bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenesis and prevalence of variant Creutzfeldt–Jakob disease
Authors: Hilton David A
Published: December 2005

In the late 1980s and early 1990s, there was widespread exposure of the UK population to bovine spongiform encephalopathy (BSE)‐contaminated food products, which has led to over 150 deaths from variant Creutzfeldt–Jakob disease (vCJD). Although the pathogenesis in humans is not fully understood, data from animal models and, to a lesser extent, patients with vCJD suggest that oral exposure to BSE is rapidly followed by accumulation of PrPres in gut‐associated lymphoid tissue, then, after haematogenous spread, throughout the lymphoreticular system. Spread to the central nervous system may not occur for several years, but blood from individuals in the pre‐clinical phase appears to be able to transmit disease. The incidence of vCJD has remained low and is in decline, but it is known from iatrogenic CJD and kuru that human prion disease can have incubation periods of up to 40 years. Cases of vCJD are therefore likely to occur for many more years and alternative phenotypes may develop in individuals with different PRNP genotypes to those seen to date. Studies in transgenic mice have shown that sub‐clinical infection is frequent following oral exposure to BSE and a study looking at the accumulation of PrP in anonymized human lymphoid tissue samples found positive cases. There are likely to be a number of asymptomatic ‘carriers’ of disease within the UK and although it is unclear whether these individuals will develop clinical disease, there is a potential for iatrogenic spread to others. These uncertainties highlight the importance of developing a reliable blood test for vCJD and the continued need for surveillance. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Subversion of cellular functions by Listeria monocytogenes
Authors: Pizarro‐Cerdá Javier , Cossart Pascale
Published: December 2005

Listeria monocytogenes is a Gram‐positive bacterium that is able to invade and multiply within eukaryotic cells. Its intracellular life‐cycle includes pathogen‐induced phagocytosis, lysis of the phagocytic vacuole, movement in the cytoplasmic environment, and a cell‐to‐cell spread mechanism. Many L. monocytogenes virulence factors have been studied in detail, certain of which subvert specific eukaryotic cell functions in order to favour infection. During entry, the invasion protein InlA takes advantage of the adhesion molecule E‐cadherin and the adherens junction machinery to adhere to target and invade polarized epithelial cells. Another invasion protein of the internalin family, InlB, subverts the signalling pathway of the hepatocyte growth factor receptor Met to induce endocytosis of the receptor and also to favour internalization of the bacteria in non‐polarized epithelial cells. Once inside the cell, the haemolysin of L. monocytogenes—the listeriolysin O or LLO—is secreted to lyse the phagocytic vacuole, and when the bacteria is freed in the cytoplasm, the activity of the LLO is in part regulated by the infected cell itself, taking advantage of the pH sensitivity of the LLO that leads to its inactivation in the neutral eukaryotic cell cytoplasm. Finally, to induce bacterial movement in the cytoplasm, the L. monocytogenes surface protein ActA mimics the activity of the eukaryotic WASP family of proteins to recruit to the bacteria the actin nucleation machinery required for actin polymerization and for the formation of the actin structures (called ‘actin comet tails’) that propel the parasite in the cytosol and help it to invade neighbouring cells. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
HPV‐associated skin disease
Authors: Akgül Baki , Cooke James C , Storey Alan
Published: December 2005

Human papillomaviruses (HPVs) are DNA tumour viruses that induce hyperproliferative lesions in cutaneous and mucosal epithelia. The relationship between HPV and non‐melanoma skin cancer (NMSC) is important clinically since NMSC is the most common form of malignancy among fair‐skinned populations. It is well established that solar ultraviolet (UV) irradiation is the major risk factor for developing NMSC, but a pathogenic role for HPV in the development of NMSC has also been proposed. Recent molecular studies reveal a likely role for HPV infection in skin carcinogenesis as a co‐factor in association with UV. This review summarizes the literature describing these data, highlights some of the important findings derived from these studies, and speculates on future perspectives. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Viral gene therapy strategies: from basic science to clinical application
Authors: Young Lawrence S , Searle Peter F , Onion David , Mautner Vivien
Published: December 2005

A major impediment to the successful application of gene therapy for the treatment of a range of diseases is not a paucity of therapeutic genes, but the lack of an efficient non‐toxic gene delivery system. Having evolved to deliver their genes to target cells, viruses are currently the most effective means of gene delivery and can be manipulated to express therapeutic genes or to replicate specifically in certain cells. Gene therapy is being developed for a range of diseases including inherited monogenic disorders and cardiovascular disease, but it is in the treatment of cancer that this approach has been most evident, resulting in the recent licensing of a gene therapy for the routine treatment of head and neck cancer in China. A variety of virus vectors have been employed to deliver genes to cells to provide either transient (eg adenovirus, vaccinia virus) or permanent (eg retrovirus, adeno‐associated virus) transgene expression and each approach has its own advantages and disadvantages. Paramount is the safety of these virus vectors and a greater understanding of the virus–host interaction is key to optimizing the use of these vectors for routine clinical use. Recent developments in the modification of the virus coat allow more targeted approaches and herald the advent of systemic delivery of therapeutic viruses. In the context of cancer, the ability of attenuated viruses to replicate specifically in tumour cells has already yielded some impressive results in clinical trials and bodes well for the future of this approach, particularly when combined with more traditional anti‐cancer therapies. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
How the SARS coronavirus causes disease: host or organism?
Authors: Lo Anthony WI , Tang Nelson LS , To Ka‐Fai
Published: December 2005

