bluuebunny/crossref_metadata_2025 huggingface dataset:
Tempo‐spatial covariance structure of lentil yield and water use efficiency from supplemental irrigation trials
Authors: Singh M. , Oweis T. , Pala M. , Sarker A.
Published: March 2006

In agricultural research conducted in dry areas, crop‐yield water use efficiency (WUE) is a measure used to evaluate the impacts of various agronomic factors on crop productivity. Agronomic management factors include supplemental irrigation (SI) and crop‐rotation systems, which are used to increase the sustainability of crop production systems. A study of lentil (Lens culinarisMedikus) was conducted in split‐plot experiments in randomized complete blocks, where planning date (PD) were assigned to main‐plots and SI to sub‐plots. Lentil was grown in rotation with durum wheat (i.e., lentil was grown 1 year and durum wheat the next, on the same plot of land) over a period of 4 years (1996/1997–1999/2000) at the research station of the International Center for Agricultural Research in the Dry Areas (ICARDA), at Tel Hadya, Syria. Spatial variability in the field trials and correlations between the plot errors arising over time were studied to examine their effects on the significance and precision of the estimates of the effects of PD and SI on yields (of both seed and total biomass) and WUE. The analyses revealed the presence of significant linear soil‐fertility trends within the fields and strongly auto‐correlated plot errors. When these trends were accounted for in the analysis of yield and WUE data, the estimates of the treatment effects had greater levels of significance and precision than when the trends were ignored. It is recommended that in agronomic field trials, such as lentil variety evaluation trials, one should identify the most appropriate spatial and temporal covariance structures and use these to draw statistical inferences about the effects of agronomic input factors. Copyright © 2006 John Wiley & Sons, Ltd.
A field method for the concurrent measurement of fine sediment content and embryo survival in artificial salmonid redds
Authors: Levasseur Mylène , Bérubé Francis , Bergeron Normand E.
Published: March 2006

The infiltration cube method presented in this paper allows concurrent field measurement of fine sediment content and embryo survival in an incubating environment reproducing, as closely as possible, the morphology and grain size composition of a natural salmonid redd. An infiltration cube is made up of a rectangular (30 cm square and 20 cm high) steel frame with no walls, which has a folded plastic bag attached to its base. Each infiltration cube is buried in the substrate using a procedure aimed at reproducing, as closely as possible, the construction and morpho‐sedimentological structure of a natural salmonid redd. Using a tripod installed on the river bed or at the surface of the ice, the infiltration cube method provides a quick, easy and robust way to pull relatively large samples (approximately 65 kg) out of underwater substrate even during tough winter field conditions. The absence of walls on the cube also precludes bias in infiltration rates by both allowing lateral sediment transport within substrate and preventing loss of fine particles during retrieval from underwater. Copyright © 2006 John Wiley & Sons, Ltd.
Thermoreversible laminin‐functionalized hydrogel for neural tissue engineering
Authors: Stabenfeldt Sarah E. , García Andrés J. , LaPlaca Michelle C.
Published: March 2006

Traumatic injury to the central nervous system (CNS) triggers cell death and deafferentation, which may activate a cascade of cellular and network disturbances. These events often result in the formation of irregularly shaped lesions comprised of necrotic tissue and/or a fluid‐filled cavity. Tissue engineering represents a promising treatment strategy for the injured neural tissue. To facilitate minimally invasive delivery of a tissue engineered system, a thermoreversible polymer is an attractive scaffold candidate. We have developed a bioactive scaffold for neural tissue engineering by tethering laminin‐1 (LN) to methylcellulose (MC), a thermoresponsive hydrogel. The base MC chain was oxidized via sodium m‐periodate to increase MC tethering capacity. Protein immobilization was facilitated by a Schiff base reaction between primary amine groups on LN and the carbonyl groups of the oxidized MC chain. Immunoassays demonstrated tethering of LN at 1.6 ± 0.5 ng of LN per milligram of MC. Rheological measurements for different MC–LN constructs indicated MC composition‐ and MC treatment‐dependent effects on solution–gelation transition temperature. Cellular assays with primary rat cortical neurons demonstrated enhanced cell adhesion and viability on LN‐functionalized MC when compared with base and oxidized MC. This bioadhesive thermoresponsive scaffold may provide a robust delivery vehicle to injured CNS tissue for neural cell transplantation strategies. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Image‐guided and ‐monitored renal artery stenting using only MRI
Authors: Elgort Daniel R. , Hillenbrand Claudia M. , Zhang Shaoxiong , Wong Eddy Y. , Rafie Shervin , Lewin Jonathan S. , Duerk Jeffrey L.
Published: March 2006

