goldacre Michael J , Turner Gill , Domizio Paola , du Boulay Clair
Published: November 2005

In the past 10 years there has been increasing concern about recruitment of junior doctors into pathology, particularly histopathology, in the UK. In this study, we report on career choices for pathology, derived from postal questionnaire surveys of all qualifiers from all UK medical schools in nine qualification years since 1974. 74% (24 623/33 417) and 73% (20 709/28 468) of doctors responded at 1 and 3 years after qualification. The percentage of doctors choosing pathology 1 year after qualification has fallen sharply in recent years: between 1974 and 1983 it was 4.5% (95% confidence interval 4.1–4.9%) and between 1993 and 2002 it was 2.3% (CI 2.0–2.5%). 57% of doctors who chose pathology 1 year after qualification were still working in pathology at year 10. Hours and conditions of work, the doctor's personal assessment of their aptitudes, and their experience of the subject as a student influenced long‐term career choices for pathology. Recruitment of UK graduates into the pathology specialties must increase to meet demand in the new and expanding subspecialties. This depends on developing innovative ways of raising the profile of pathology to medical students and junior hospital doctors. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Analysis of needle versus open biopsy for the diagnosis of advanced stage pediatric neuroblastoma
Authors: Gupta Abha , Kumar Ashesh , Walters Sarah , Chait Peter , Irwin Meredith S. , Gerstle J. Ted
Published: November 2005

Background

Adequate tissue biopsy is necessary for the appropriate diagnosis and risk stratification of pediatric neuroblastoma (NB). We compared the quality and adequacy of biopsy tissue and complication rates in children with NB who underwent open (OBX) and image‐guided needle biopsy (NBX) at our center.

Methods

We retrospectively reviewed all patients diagnosed with stage III and IV NB from September 2001 to August 2004. The 24 patients were divided into two groups: those in whom the diagnosis was initiated using NBX, and those diagnosed using OBX. In addition to demographic data, we collected data pertaining to sufficiency of biopsy tissue for biology studies including: Shimada Classification, MYC‐N amplification, and DNA index analysis and complications associated with the procedure. Chi‐Square and Student's t‐test were used to analyze the categorical and continuous variables, respectively.

Results

Of 24 patients, 11 underwent NBX, and 13 patients underwent OBX. Eighteen patients had stage IV disease, 5 patients had stage III disease, and 1 stage IVS. Ten major complications occurred in four NBX patients and six OBX patients. There was no difference in days of narcotic use, time to DAT, or hospital stay between the two groups. Ten patients (seven NBX and three OBX, P = 0.045) had tissue that was insufficient for biology studies. Three of the seven NBX patients underwent a second biopsy for clarification of risk group.

Conclusions

This study demonstrated that more than half of patients undergoing NBX for NB had insufficient tissue for complete histological and molecular classification and that the incidence of procedural complications between NBX and OBX are similar. © 2005 Wiley‐Liss, Inc.
Experiences of people with type 2 diabetes who have changed from oral medication to self‐administered insulin injections
Authors: Morris JE , Povey RC , Street CG
Published: November 2005

It has been estimated that the majority of patients with type 2 diabetes mellitus will need treatment with insulin eventually if they are to keep their blood sugar levels within recommended limits. Whilst much is known about the physiological benefits of insulin, far less is known about the ‘lived experience’ of going onto insulin therapy. The purpose of this study was to elucidate the range of subjective experiences of men and women with type 2 diabetes who have recently gone onto insulin. It was specifically concerned with their expectations and experiences of insulin and the impact they felt it made on their lives.

A purposeful sample of six people with type 2 diabetes mellitus, who had recently commenced on insulin therapy, was taken. Data were collected using semi‐structured interviews which were audiotape‐recorded and transcribed. The transcripts were analysed together with the researcher's observational notes and documentary evidence, using interpretive phenomenological analysis.

The data showed that patients experienced a range of initial reactions (from shock and anger, to relief) and perceptions of insulin, sometimes resulting in an altered self‐image. However, perceptions were shown to change over time, with some patients eventually accepting insulin and becoming empowered.