The previous epidemic of severe acute respiratory syndrome (SARS) has ended. However, many questions concerning how the aetiological agent, the novel SARS coronavirus (CoV), causes illness in humans remain unanswered. The pathology of fatal cases of SARS is dominated by diffuse alveolar damage. Specific histological changes are not detected in other organs. These contrast remarkably with the clinical picture, in which there are apparent manifestations in multiple organs. Both pathogen and host factors are important in the pathogenesis of SARS. The choice of specific receptors and the unique genome of the SARS‐CoV are important elements in understanding the biology of the pathogen. For the host cells, the outcome of SARS‐CoV infection, whether there are cytopathic effects or not, depends on the cell types that are infected. At the whole‐body level, immune‐mediated damage, due to activation of cytokines and/or chemokines and, perhaps, autoimmunity, may play key roles in the clinical and pathological features of SARS. Continued research is still required to determine the pathogenetic mechanisms involved and to combat this new emerging human infectious disease. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Innate defences against methicillin‐resistant Staphylococcus aureus (MRSA) infection
Authors: Komatsuzawa Hitoshi , Ouhara Kazuhisa , Yamada Sakuo , Fujiwara Tamaki , Sayama Koji , Hashimoto Koji , Sugai Motoyuki
Published: December 2005

The innate immune system is the primary defence against bacterial infection. Among the factors involved in innate defence, anti‐microbial peptides produced by humans have recently attracted attention due to their relevance to some diseases and also to the development of new chemotherapeutic agents. Staphylococcus aureus is one of the major human pathogens, causing a variety of infections from suppurative disease to food poisoning. Methicillin‐resistant S. aureus (MRSA) is a clinical problem and with the recent emergence of a vancomycin‐resistant strain, this will pose serious problems in the near future. In investigating the molecular biology of S. aureus infections to develop new chemotherapeutic agents against MRSA infections, knowledge of the interaction of innate anti‐microbial peptides with S. aureus is important. In vitro and in vivo experiments demonstrate that exposure of S. aureus to host cells can induce the anti‐microbial peptides β‐defensin‐2 (hBD2), hBD3, and LL37/CAP18. The induction level of these peptides differs among strains, as does the susceptibility of the strains, with MRSA strains exhibiting lower susceptibility. In summary, the susceptibility of S. aureus strains, including MRSA strains, to components of the innate immune system varies, with the MRSA strains showing more resistance to both innate immune factors and chemotherapeutic agents. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The pathogenesis of syphilis: the Great Mimicker, revisited
Authors: Peeling Rosanna W , Hook Edward W
Published: December 2005

Syphilis is a chronic sexually transmitted infection caused by Treponema pallidum subspecies pallidum. Its protean clinical presentations earned it the name of the ‘Great Mimicker’. Understanding of disease pathogenesis and how host–pathogen interactions influence the course of disease have been compromised by the facts that the organism cannot be grown in vitro and, as an exclusively human pathogen, inferences made from animal models are of limited applicability. Many questions remain about how T. pallidum biology contributes to distinctive features of syphilis, such as its ability to persist in the presence of a brisk host response or its propensity for neuro‐invasion and congenital transmission. In 1998, the genome of T. pallidum was sequenced. The organism has a relatively small genome, suggesting that it utilizes host biosynthesis to fulfil some of its metabolic needs. While biological functions are suggested for only about 55% of T. pallidum's 1041 open reading frames, even these relatively early studies offer important insights into syphilis pathogenesis. A family of repeat genes, the Tp genes, encode proteins homologous to the major sheath proteins of T. denticola. Antibodies to the TprK variable regions are protective in a rabbit model. With successive passage, increasing diversity is observed in the TprK V region genes. Antigenic variation through gene conversion has been hypothesized to be one mechanism of escaping immune surveillance, allowing for prolonged infection and persistence in the presence of a robust host response. Human and animal studies suggest that a Th1 response is elicited in primary syphilis. Progression to the secondary stage is accompanied by a shift to a Th2 response, allowing for incomplete clearance of the pathogen. In pregnancy, intense inflammatory responses and prostaglandins induced by fetal infection may be responsible for fetal death or pre‐term delivery and severe growth retardation or other manifestations of congenital syphilis. Understanding of the molecular targets of these immune responses may facilitate the development of vaccines for syphilis. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The pleiotropic effects of Kaposi's sarcoma herpesvirus
Authors: Schulz Thomas F
Published: December 2005

Kaposi's sarcoma herpesvirus (KSHV), or human herpesvirus 8 (HHV8), is an essential factor in the pathogenesis of Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). Case reports suggest an occasional involvement in bone marrow hypoplasia and haemophagocytic syndrome, but other disease associations are unconfirmed or controversial. KSHV‐associated disease is of particular importance in immunosuppressed individuals, in particular in patients with HIV infection and transplant recipients. KSHV establishes a latent infection in the majority of infected cells in KS, MCD, and PEL, but lytic replication occurs in a small fraction of infected cells. Viral proteins expressed during both the latent and the lytic phase of the viral life cycle contribute to the pathogenesis of KSHV‐associated diseases. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Viruses and lymphoma/leukaemia
Authors: Jarrett Ruth F
Published: December 2005