Purpose

To demonstrate the ability of a unique interventional MR system to be used safely and effectively as the only imaging modality for all phases of MR‐guided stent‐supported angioplasty.

Materials and Methods

An experimental disease model of renal stenosis was created in six pigs. An interventional MR system, which employed previously reported tools for real‐time catheter tracking with automated scan‐plane positioning, adaptive image parameters, and radial true–FISP imaging with steady‐state precession (True‐FISP) imaging coupled with a high‐speed reconstruction technique, was then used to guide all phases of the intervention, including: guidewire and catheter insertion, stent deployment, and confirmation of therapeutic success. Pre‐ and postprocedural X‐ray imaging was used as a gold standard to validate the experimental results.

Results

All of the stent‐supported angioplasty interventions were a technical success and were performed without complications. The average postoperative residual stenosis was 14.9%. The image guidance enabled the stents to be deployed with an accuracy of 0.98 ± 0.69 mm. Additionally, using this interventional MRI system to guide renal artery stenting significantly reduces the procedure time, as compared to using X‐ray fluoroscopy.

Conclusion

This study has clearly demonstrated the first successful treatment of renal artery stenting in an experimental animal model solely under MRI guidance and monitoring. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
MR‐visible coatings for endovascular device visualization
Authors: Unal Orhan , Li Junwei , Cheng Weiguo , Yu Hyuk , Strother Charles M.
Published: March 2006

Purpose

To investigate the potential utility of magnetic resonance (MR)‐visible coatings for passive visualization of therapeutic endovascular devices such as catheters and guidewires.

Materials and Methods

Using a multistep coating process, gadolinium‐based coatings were applied to commercially available off‐the‐shelf catheters and guidewires. These coated devices were imaged in phantoms made of fat‐free yogurt, saline, and whole blood and also in live canine aorta on a 1.5‐T cardiovascular MR scanner using T1‐weighted two‐dimensional radiofrequency (RF)‐spoiled gradient‐recalled echo, two‐dimensional spin echo, and three‐dimensional RF‐spoiled gradient‐recalled echo techniques.

Results

Commercially available off‐the shelf catheters (4, 5, and 6 French) and guidewires (0.038 inch) were clearly visualized in all phantoms and canine aorta and the coatings proved to be durable and imageable without degradation in signal intensity up to 24 hours. MR‐visible coatings address some of the shortcomings that have previously limited the role of MR as a guidance tool.

Conclusion

Both in vitro and in vivo visualization of therapeutic endovascular devices coated with MR‐visible coatings are found to be clinically viable. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Multicontrast black‐blood MRI of carotid arteries: Comparison between 1.5 and 3 tesla magnetic field strengths
Authors: Yarnykh Vasily L. , Terashima Masahiro , Hayes Cecil E. , Shimakawa Ann , Takaya Norihide , Nguyen Patricia K. , Brittain Jean H. , McConnell Michael V. , Yuan Chun
Published: March 2006

Purpose

To compare black‐blood multicontrast carotid imaging at 3T and 1.5T and assess compatibility between morphological measurements of carotid arteries at 1.5T and 3T.

Materials and Methods

Five healthy subjects and two atherosclerosis patients were scanned in 1.5T and 3T scanners with a similar protocol providing transverse T1‐, T2‐, and proton density (PD)‐weighted black‐blood images using a fast spin‐echo sequence with single‐ (T1‐weighted) or multislice (PD‐/T2‐weighted) double inversion recovery (DIR) preparation. Wall and lumen signal‐to‐noise ratio (SNR) and wall/lumen contrast‐to‐noise ratio (CNR) were compared in 44 artery cross‐sections by paired t‐test. Interscanner variability of the lumen area (LA), wall area (WA), and mean wall thickness (MWT) was assessed using Bland‐Altman analysis.