It was concluded that patients starting on insulin need a programme of education and support which is not solely directed at imparting knowledge and new skills. Health care professionals must first establish patients' health beliefs, expectations and fears regarding insulin, if this knowledge is to be accepted and new skills are to be used effectively. Copyright © 2005 John Wiley & Sons, Ltd.
Polycystic ovary syndrome
Authors: Kar PS , Cummings MH
Published: November 2005

Polycystic ovary syndrome (PCOS) is a diagnosis made in women between late adolescence and the menopause. Patients may present with menstrual irregularity, features of hyperandrogenism (hirsuitism, acne) or infertility. Diagnosis of PCOS is made on clinical features, abnormal biochemistry adjunct and/or ultrasound ovaries.

PCOS is also associated with insulin resistance with consequent hyperinsulinaemia, hyperlipidaemia and obesity. Efforts to reduce insulin resistance and hyperinsulinaemia such as weight reduction and insulin sensitisers have been beneficial and form an important management strategy for some aspects of the syndrome. Other measures include treatment directed at specific clinical features, such as hirsuitism, menstrual irregularities and infertility.

Due to the present evidence suggesting a link with insulin resistance and increased cardiovascular risk, patient education and attention to diabetes and cardiovascular risk factors need to be addressed. Copyright © 2005 John Wiley & Sons, Ltd.
Metabolic and cardiovascular risk in the polycystic ovary syndrome
Authors: Cussons AJ , Stuckey BGA , Watts GF
Published: November 2005

The polycystic ovary syndrome (PCOS) is a common endocrine disorder in women that is associated with an increased prevalence of type 2 diabetes and other cardiovascular risk factors. It remains unclear, however, whether there is an associated increase in cardiovascular events in this condition. Increased prevalence of non‐traditional risk factors, such as abnormalities of inflammation, coagulation, oxidative stress, arterial stiffness and endothelial dysfunction, has recently been reported in PCOS. Collectively, these studies have demonstrated biochemical, functional and structural abnormalities of the cardiovascular system. It seems that many of these cardiovascular abnormalities are related to the presence of insulin resistance and obesity rather than PCOS itself. Cohort studies of long‐term cardiovascular outcome in PCOS and clinical trials of risk factor modification in women with this condition are required. Copyright © 2005 John Wiley & Sons, Ltd.
Vision in diabetes
Authors: Taylor R
Published: November 2005

Arnold Bloom was Consultant Physician at the Whittington Hospital, London. His sound clinical common sense was combined with a scintillating wit. In this lecture I shall describe a series of studies which have been conducted in Newcastle over the last 20 years. Retinal screening has now come of age, and the results in terms of decrease in diabetes blindness are clear. Today's digital retinal images allow trained retinal screeners to explain the result of screening to the patient immediately, and help to set appropriate individual targets for the rest of diabetes care. Copyright © 2005 John Wiley & Sons, Ltd.
Effect of the NCO/OH ratio on the properties of Mesua Ferrea L. seed oil‐modified polyurethane resins
Authors: Dutta Suvangshu , Karak Niranjan
Published: November 2005

A series of polyurethane resins with varying NCO/OH ratios (0.8–2.0) has been synthesized from the monoglyceride of Mesua Ferrea L. seed oil, poly(ethylene glycol) (Mn, 200 g mol−1) and 2,4‐toluene diisocyanate in the presence of dibutyl tin dilaurate as the catalyst. The effects of the NCO/OH ratios of the synthesized resins on the physical properties, such as hydroxy values, acid values, saponification values, iodine values, specific gravities and isocyanate values have been studied. The formation of the polyurethane resins was confirmed by viscosity measurements, and FTIR, UV and 1H NMR spectroscopic studies. Performance characteristics, such as impact resistance, flexibility, gloss, hardness, adhesive strength and chemical resistance, of the cured resins were investigated as a function of the varying NCO/OH ratios, with an influence of these ratios being observed for most of the above properties. Thermogravimetric analysis (TGA) demonstrated that the thermal stabilities of the cured resins increased with an increase in the NCO/OH ratios. The amounts of char residues at 550 °C were also found to be greater for higher NCO/OH ratios of the oil‐modified polyurethane resins. Copyright © 2005 Society of Chemical Industry
Structural characteristics of chemical vapor polymerized polypyrrole/polycaprolactam fiber composites
Authors: Xiao CF , Tao XM , Leung Sarah MY , Kwok Keith WY
Published: November 2005