Viruses of the retrovirus and herpesvirus families are aetiological agents of human leukaemias and lymphomas. The human T‐cell leukaemia virus type 1 causes adult T‐cell leukaemia and the Epstein–Barr virus is associated with Burkitt's lymphoma, lymphomas in immunosuppressed people, and Hodgkin lymphoma. The discovery of human herpesvirus type 8 has led to the identification of a rare and unusual group of virus‐associated lymphoproliferative diseases. Individuals infected with the human immunodeficiency virus are at greatly increased risk of developing lymphoma but here the mechanism of lymphomagenesis is indirect. Recent data suggest that hepatitis C virus infection is also associated with an increased incidence of lymphoma, whereas data relating to SV40 remain controversial. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
New insights into the function of granulomas in human tuberculosis
Authors: Ulrichs Timo , Kaufmann Stefan HE
Published: December 2005

The human tuberculous granuloma provides the morphological framework for local immune processes central to the outcome of tuberculosis. This review article describes investigations on human lung granulomas aimed at better understanding the regional host response and counter‐measures to Mycobacterium tuberculosis. These findings lead to a revised view of the regional immune response in human tuberculosis. Novel insights into this dynamic cross‐talk form the basis of novel intervention strategies. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The p38 transduction pathway in prostatic neoplasia
Authors: Ricote M , García‐Tuñón I , Bethencourt F , Fraile B , Onsurbe P , Paniagua R , Royuela M
Published: December 2005

It has been proposed that, among other cellular responses, TNF‐α induces not only cell death, but also cell proliferation by activation of p38. It has also been reported that IL‐1‐α favours cell proliferation by p38 activation. The aim of the present study was to evaluate upstream (α‐PAK, MEK‐6) and downstream (Elk‐1 and ATF‐2) components of the p38 transduction pathway in normal prostate, benign prostatic hyperplasia (BPH), and prostate carcinoma (PC). Immunohistochemical and western blot analyses were performed in 20 samples of normal prostate, 47 samples of BPH, and 27 samples of PC. In all normal prostates, immunoreactivity for p‐Elk‐1 and p‐ATF‐2 was observed in epithelial cell nuclei, but no expression of α‐PAK or MEK‐6. In BPH, there was expression of α‐PAK (cytoplasm) and MEK‐6 (cytoplasm), while the proportions of lesions that were immunoreactive for p‐Elk‐1 (nucleus and cytoplasm) and p‐ATF‐2 (nucleus) decreased. In PC, the percentages of cells that were immunoreactive for α‐PAK (cytoplasm) or MEK‐6 (cytoplasm) rose slightly in comparison with BPH, while the percentages of cells that were immunoreactive for p‐Elk‐1 (nucleus and cytoplasm) or p‐ATF‐2 (nucleus and cytoplasm) were much higher than in BPH. It is concluded that overexpression of α‐PAK, MEK‐6, p38, p‐Elk‐1, and p‐ATF‐2 in BPH, and more intensely in PC, enhances cell proliferation. In BPH, such proliferation is triggered by IL‐1 and in part counteracted by the TNF‐α/AP‐1 pathway, which promotes apoptosis. In PC, proliferation is triggered by IL‐1 and TNF‐α (the TNF‐α/AP‐1 pathway is diverted towards p38 activation). Since in a study of the same patients immunoexpression of IL‐1α and IL‐1RI was previously observed to be increased in PC, inhibition of p38 is a possible target for PC treatment, as this inhibition would both decrease IL‐1‐induced cell proliferation and increase TNF‐α‐induced cell death. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Infection and disease: cause and cure
Authors: Herrington C Simon , Douek Daniel C
Published: December 2005

Much can be learnt about the mechanisms by which micro‐organisms cause disease from the ways that they interact with cells and tissues. This issue of The Journal of Pathology contains articles that address the roles that cell and tissue biology and pathology are playing in the elucidation of these mechanisms. A review of variant Creutzfeldt–Jakob disease is followed by a discussion of severe acute respiratory syndrome (SARS). Two articles on human papillomavirus (HPV) infection address the association between viral infection and neoplasia, as do reviews on viruses and lymphoma/leukaemia, and Kaposi's sarcoma‐associated herpesvirus (human herpesvirus 8, HHV8). The section on viral disease concludes with an article on morbilliviruses. The intracellular effects of bacteria are addressed in a review of Listeria infection and a further review outlines recent advances in our knowledge of syphilis. Reviews on Helicobacter and gastric neoplasia, innate defences against methicillin‐resistant Staphylococcus aureus (MRSA) infection, and the function of granulomas in tuberculosis also address aspects of tissue responses to bacterial infection. Following a review of the function of immunoglobulin A in defence against infection, a group of articles considers vaccination and gene therapy approaches, the latter involving consideration of both viral and bacterial strategies. The reviews assembled here bridge several gaps: between microbiology and cellular pathology; between host and infecting organism; and between disease and therapy. It is clear that cell and tissue pathology approaches are of value in all of these spheres, providing cell and tissue relevance to microbiological and immunological observations. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Growth hormone deficiency after chemotherapy for acute lymphoblastic leukemia in children who have not received cranial radiation
Authors: Haddy Theresa B. , Mosher Revonda B. , Nunez Susan B. , Reaman Gregory H.
Published: December 2005