Results

Wall SNR and lumen/wall CNR significantly increased (P < 0.0001) at 3T with a 1.5‐fold gain for T1‐weighted images and a 1.7/1.8‐fold gain for PD‐/T2‐weighted images. Lumen SNR did not differ for single‐slice DIR T1‐weighted images (P = 0.2), but was larger at 3T for multislice DIR PD‐/T2‐weighted images (P = 0.01/0.03). The LA, WA, and MWT demonstrated good agreement with no significant bias (P 0.5), a coefficient of variation (CV) of <10%, and intraclass correlation coefficient (ICC) of >0.95.

Conclusion

This study demonstrated significant improvement in SNR, CNR, and image quality for high‐ resolution black‐blood imaging of carotid arteries at 3T. Morphologic measurements are compatible between 1.5T and 3T. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Potential mechanisms for astrocyte‐TIMP‐1 downregulation in chronic inflammatory diseases
Authors: Gardner Jessica , Borgmann Kathleen , Deshpande Muralidhar S. , Dhar Alok , Wu Li , Persidsky Raisa , Ghorpade Anuja
Published: March 2006

The pathogenesis of many neurodegenerative disorders, including human immunodeficiency virus (HIV)‐1 associated dementia, is exacerbated by an imbalance between matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). In the context of disease, TIMP‐1 has emerged as an important multifunctional protein capable of regulating inflammation. We previously reported differential TIMP‐1 expression in acute versus chronic activation of astrocytes. This study investigates possible mechanisms underlying TIMP‐1 downregulation in chronic neuroinflammation. We used interleukin (IL)‐1β as a model pro‐inflammatory stimulus and measured TIMP‐1 binding to extracellular matrix, cell death, receptor downregulation, TIMP‐1 mRNA stability and transcriptional regulation in activated astrocytes. TIMP‐1 remained localized to the cell body or was secreted into the cell supernatant. DNA fragmentation ELISA and MTT assay showed that prolonged IL‐1β activation of astrocytes induced significant astrocyte death. In acute and chronic IL‐1β‐activated astrocytes, IL‐1 receptor levels were not significantly different. TIMP‐1 mRNA stability was measured in astrocytes and U87 astroglioma cells by real‐time PCR, and TIMP‐1 promoter activation was studied using TIMP‐1‐luciferase reporter constructs in transfected astrocytes. Our results indicated that TIMP‐1 expression is regulated through multiple mechanisms. Transcriptional control and loss of mRNA stabilization are, however, the most likely primary contributors to chronic downregulation of TIMP‐1. These data are important for unraveling the mechanisms underlying astrocyte responses during chronic neuroinflammation and have broader implications in other inflammatory diseases that involve MMP/TIMP imbalance. © 2006 Wiley‐Liss, Inc.
Stable expression of a neuronal dopaminergic progenitor phenotype in cell lines derived from human amniotic fluid cells
Authors: McLaughlin David , Tsirimonaki Emmanouella , Vallianatos George , Sakellaridis Nikolaos , Chatzistamatiou Theofanis , Stavropoulos‐Gioka Catherine , Tsezou Aspasia , Messinis Ioannis , Mangoura Dimitra
Published: March 2006