Structural characteristics of polypyrrole (PPy)‐coated polycaprolactam (PA6) fiber composites prepared by chemical vapor deposition, in the presence of ferric chloride as the oxidizing agent, were investigated. A multi‐layered coating structure was observed by transmission electron microscopy (TEM), where a compact and denser layer existed between the PPy and PA6 fibers with two diffused layers on each side of the denser layer. The compact layer had a thickness of 200–300 nm. The experimental results show that there was no chemical interaction between PPy and PA6 in the PPy‐coated PA6 fibers. However, there was a stronger interaction between PPy and PA6 molecules in the interphase of PPy‐coated PA6 fiber after heat treatment at elevated temperature. The surface morphology of PPy‐coated PA6 fibers changed with the application of different processing treatments, e.g. swelling and heat treatment. Copyright © 2005 Society of Chemical Industry
Synthesis of block copolymers with thermodynamically compatible chain segments: di‐ and triblock copolymers of polystyrene and poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Nagelsdiek René , Keul Helmut , Höcker Hartwig
Published: November 2005

Mono‐ and bifunctional poly(phenylene oxide) (PPO) macroinitiators for atom transfer radical polymerization (ATRP) were prepared by esterification of mono‐ and bishydroxy telechelic PPO with 2‐bromoisobutyryl bromide. The macroinitiators were used for ATRP of styrene to give block copolymers with PPO and polystyrene (PS) segments, namely PPO‐block‐PS and PS‐block‐PPO‐block‐PS. Various ligands were studied in combination with CuBr as ATRP catalysts. Kinetic investigations revealed controlled polymerization processes for certain ligands and temperature ranges. Thermal analysis of the block copolymers by means of DSC revealed only one glass transition temperature as a result of the compatibility of the PS and PPO chain segments and the formation of a single phase; this glass transition temperature can be adjusted over a wide temperature range (ca 100–199 °C), depending on the composition of the block copolymer. Copyright © 2005 Society of Chemical Industry
Proteomics‐based analysis of a counter‐oxidative stress system in Porphyromonas gingivalis
Authors: Okano Soichiro , Shibata Yasuko , Shiroza Teruaki , Abiko Yoshimitsu
Published: November 2005

Porphyromonas gingivalis is a Gram‐negative anaerobic pathogen associated with chronic periodontitis. Although anaerobic, P. gingivalis exhibits a high degree of aerotolerance, which enables it to survive within periodontal pockets. The aim of the present study was to examine the effect of oxidative stress on protein expression in P. gingivalis to obtain a better understanding of the mechanism underlying its aerotolerance. To accomplish this, P. gingivalis cells were grown under conditions of hemin limitation (0.01 μg/mL) to avoid the oxygen protective effect of hemin on oxidative stress. The proteins were then extracted from cultures either left untreated or subjected to oxidative stress and separated by 2‐DE. The resultant protein expression profiles were examined by image scanning, and those found to differ depending on the presence or absence of aeration were subjected to MALDI‐MS and then analyzed using the ORF database of P. gingivalis W83 from The Institute of Genomic Research. Oxidative stress was found to affect the expression of numerous proteins in P. gingivalis cells. In particular, the levels of HtpG, GroEL, DnaK, AhpC, TPR domain protein, and trigger factor were substantially increased.
A study of Streptococcus thermophilus proteome by integrated analytical procedures and differential expression investigations
Authors: Arena Simona , D'Ambrosio Chiara , Renzone Giovanni , Rullo Rosario , Ledda Luigi , Vitale Filomena , Maglione Giuseppe , Varcamonti Mario , Ferrara Lino , Scaloni Andrea
Published: November 2005

Streptococcus thermophilus is a Gram‐positive bacterium belonging to the group of lactic acid bacteria, among which several genera play an essential role in manufacture of food products. Recently, a genomic consortium sequenced and annotated its entire genome, which has been demonstrated to contain 1900 coding sequences. In this study, we have revealed the expression products of almost 200 different genes using a proteomic strategy combining 2‐DE plus MALDI‐TOF PMF and differential 1‐DE plus μLC‐ESI‐IT‐MS/MS. Thus, a number of cellular pathways related to important physiological processes were described at the proteomic level. Almost 50 genes were related to multiple electrophoretic species, whose heterogeneity was mainly due to variability in pI values. A 2‐DE reference map obtained for lactose‐grown cells was compared with those obtained after heat, cold, acid, oxidative and starvation stresses. Protein up/down‐regulation measurements demonstrated that adaptation to different environmental challenges may involve the contribution of unique as well as combined physiological mechanisms. Common regulatory sites in the promoter region of genes whose expression was induced after stress were identified. These results provide a better comprehension of biochemical processes related to stress resistance in S. thermophilus, allowing defining the molecular bases of adaptative responses or markers for the identification of strains with potential industrial applications.
Synthesis of phosphonated copolymers with tailored architecture by reversible addition‐fragmentation chain transfer polymerization (RAFT)
Authors: Rixens Bérengère , Severac Romain , Boutevin Bernard , Lacroix‐Desmazes Patrick
Published: November 2005