Chemotherapy‐related growth failure is a significant problem in children with acute lymphoblastic leukemia (ALL) and other childhood cancers. Growth impairment after cranial radiation (CR) can result in diminished adult height, but growth failure following chemotherapy without CR is usually followed by catch‐up growth and normal adult height.1 A retrospective review of 347 ALL survivors registered in our Long Term Follow Up (LTFU) Clinic, since 1997 revealed that 109 had received CR; 3, total body irradiation (TBI); and 235, neither CR nor TBI. For patients whose growth velocity slowed, growth hormone (GH) levels and pediatric endocrinology referrals were obtained. Among the 112 ALL survivors who had received some form of CR, 5 had significant growth failure with growth hormone deficiency (GHD). Among the 235 ALL survivors treated with chemotherapy without CR, 2 were diagnosed with growth failure and GHD. We report the two survivors of childhood ALL treated with chemotherapy without CR who required GH replacement due to absence of catch‐up growth. A 15‐year‐old boy and a 12‐year‐old girl, off therapy for 9 and 6 years, respectively, were evaluated for decreased growth velocity and failure of catch‐up growth. Peak GH responses to stimulation using arginine and clonidine were 3.4 and 3.0 ng/ml, respectively (normal >10 ng/ml). Other causes of growth failure were ruled out, and GH replacement therapy was instituted. Their chemotherapy had included methotrexate, 6 mercaptopurine, vincristine, adriamycin, cyclophosphamide, L‐asparaginase, dexamethasone, cytarabine, 6 thioguanine, and intrathecal methotrexate. The growth of all children treated with intensive chemotherapy, regardless of whether CR was administered, should be closely monitored with measurement of standing height at 6 months intervals until growth is complete. Pediatr Blood Cancer 2006;46:258–261. © 2005 Wiley‐Liss, Inc.
Models of care for survivors of childhood cancer
Authors: Friedman Debra L. , Freyer David R. , Levitt Gill A.
Published: December 2005

With improvements in therapy for childhood cancer, the expectation that most childhood cancer patients will survive and enter adulthood is a reality. There is clear evidence that survivors are at risk for adverse health‐related long‐term sequelae associated with their cancer and its treatment, requiring appropriate health care resources. What is less clear is how this health care should optimally be delivered. We review the functional and operational needs for long‐term follow‐up for childhood cancer survivors and present alternatives for models of care. Programs for childhood cancer survivors should provide mechanisms for monitoring and management of late effects, as well as support and advocacy for addressing psychosocial issues, health education, and assistance with financial concerns. Access to research is an important component as clinical care and research are integrally related. A multidisciplinary model that provides continuity of care throughout the disease course is optimal, providing transitions from acute anti‐neoplastic therapy to follow‐up and primary care, as well as from pediatric care to adult‐oriented care. There is no single best model of care for all childhood cancer survivors. In evaluating different models, considerations include available resources as well as the particular cancer population being served. Not all survivors require the same level of services and the service level requirement for individual patients may change with time. As outcome research progresses for childhood cancer survivors, methodological issues of optimal health care delivery for this population deserve to be the subject of such research. Pediatr Blood Cancer 2006;46:159–168. © 2005 Wiley‐Liss, Inc.
A case series of pediatric primary central nervous system lymphoma: Favorable outcome without cranial irradiation
Authors: Abla Oussama , Sandlund John T. , Sung Lillian , Brock Penelope , Corbett Rob , Kirov Ivan , Griffin Timothy C. , Blaser Susan , Weitzman Sheila
Published: December 2005

Purpose

To describe the outcome of childhood primary central nervous system lymphoma (PCNSL) treated with chemotherapy alone or with chemotherapy plus cranial radiotherapy (CRT).

Methods

Retrospective chart review of children with PCNSL at six tertiary care pediatric centers.

Results

Eight immunocompetent and four immunocompromised children were included. Ten children received chemotherapy alone without CRT, with most receiving high‐dose methotrexate and high‐dose cytarabine. Five year event‐free survival (EFS) in this group was 70.0 ± 14.5%. Two children received chemotherapy plus CRT; one relapsed and died while the other is alive in remission. Three children died, including two from relapsed disease. The other child with human immunodeficiency virus infection died of an opportunistic infection while in remission following chemotherapy alone.