Cells from human amniotic fluid derived from the fetus are considered a source of multipotent cells. Their properties have not been fully exploited, partially because unlike other embryonic sources such as embryonic stem (ES) cells, cell lines from amniocentesis samples have not been generated. We have established and characterized the properties of eight individual cell lines. Flow cytometry using several cell surface markers showed that all cell lines generated consisted of homogeneous populations that lack HLAII antigenicity. Using a combination of immunocytochemistry, Western blotting, and RT‐PCR, we found weak expression of Oct4 and nestin and strong expression of tubulin‐βIII, MAP2, and tau. Specific markers for cholinergic, (nor)adrenergic, and GABAergic neurons or glia were weakly expressed or absent, whereas expression of factors implicated in early induction of dopaminergic neurons, TGF‐β3 and β‐catenin were present. Further analysis showed strong expression of EN‐1, c‐RET, PTX3, and NURR1 essential for induction and survival of midbrain dopaminergic neurons, TH, AADC, and VMAT2 components of dopamine synthesis and secretion, and syntaxin1A and SNAP‐25 necessary for neurotransmitter exocytosis. This phenotype was retained throughout passages and up to the current passage 36. Expression of neuronal and dopaminergic markers in individual AF cell lines was comparable to expression in neurons induced from ES cells and in IMR‐32 and SH‐SY5Y neuroblastomas. Our data show that cell lines can be derived from subcultures of amniocentesis, and are primarily composed of a population of progenitors with a phenotype similar to that of committed mesencephalic dopaminergic neurons. © 2006 Wiley‐Liss, Inc.
Polyethylene glycol treatment after traumatic brain injury reduces β‐amyloid precursor protein accumulation in degenerating axons
Authors: Koob Andrew O. , Borgens Richard B.
Published: March 2006

Polyethylene glycol (PEG; 2,000 MW; 30% v/v) is a nontoxic molecule that can be injected intravenously and possesses well‐documented neuroprotective properties in the spinal cord of the guinea pig. Recent studies have shown that intravenous PEG can also enter the rat brain parenchyma after injury and repair cellular membrane damage in the region of the corpus callosum. Disrupted anterograde axonal transport and resulting β‐amyloid precursor protein (APP) accumulation are byproducts of traumatic axonal injury (TAI) in the brain. APP accumulation indicates axonal degeneration as a result of axotomy, a detriment that can lead to cell death. In this study, we show that PEG treatment can eliminate APP accumulation in specific brain areas of rats receiving TAI. Six areas of the brain were analyzed: the medial cortex, hippocampus, lateral cortex, thalamus, medial lemniscus, and medial longitudinal fasciculus. Increased APP expression after injury was abolished in the thalamus and reduced in the medial longitudinal fasciculus by PEG treatment. In all remaining areas except for the lateral cortex, APP expression was not increased between injured and uninjured brains, indicating that damage was undetected in those brain areas in this study. © 2006 Wiley‐Liss, Inc.
Increased axonal mitochondrial activity as an adaptation to myelin deficiency in the Shiverer mouse
Authors: Andrews Helen , White Kathryn , Thomson Christine , Edgar Julia , Bates David , Griffiths Ian , Turnbull Douglass , Nichols Philip
Published: March 2006

Axonal pathology in multiple sclerosis (MS) has been described for over a century, but new insights into axonal loss and disability have refocused interest in this area. There is evidence of oxidative damage to mitochondrial DNA in chronic MS plaques, suggesting that mitochondrial failure may play a role in MS pathology. We propose that in the chronic absence of myelin the maintenance of conduction relies partially on an increase in mitochondria to provide energy. This increased energy requirement also promotes reactive oxygen species (ROS), because most intraaxonal ROS are generated by mitochondria. If antioxidant defenses are overwhelmed by an excess of ROS, this may result in damage to the axon. Our aim was to investigate whether a chronic lack of myelin results in adaptive changes involving mitochondria within the axon. We investigated this in the shiverer mouse. This myelin basic protein gene mutant provides a model of how adult central nervous system (CNS) axons cope with the chronic absence of a compact myelin sheath. Cytochrome c histochemistry demonstrated a twofold increase in mitochondrial activity in white matter tracts of shiverer, and electron microscopy confirmed a significantly higher number of mitochondria within the dysmyelinated axons. Our data demonstrate that there are adaptive changes involving mitochondria occurring within CNS axons in shiverer mice in response to a lack of myelin. This work contributes to our understanding of the adaptive changes occurring in response to a lack of myelin in a noninflammatory environment similar to the situation seen in chronically demyelinated MS plaques. © 2006 Wiley‐Liss, Inc.
Chronic systemic D‐galactose exposure induces memory loss, neurodegeneration, and oxidative damage in mice: Protective effects of R‐α‐lipoic acid
Authors: Cui Xu , Zuo Pingping , Zhang Qing , Li Xuekun , Hu Yazhuo , Long Jiangang , Packer Lester , Liu Jiankang
Published: March 2006