The synthesis by reversible addition‐fragmentation chain transfer (RAFT) polymerization of three phosphonated terpolymers with tailored architecture has been studied. A phosphonated methacrylate (MAUPHOS) was copolymerized with vinylidene chloride (VC2) and methyl acrylate (MA) to prepare a gradient terpolymer poly(VC2‐co‐MA‐co‐MAUPHOS). Besides, hydroxyethyl acrylate (HEA) was used as a functional monomer in RAFT polymerization to prepare a statistical poly(VC2‐co‐MA‐co‐HEA) terpolymer and a diblock poly(VC2‐co‐MA)‐b‐poly(HEA) terpolymer. The HEA‐containing polymers were then modified with a phosphonated epoxide to introduce the phosphonated group. The control of the polymerization was proven by kinetic studies (evolution of molecular weight vs. conversion) and by a successful block copolymerization. The architecture of the terpolymers was determined by the reactivity ratios of the monomers: terpolymerization of VC2, MA, and HEA leading to an ideal statistical terpolymer (no composition drift) whereas terpolymerization of VC2, MA, and the phosphonated methacrylate led to a gradient terpolymer. These terpolymers were characterized by size exclusion chromatography, 31P NMR and differential scanning calorimetry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 13–24, 2006
Synthesis and characterization of poly(fluorene)‐based copolymer containing triphenylamine group
Authors: Kim Yun‐Hi , Zhao Qinghua , Kwon Soon‐Ki
Published: November 2005

The copolymers that are composed of poly(fluorene) (PF), poly(p‐phenylene), and Poly(p‐phenylenevinylene) as backbone and a large 4′‐(N,N′‐diphenylamino)diphenyl or 4′‐(N,N′‐diphenylamino)phenyl as pendent group were synthesized by the nickel(0)‐mediated polycoupling. The composition of the obtained copolymers was confirmed by H NMR. All the copolymers possessed a high weight‐average molecular weight and good solubility in common organic solvents. As the content of triphenyl amine pendants increases, the copolymers showed increased thermal stability due to increased glass transition temperature and increased hole injection ability because of decreased onset of the oxidation potential. In the photoluminescence spectra of copolymers, poly (BDAV30‐co‐DHF70) and poly(BDAPV30‐co‐DHF70) showed efficient energy transfer. indium tin oxide/poly(styrene sulfonate)‐doped poly(3,4‐ethylene dioxythiophene)/poly (BDAV30‐co‐DHF70)/LiF/Al device showed maximum brightness of 2267 cd/m2 and efficiency of 0.80 cd/A, with turn‐on voltage at 9.1 V. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 172–182, 2006
Novel synthesis of N‐substituted polyacrylamides: Derivatization of poly(acrylic acid) with amines using a triazine‐based condensing reagent
Authors: Thompson Kimberlee , Michielsen Stephen
Published: November 2005

Poly(acrylic acid) (PAA) was derivatized through the reaction of its pendant carboxylic acid (CO2H) groups with a wide range of amine‐terminated molecules. These molecules contained alkyl, hydroxyl, sulfonic acid, or perfluoroalkyl groups. N‐substitution of PAA was carried out by the simple addition of 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methylmorpholinium chloride (DMTMM), a triazine‐based condensing reagent, to a mixture of PAA and amine‐terminated molecules. From proton nuclear magnetic resonance and infrared spectroscopy, it was confirmed that these functional molecules were introduced into the PAA side chain via amide bonds. By the alteration of the synthetic conditions, functional side‐chain contents of greater than 95% were achieved for aqueous reactions with taurine, ethanol amine, and butyl amine. Side‐chain conversion was limited to ≤80% for reactions with perfluoroalkyl amines in methanol. Thus, DMTMM is an attractive replacement for carbodiimide condensing reagents such as 1,3‐dicyclohexylcarbodiimide and 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 126–136, 2006
Ethylene polymerization by novel Ziegler–Natta‐type catalysts obtained in situ by the oxidative addition of 8‐hydroxyquinoline‐based ligands to bis(1,5‐cyclooctadiene)nickel(0) and methylaluminoxane
Authors: Carlini Carlo , De Luise Valentina , Galletti Anna Maria Raspolli , Sbrana Glauco
Published: November 2005