Conclusions

Most children with PCNSL can achieve long‐term remissions with chemotherapy alone without CRT. Multi‐center prospective studies are needed to confirm or refute these results in a larger number of patients. © 2005 Wiley‐Liss, Inc.
Preparation of narrow‐dispersion or monodisperse polymer microspheres with active hydroxyl group by distillation–precipitation polymerization
Authors: Bai Feng , Li Rui , Yang Xinlin , Li Shuning , Huang Wenqiang
Published: December 2005

Narrow‐dispersion or monodisperse polymer microspheres with active hydroxyl groups were prepared by distillation–precipitation polymerization in the absence of any stabilizer. The monomer hydroxyethyl methacrylate (HEMA) was copolymerized with either commercial divinylbenzene (DVB) (containing 80 % of DVB isomers) or ethyleneglycol dimethacrylate (EGDMA) as crosslinker by distillation–precipitation polymerization technique with 2,2′‐azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile. The effects of the crosslinker and the crosslinking degree on the morphology and the loading of the active hydroxyl group of the resultant microspheres were investigated. The agitation caused by distilling off a portion of the polymerization solvent during the polymerization avoided coagulation and resulted in the narrow‐dispersion or monodisperse polymer microspheres for the distillation precipitation technique. Copyright © 2005 Society of Chemical Industry
Alternating polyester/fluoroalkene copolymers: Combining high hydrophobicity with degradability
Authors: Borkar Sachin , Sen Ayusman , Shallenberger Jeffrey R.
Published: December 2005

2‐Methylene‐1,3‐dioxepane (MDO) was copolymerized with fluoroalkenes (RfCHCH2) using azobis(isobutyronitrile) AIBN as an initiator. NMR spectroscopy confirmed that the obtained polymers are effectively alternating copolymers of caprolactone and fluoroalkene. Angle resolved XPS of copolymer films revealed that the outer layers have higher CFx:COO ratio relative to the subsurface, indicating that the perfluoroalkyl tails segregate to the air‐side, thereby presenting a hydrophobic surface with water contact angle as high as 130°. Blends of this material with polycaprolactone and polycarbonate polymers also form hydrophobic films. In the presence of trifluoroacetic acid, the copolymer undergoes complete degradation through hydrolysis. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1225–1232, 2006
New antibacterial cationic surfactants prepared by atom transfer radical polymerization
Authors: Lenoir Sandrine , Pagnoulle Christophe , Detrembleur Christophe , Galleni Moreno , Jérôme Robert
Published: December 2005

Efficient antibacterial surfactants have been prepared by the quaternization of the amino groups of poly(ethylene‐co‐butylene)‐b‐poly[2‐(dimethylamino)ethylmethacrylate] (PEB‐b‐PDMAEMA) diblock copolymers by octyl bromide. The diblock copolymers have been synthesized by ATRP of 2‐(dimethylamino)ethylmethacrylate (DMAEMA) initiated by an activated bromide‐end‐capped poly(ethylene‐co‐butylene). In the presence of CuBr, 1,4,7,10,10‐hexamethyl‐triethylenetetramine (HMTETA), and toluene at 50 °C, the initiation is slow in comparison with propagation. This situation has been improved by the substitution of CuCl for CuBr, all the other conditions being the same. Finally, the addition of an excess of CuCl2 (deactivator) to the CuCl/HMTETA catalyst is very beneficial in making the agreement between the theoretical and experimental number‐average molecular weights excellent. The antibacterial activity of PEB‐b‐PDMAEMA quaternized by octyl bromide has been assessed against bacteria and is comparable to the activity of a commonly used disinfectant, that is, benzalkonium chloride. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1214‐1224, 2006
Measurement and prediction of solubilities and diffusion coefficients of carbon dioxide in starch–water mixtures at elevated pressures
Authors: Chen Kwan‐Han J. , Rizvi Syed S. H.
Published: December 2005

The solubility and diffusion coefficient of carbon dioxide in intermediate‐moisture starch–water mixtures were determined both experimentally and theoretically at elevated pressures up to 16 MPa at 50 °C. A high‐pressure decay sorption system was assembled to measure the equilibrium CO2 mass uptake by the starch–water system. The experimentally measured solubilities accounted for the estimated swollen volume by Sanchez–Lacombe equation of state (S‐L EOS) were found to increase almost linearly with pressure, yielding 4.0 g CO2/g starch–water system at 16 MPa. Moreover, CO2 solubilities above 5 MPa displayed a solubility increase, which was not contributed by the water fraction in the starch–water mixture. The solubilities, however, showed no dependence on the degree of gelatinization (DG) of starch. The diffusion coefficient of CO2 was found to increase with concentration of dissolved CO2, which is pressure‐dependent, and decrease with increasing DG in the range of 50–100%. A free‐volume‐based diffusion model proposed by Areerat was employed to predict the CO2 diffusivity in terms of pressure, temperature, and the concentration of dissolved CO2. S‐L EOS was once more used to determine the specific free volume of the mixture system. The predicted diffusion coefficients showed to correlate well with the measured values for all starch–water mixtures. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 607–621, 2006
Synthesis of hydroxyl‐terminated poly(ether ether ketone) with pendenttert‐butyl groups and its use as a toughener for epoxy resins
Authors: Francis Bejoy , Thomas Sabu , Asari G. Viswanathan , Ramaswamy Rajagopal , Jose Seno , Rao V. Lakshmana
Published: December 2005