Chronic systemic exposure of D‐galactose to mice, rats, and Drosophila causes the acceleration of senescence and has been used as an aging model. However, the underlying mechanism is as yet unclear. To investigate the mechanisms of neurodegeneration in this model, we studied cognitive function, hippocampal neuronal apoptosis and neurogenesis, and peripheral oxidative stress biomarkers and also the protective effects of the antioxidant R‐α‐lipoic acid. Chronic systemic exposure of mice to D‐galactose (100 mg/kg, s.c., 7 weeks) induced a spatial memory deficit, an increase in cell karyopyknosis, apoptosis, and caspase‐3 protein levels in hippocampal neurons, a decrease in the number of new neurons in the subgranular zone in the dentate gyrus, a reduction of migration of neural progenitor cells, and an increase in death of newly formed neurons in the granular cell layer. The D‐galactose exposure also induced an increase in peripheral oxidative stress, including an increase in malondialdehyde and decreases in total antioxidative capabilities (T‐AOC), total superoxide dismutase (T‐SOD), and glutathione peroxidase (GSH‐Px) activities. A concomitant treatment with lipoic acid ameliorated cognitive dysfunction and neurodegeneration in the hippocampus and also reduced peripheral oxidative damage by decreasing malondialdehyde and increasing T‐AOC and T‐SOD, without an effect on GSH‐Px. These findings suggest that chronic D‐galactose exposure induces neurodegeneration by enhancing caspase‐mediated apoptosis and inhibiting neurogenesis and neuron migration, as well as increasing oxidative damage. In addition, D‐galactose‐induced toxicity in mice is a useful model for studying the mechanisms of neurodegeneration and neuroprotective drugs and agents. © 2006 Wiley‐Liss, Inc.
Phosphorylation of the nicotinic acetylcholine receptor in myotube‐cholinergic neuron cocultures
Authors: Lanuza Maria A. , Gizaw Rahel , Viloria Alexa , González Carmen M. , Besalduch Núria , Dunlap Veronica , Tomàs Josep , Nelson Phillip G.
Published: March 2006

Acetylcholine receptor (AChR) stability in the postsynaptic membrane is affected by serine kinases. AChR are phosphorylated by protein kinase C (PKC) and PKA, and we have shown that activation of PKA and PKC have opposite effects on AChR stability and that this may play some role in the selective, activity‐dependent synapse loss that occurs during development of the neuromuscular junction. Myotube cultures with and without added spinal motor neurons were probed with immunoaffinity‐purified antibodies prepared against phosphorylated peptides with amino acid sequences from different AChR subunits. Different treatments activating PKC (phorbol 12‐myristate 13‐acetate; PMA) or PKA (dibutyryl cyclic adenosine monophosphate; cAMP) or blocking electrical activity (tetrodotoxin; TTX) of the cocultures were chosen because of their known effects, direct or indirect, on receptor stability. We asked whether the phospho‐specific antibody staining in conjunction with α‐bungarotoxin (BTX) identification of AChR aggregates could provide a direct demonstration of changes in receptor phosphorylation produced by the treatments. We found that PMA treatment did increase phosphorylation of the delta subunit and cAMP increased phosphorylation of the epsilon subunit relative to total BTX labeling in muscle‐nerve cocultures, but not in muscle‐only cultures. Blockade of electrical activity with TTX increased the incidence of aggregates that showed no phospho‐epsilon staining. Myotube cultures grown in the absence of neurons did not show the responses of myotubes in cocultures. The results show that manipulations that alter receptor stability also produce changes in receptor phosphorylation. We suggest that phosphorylation may be a mechanism mediating the changes in receptor stability. © 2006 Wiley‐Liss, Inc.
Extinction or adaptation? Three decades of change in shifting cultivation in Sarawak, Malaysia
Authors: Hansen T. S. , Mertz O.
Published: March 2006