Novel catalytic systems, prepared in situ by the oxidative addition of 8‐hydroxyquinoline ligands to bis(1,5‐cyclooctadiene)nickel(0) and activated by methylaluminoxane, were studied in ethylene polymerization. When 8‐hydroxyquinoline was employed, only oligomeric products were obtained. On the contrary, 5,7‐dinitro‐8‐hydroxyquinoline gave linear polyethylene (PE), but with a modest activity. For the catalyst based on 5‐nitro‐8‐hydroxyquinoline, the productivity was largely dependent on the content of free trimethylaluminum (TMA) present in the commercial aluminoxane. The progressive optimization of the TMA/oligomeric methylaluminoxane ratio increased the productivity, which reached 700 kg of PE/(mol of Ni × h), by an order of magnitude. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 200–206, 2006
Synthesis of biodegradable copolymers with low‐toxicity zirconium compounds. IV. Copolymerization of glycolide with trimethylene carbonate and 2,2‐dimethyltrimethylene carbonate: Microstructure analysis of copolymer chains by high‐resolution nuclear magnetic resonance spectroscopy
Authors: Dobrzynski Piotr , Kasperczyk Janusz
Published: November 2005

The results of the copolymerization of glycolide with cyclic trimethylene carbonate and 2,2‐dimethyltrimethylene carbonate are described. The copolymerization was conducted in the presence of low‐toxicity zirconium(IV) acetylacetonate as an initiator. With this kind of initiator, the composition of the comonomer units in the copolymer chains was assumed to be obtained with high efficiency. Despite significant differences in the comonomer reactivity, in copolymers containing comparable amounts of glycolidyl and carbonate sequences, highly randomized chain structures were observed. This effect resulted from strong intermolecular transesterification that proceeded during the studied copolymerization and caused glycolidyl microblock randomization. The assignment of the spectral NMR lines to appropriate comonomer sequences of polymeric chains was performed in the region of methylene protons of glycolidyl units in 1H NMR spectra of the copolymers and in the carbonyl region of carbon spectra. The equations were formulated for a detailed characterization of the obtained copolymer chains, the average lengths of the blocks, and the transesterification and randomization coefficients. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 98–114, 2006
Phenylglycine derivatives as coinitiators for the radical photopolymerization of acidic aqueous formulations
Authors: Ullrich G. , Burtscher P. , Salz U. , Moszner N. , Liska R.
Published: November 2005

Aromatic amines are known to give very poor performance as coinitiators for camphorquinone in the photopolymerization of acidic aqueous formulations. Differential scanning photocalorimetry investigations using N‐phenylglycine (NPG) as an alternative coinitiator proved the suitability of this derivative. Furthermore, it was demonstrated that the generally poor photoreactivity had to be assigned to the presence of water and not to the acidity of the formulation. The poor storage stability of NPG‐containing formulations was significantly improved by derivatives containing electron‐withdrawing substituents in the para position of the aromatic moiety, and the photoreactivity was kept at a very high level. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 115–125, 2006
Control of the conjugation length and solubility in electroluminescent polymers
Authors: Stone David A. , Chang Youngkyu , Allcock Harry R.
Published: November 2005