Hydroxyl‐terminated poly(ether ether ketone) with pendenttert‐butyl groups (PEEKTOH) was synthesized by the nucleophilic substitution reaction of 4,4′‐difluorobenzophenone withtert‐butyl hydroquinone with potassium carbonate as a catalyst andN‐methyl‐2‐pyrrolidone as a solvent. Diglycidyl ether of bisphenol A epoxy resin was toughened with PEEKTOHs having different molecular weights. The melt‐mixed binary blends were homogeneous and showed a single composition‐dependent glass‐transition temperature (Tg). Kelley–Bueche and Gordon–Taylor equations gave good correlation with the experimentalTg. Scanning electron microscopy studies of the cured blends revealed a two‐phase morphology. A sea‐island morphology in which the thermoplastic was dispersed in a continuous matrix of epoxy resin was observed. Phase separation occurred by a nucleation and growth mechanism. The dynamic mechanical spectrum of the blends gave two peaks corresponding to epoxy‐rich and thermoplastic‐rich phases. TheTgof the epoxy‐rich phase was lower than that of the unmodified epoxy resin, indicating the presence of dissolved PEEKTOH in the epoxy matrix. There was an increase in the tensile strength with the addition of PEEKTOH. The fracture toughness increased by 135% with the addition of high‐molecular‐weight PEEKTOH. The improvement in the fracture toughness was dependent on the molecular weight and concentration of the oligomers present in the blend. Fracture mechanisms such as crack path deflection, ductile tearing of the thermoplastic, and local plastic deformation of the matrix occurred in the blends. The thermal stability of the blends was not affected by blending with PEEKTOH. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 541–556, 2006
Grain shapes and growth kinetics during self‐assembly of block copolymers
Authors: Chastek Thomas Q. , Lodge Timothy P.
Published: December 2005

With block copolymer equilibrium phase behavior becoming increasingly better understood, a more detailed description of ordering kinetics is feasible. This article highlights recent experimental observations that provide new insight into ordering kinetics and grain structures when a block copolymer liquid is first cooled below the order–disorder transition. Measurements have been made on several concentrated poly(styrene‐b‐isoprene) solutions, with concentrations and temperatures adjusted to access the cylinder, lamellar, and gyroid phases. A diverse set of grain types were observed using polarized optical microscopy (POM). Cylinder grains were either oblate ellipsoids or spherulites, whereas the lamellar phase formed prolate ellipsoidal grains, twinned ellipsoidal grains, twofold twinned grains, and spherulites. The orientation of the cylinders and lamellae within the grains were unambiguously identified. The shapes of the ellipsoidal and twinned grains were dictated by the relative interfacial tensions of the available growth surfaces with respect to the disordered state. Grain growth front velocities were also quantified before grain impingement, and consistent values were obtained among different grains for a given sample and quench temperature. The experimental growth velocities were compared to an expression derived by Goveas and Milner. There was good agreement in terms of the temperature dependence, and the absolute magnitude was predicted with some success. The rates of nucleation and overall conversion to the ordered phase were also determined. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 481–491, 2006
Crystallization behavior of poly(ε‐caprolactone)/multiwalled carbon nanotube composites
Authors: Wu Tzong‐Ming , Chen Erh‐Chiang
Published: December 2005

Differential scanning calorimetry (DSC), polarized optical microscopy, and X‐ray diffraction methods were used to investigate the isothermal crystallization behavior and crystalline structure of poly(ϵ‐caprolactone) (PCL)/multiwalled carbon nanotube (MWNT) composites. PCL/MWNT composites were prepared via the mixing of a PCL polymer solution with carboxylic groups containing multiwalled carbon nanotubes (c‐MWNTs). Both Raman and Fourier transform infrared spectra indicated that carboxylic acid groups formed at both ends and on the sidewalls of the MWNTs. A transmission electron microscopy micrograph showed that c‐MWNTs were well separated and uniformly distributed in the PCL matrix. DSC isothermal results revealed that introducing c‐MWNTs into the PCL structure caused strongly heterogeneous nucleation induced by a change in the crystal growth process. The activation energy of PCL drastically decreased with the presence of 0.25 wt % c‐MWNT in PCL/c‐MWNT composites and then increased with increasing MWNT content. The result indicated that the addition of c‐MWNT to PCL induced heterogeneous nucleation (lower total activation energy) at a lower c‐MWNT content and then reduced the transportation ability of polymer chains during crystallization processes at a higher MWNT content (higher total activation energy). A correlation between the crystallization kinetics, melting behavior, and crystalline structure of PCL/c‐MWNT composites was also discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 598–606, 2006
Residual stresses and birefringence in injection molding of amorphous polymers: Simulation and comparison with experiment
Authors: Isayev A. I. , Shyu G. D. , Li C. T.
Published: December 2005

A physical modeling and a two‐dimensional numerical simulation of the injection‐molding of a disk cavity by using a hybrid finite element method (FEM) and finite difference method (FDM) are presented. Three stages of the injection‐molding cycle––filling, packing, and cooling––are included. The total residual stresses are taken to be a sum of the flow stresses calculated using a compressible nonlinear viscoelastic constitutive equation and the thermal stresses calculated using a linear viscoelastic constitutive equation. The total residual birefringence is taken to be the sum of the flow birefringence related to the flow stresses through the stress–optical rule, and the thermal birefringence related to the thermal stresses through the photoviscoelastic constitutive equation. The Tait equation is used to describe the P‐V‐T relationship. The simulation shows that without packing the birefringence in the surface layer of moldings, with its maximum near the surface, is caused by the frozen‐in flow birefringence (flow stresses) and in the core region by the frozen‐in thermal birefringence (thermal stresses). With packing, a second birefringence maximum appears between the center and the position of the first maximum due to flow in the packing stage. The predicted birefringence profiles and extinction angle profiles are found to be in fair agreement with corresponding measurements in literature for disk moldings. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 622–639, 2006
Unusual phase behavior in mixtures of poly(ethylene oxide) and ethyl alcohol
Authors: Ho Derek L. , Hammouda Boualem , Kline Steven R. , Chen Wei‐Ren
Published: December 2005