A new type of cyclolinear polymer, poly(phenylene vinylene‐alt‐cyclotriphosphazene), was synthesized through Heck‐type coupling reactions to produce π‐conjugated macromolecules with excellent solubility and precise electronic control of the band‐gap energy. This synthesis method is capable of producing well‐defined alternating polymers. The method is highly adaptable and can be readily used for other chromophore systems. The resulting polymers were also capable of accommodating a wide variety of substituents on the cyclophosphazene rings with minimal effect on the electronic properties. The band gap and electron affinities of the polymer were varied through the manipulation of the π‐conjugated unit located between the insulating phosphazene rings. Each chromophore matched the intended conjugation length consistently throughout the macromolecules. The polymers were good film formers because of the chosen substituents on the phosphazene rings. The absorbance of the polymers indicated minimal spectral shift from the monomer absorbance. This suggested an effective insulation of each chromophore unit from its neighbors by the phosphazene rings. Solution photoluminescence efficiencies were found to be up to 44.1%. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 69–76, 2006
A copper‐based reverse atom‐transfer radical polymerization process for the living radical polymerization of polyacrylonitrile
Authors: Hou Chen , Ji Chunnuan , Wang Chunhua , Qu Rongjun
Published: November 2005

The reverse atom‐transfer radical polymerization (RATRP) technique using CuCl2/2,2′‐bipyridine (bipy) complex as a catalyst was applied to the living radical polymerization of acrylonitrile (AN). A hexasubstituted ethane thermal iniferter, diethyl 2,3‐dicyano‐2,3‐diphenylsuccinate (DCDPS), was firstly used as the initiator in this copper‐based RATRP initiation system. A CuCl2 to bipy ratio of 0.5 not only gives the best control of molecular weight and its distribution, but also provides rather rapid reaction rate. The rate of polymerization increases with increasing the polymerization temperature, and the apparent activation energy was calculated to be 57.4 kJ mol−1. Because the polymers obtained were end‐functionalized by chlorine atoms, they were used as macroinitiators to proceed the chain extension polymerization in the presence of CuCl/bipy catalyst system via a conventional ATRP process. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 226–231, 2006
Low temperature TEMPO‐mediated styrene polymerization in miniemulsion
Authors: Cunningham Michael F. , Ng David C. T. , Milton Sarah G. , Keoshkerian Barkev
Published: November 2005

The 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO)‐mediated stable free radical polymerization of styrene in miniemulsion at 100 °C is demonstrated. Although this temperature is 20–35 °C lower than typical temperatures used for TEMPO‐mediated polymerizations, reasonable reaction rates were achieved by the addition of ascorbic acid or a free radical initiator. More importantly, the living character of the chains was preserved; the degree of polymer “livingness” was comparable to polymerizations conducted at 135 °C. Polydispersities were broader than that observed in well‐controlled systems, ranging from ∼1.4–1.6, and consistent with expectations for systems having a low activation rate. The results are significant for two reasons. They will facilitate TEMPO‐mediated minemulsion polymerizations in nonpressurized (or minimally pressurized) reactors, and they reveal the potential to expand the traditional temperature range of TEMPO and possibly other nitroxides in bulk, solution, and miniemulsion. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 232–242, 2006
Interfacial living radical copolymerization of oil‐ and water‐soluble comonomers to form composite polymer capsules
Authors: Ali Mir Mukkaram , Stöver Harald D. H.
Published: November 2005

The suspension copolymerization of methyl methacrylate with hydroxy‐functional poly(ethylene glycol) monomethacrylate (PEGMA) by atom transfer radical polymerization (ATRP) yielded soluble, controlled‐molecular‐weight amphiphilic copolymers (weight‐average molecular weight/number‐average molecular weight <1.3). Despite extensive partitioning of PEGMA into the water phase, copolymers containing up to 24 mol % PEGMA were formed in the oil phase, from comonomer feeds containing 30 mol % PEGMA. Conversions by suspension polymerization were comparable to those obtained by solution polymerization, at over 70%. Suspension copolymers with high PEGMA contents contained high‐molecular‐weight polymer formed by uncontrolled polymerization, unless poly(vinyl pyrrolidone) was added to displace the growing polymer from the interface. The addition of diethylene glycol dimethacrylate gave capsules at 17 mol % PEGMA with ATRP, whereas conventional free‐radical polymerization required 24 mol % PEGMA to form capsules. The lower PEGMA level required for capsule formation with ATRP was attributed to the lower rates of propagation and crosslinking and to improved incorporation of PEGMA into the final gels. Suspension ATRP with 24 mol % PEGMA in the feed gave two‐layer capsule walls consisting of an inner layer visible by transmission electron microscopy and an outer layer visible by both transmission electron microscopy and environmental scanning electron microscopy, which indicated a compositional gradient across the capsule wall. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 156–171, 2006