Poly(ethylene oxide) (PEO), soluble in both aqueous and organic solvents, is one of the most intriguing polymers. PEO solution properties have been extensively studied for decades; however, many of the studies have focused on specific properties, such as clustering, of PEO in aqueous solutions, and the behavior of PEO in organic solvents has not been adequately explored. The results presented here demonstrate that PEO crystallizes into a lamellar structure in ethyl alcohol after the mixture is quenched to room temperature from a temperature above the crystal melting point. Above the melting temperature, PEO completely dissolves in ethyl alcohol, and the mixture exhibits regular polymer solution thermodynamic behavior with an upper critical solution temperature (UCST) phase diagram. Remarkably, the UCST phase boundary is significantly below the melting temperature, and this indicates that the system undergoes a crystallization process before the phase separation can occur upon cooling and, therefore, possesses an unusual phase transition. The phase transition from the crystalline state to the miscible solution state is reversible upon heating or cooling and can be induced by the addition of a small amount of water. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 557–564, 2006
The role of a ‘retirement transition’ in the repopulation of rural areas
Authors: Stockdale Aileen
Published: December 2005

Two of the most important demographic trends to emerge in recent decades have been the growth of a highly mobile ageing population and a deconcentration of persons from urban to rural areas. This paper investigates Bures' (1997) retirement transition hypothesis for the mobility patterns of pre‐retirement age groups in relation to the repopulation of rural areas of England and Scotland. It incorporates household survey data relating to the migration patterns and decisions of those aged between 50 and 64 years. Evidence is obtained to support Bures' hypothesis. It is suggested that an economic transition accompanies any retirement transition. In addition, differences in the nature of the retirement transition are observed between the repopulation of rural England and Scotland. These trends have important policy implications for the future of rural areas. Copyright © 2006 John Wiley & Sons, Ltd.
Place, community education, gender and child mortality in North‐east India
Authors: Ladusingh Laishram , Singh Chungkham Holendro
Published: December 2005

This article examines the relevance of socio‐cultural and environmental factors in explaining child mortality in Northeast India, considered to be the most inaccessible region in the country. Using data from the Indian National Family Health Survey, we provide evidence that lack of hygiene in the household and poor women's engagement in physically demanding agriculture based work contributes to higher risk of child mortality. Unlike in other parts of India, female children have an edge over boys in childhood survival and living with paternal grandmother tends to lower the risk of child death in the first five years of life. Community education is found as the dominant factor outside the household to have a significant effect on child mortality. Copyright © 2006 John Wiley & Sons, Ltd.
Pt/Ga/C and Pt/C composite nanowires fabricated by focused ion and electron beam induced deposition
Authors: Li P. G. , Jin A. Z. , Tang W. H.
Published: December 2005

Pt/Ga/C and Pt/C composite nanowires have been fabricated using ion beam induced deposition (IBID) and electron beam induced deposition (EBID), respectively, with a dual beam focused ion beam system. The Pt/Ga/C composite nanowires usually exhibit a semiconducting character and their resistances increase greatly as the temperature decreases. However, the Pt/C composite nanowires show metallic behaviour above 2 K. The results suggest that EBID is more suitable than IBID for fabricating measuring electrodes for nanomaterials and devices in a single‐step process. It has also been found that the resistance of the Pt/C nanowires decreases abruptly around 20 K, which could arise from a possible new phase formed between Pt and C. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic softening and giant magneto‐impedance effect of Co68Fe4Ni1Si15B12
Authors: Hoque S. Manjura , Hakim M. A. , Khan F. A.
Published: December 2005

Magnetic softening and its correlation with the giant magneto‐impedance effect have been investigated for Co68Fe4Ni1Si15B12 subjected to different annealing temperatures. In the as‐cast condition the Curie temperature is 230 °C and the saturation magnetization is 72.3 emu/g. A very high value of initial permeability of around 59 × 103 and a low value of relative loss factor of the order of 10–6 have been obtained for samples annealed at 420 °C for 1 h. The sensitivity of the field dependence of the giant magneto‐impedance ratio (GMIR) for this annealing temperature is higher than that for as‐cast and other annealed samples. From X‐ray diffraction and differential scanning calorimetry results it has been found that for samples annealed at 420 °C for 1 h the ribbon is in a fully amorphous state. The extraordinary soft magnetic properties at this annealing temperature are mainly due to the structural relaxation, which determines the profile of the field dependence of the GMIR. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical characterisation of thick InN epilayers grown with a single or two step growth process on GaN(0001)
Authors: Delimitis A. , Gladkov P. , Komninou Ph. , Kehagias Th. , Arvanitidis J. , Ves S. , Katsikini M. , Dimakis E. , Georgakilas A.
Published: December 2005

High resolution transmission electron microscopy (HRTEM), Raman spectroscopy and temperature dependent photoluminescence (PL) are employed to compare the structural and optical properties of compact InN films grown by molecular beam epitaxy (MBE) on GaN/Al2O3(0001) with a single‐step (S) or a two‐step (T) growth process. The S‐type film was grown at 300 °C, whilst the T‐type film was nucleated at the same temperature and overgrown at 410 °C. The T‐type film exhibits better structural and optical properties as indicated by a sharper InN/GaN interface, the lower threading dislocations density, sharper Raman peaks and higher intensity PL peaks. Quantitative comparison of the red‐shifted Raman E 22 peak and the lattice constants of S and T samples suggests that the InN epilayers are under different values of stress due to thermal reasons and point defects present in them. The PL emission peak difference of 32 meV between S and T provides further evidence of the unequal residual strain present in InN. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparative study on MOVPE InN films grown on 3c‐SiC/Si(111) and sapphire
Authors: Kobayashi T. , Cho M. S. , Sawazaki N. , Hashimoto A. , Yamamoto A. , Ito Y.
Published: December 2005

This paper reports the MOVPE growth of InN on a 3c‐SiC/Si template formed by C+‐ion implantation into Si(111). Properties of grown films on the template are compared with those grown on sapphire in the same run. By employing the nitridation process of the template at 900 °C for 30 min just before the GaN buffer growth, the buffer layer becomes to show uniform nucleation. This is due to the improved wettability of GaN layer on the template by the formation of Si–N bonds on the Si‐polar SiC layer. The surface mophology of InN film grown on the nitrided template is similar to that for a film grown on a sapphire. The film on the nitrided template shows strong photoluminescence with a peak energy of 0.70 eV at room temperature. The carrier concentration and Hall mobility are 7.6 × 1018 cm–3 and 630 cm2/Vs, respectively. These data are comparable to those for InN grown on the sapphire (0.71 eV, 6.5 × 1018 cm–3 and 870 cm2/Vs). Thus, the nitridation process of the 3c‐SiC/Si template is found to be effective to obtain high‐quality InN film. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time windows of spin squeezed states in a stripe phase
Authors: Peng Feng , Xingkun Man
Published: December 2005

The time evolution of the spin fluctuation in a stripe phase of a superconductor is studied. In a laser field with proper field strength and frequency, the amplitude of the fluctuation may be very small in some time regions (time windows), and even smaller than the level of the vacuum fluctuation. The corresponding states are called the spin squeezed states. The conditions for achieving the spin squeezed states are given, and a possible detecting scheme is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antiferroelastic structural transitions in PrAlO3 by means of neutron diffraction
Authors: Watanabe S. , Hidaka M. , Yoshizawa H. , Wanklyn B. M.
Published: December 2005

Structural phase transitions of the perovskite‐type PrAlO3 have been studied by using neutron diffraction. The results show that, on cooling, the structures are successively transformed from R$ \bar 3 $c (Phase II) to Imma (Phase III), Imma (Phase IV), I4/mcm (Phase V) by the 215‐K, 153‐K, and 122‐K transitions. The tilting schemes in Phase III, IV and V are mainly characterized by (ψa = ψc, ψb = 0), (ψa ≠ ψc, ψb = 0), and (ψc, ψa = ψb = 0), respectively, where ψa, ψb and ψc are rotational angles around a‐, b‐, and c‐primitive axes of the AlO6 octahedron. The refreezes of the condensed Rand R optical soft modes occurring at about 215 K and 122 K are interpreted by correlation with the cooperative Jahn–Teller distortion (JTD) of the Pr3+–4f orbitals in the PrO12 polyhedra. The phase IV is characterized as an intermediate state, in which the ψa tilts are continuously reduced by the JTD and disappear just above the 122‐K transition. The easy mobility of the domain walls suggests the PrAlO3 crystal to be of antiferroelastic nature, an unusual property that results from the cooperative displacements of O ions induced by the correlation between the antiphase tilts along primitive axes of the AlO6 octahedra and the JTD around Pr+3 ions in PrO12 polyhedra. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Creation of CsAu nanoclusters by UV‐light irradiation on CsBr:Au– crystals
Authors: Kawai Taketoshi , Yamano Asuka
Published: December 2005

We have investigated the optical absorption spectra of the CsBr:Au– crystals irradiated with an ultraviolet (UV) light. Before the UV‐light irradiation, the absorption bands associated with the isolated Au– ion (monomer) are observed in the energy region of UV. After a slight UV‐light irradiation, the absorption intensities of the monomer bands decrease and the absorption bands due to paired Au– ions appear around the monomer bands. Furthermore, UV‐light irradiation on the CsBr:Au– crystals brings about the appearance of several new absorption bands in the visible region. From the analogy with the aggregation of the F centers in alkali halide crystals, the new absorption bands are attributed to the aggregate centers of the Au– ions. They can also be regarded as the CsAu nanocluster constructed from the Cs+ cations and the Au– anions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)