Shifting cultivation is commonly believed to be disappearing in Southeast Asia, but appears relatively persistent in some areas with alternative economic opportunities. This paper analyses how three decades of development have influenced both the decline and persistence of shifting cultivation in Sarawak, Malaysia. Changes in land use and demography are analysed in two Iban shifting cultivation communities, which differ in access to markets, off‐farm work, and in their proximity to large‐scale land development. Although the Sarawak State Government's policies to limit shifting cultivation have not proven effective, introduction of compulsory school attendance, investment in infrastructure and associated access to markets and employment opportunities have gradually changed local livelihoods, now composed of subsistence and commercial farming, land development and connections to local and international labour markets. Shifting cultivation of hill rice has persisted in both communities despite other economic opportunities and has been maintained for a range of reasons. However, increasing permanent migration of younger people and pressure on land from land development may gradually end shifting cultivation, particularly in more developed areas. Copyright © 2006 John Wiley & Sons, Ltd.
Sustainability under threat? The dynamics of environmental change and food production in peri‐urban Kano, northern Nigeria
Authors: Maconachie R. A. , Binns T.
Published: March 2006

In Nigeria, Africa's most populous country, peri‐urban livelihood strategies have increasingly become recognized as important survival mechanisms for a wide range of actors in the context of rapid urban population growth. Based on field research, which illuminates local actors' knowledge and perceptions of land degradation, this paper identifies some of the key forces that are currently shaping the process of peri‐urban change. The paper seeks to examine the social, economic and cultural contexts of land degradation in peri‐urban areas, with specific reference to recent developments in and around the bourgeoning city of Kano in northern Nigeria. Particular issues of concern include the competition for key resources and its impact on the environment, together with related implications for levels of poverty, livelihoods and peri‐urban food security. Since the concept of land degradation is a social construction, with different meanings for different individuals, a more critical evaluation of how the knowledge, understanding and perceptions of local actors drive behaviour and affect land‐use decisions at the micro‐level is essential if sustainable environmental policies for the future are to be initiated. Copyright © 2006 John Wiley & Sons, Ltd.
Eco‐localism and the shaping of sustainable social and natural environments in North‐East Thailand
Authors: Parnwell M. J. G.
Published: March 2006

According to Fred Curtis (2003, p. 83), ‘the road to environmental sustainability lies in the creation of local, self‐reliant, community economies’, a phenomenon he has labelled ‘eco‐localism’. Eco‐localism focuses on place‐specific responses to place‐specific challenges, set at the scale of the community, with its place‐specific history, culture, social fabric and local ecosystem. It argues the need for a local social economics, which has the capability to protect, maintain, enhance or rehabilitate local resources and environments. Curtis identifies a need to explore the means and potential for taking the eco‐localism idea from principle to practice. This paper seeks to add some empirical meat to Curtis's theoretical bones. The paper uses a case study from North‐East Thailand to describe the sequential ‘crowding out’ and ‘clawing back’ of social institutional control of local development and its social and environmental consequences. It places worsening problems of environmental degradation, resource depletion and social differentiation in the context of the dynamics of spatial integration and modern economic development. It then describes how processes of neo‐localism, congruent with recent changes in the wider Thai and international context, have been responsible for reversing a number of ecological problems and strengthening sammakee, or communal harmony, principally by means of Buddhist institutions and principles. The empirical case‐study fits very neatly with Curtis's theoretical eco‐localism construct. Copyright © 2006 John Wiley & Sons, Ltd.
Nonalcoholic fatty liver disease and liver transplantation
Authors: Angulo Paul
Published: March 2006

Nonalcoholic fatty liver disease affects a substantial proportion of the general population worldwide. This high prevalence of nonalcoholic fatty liver disease has important consequences in the donor selection process for liver transplantation, and in the posttransplant period given the high recurrence rate of disease. This paper reviews the prevalence of nonalcoholic fatty liver disease, its progressive potential, and the implications of this liver condition in both the pre- and post-liver transplantation setting.
Liver Transpl 12:523–534, 2006.

© 2006 AASLD.
Synthesis of Exfoliated Monomer Casting Polyamide 6/Na+‐Montmorillonite Nanocomposites by Anionic Ring Opening Polymerization
Authors: Liu Andong , Xie Tingxiu , Yang Guisheng
Published: March 2006

Summary: In this work, a novel method using water as a pre‐dispersant of pristine sodium montmorillonite (Na+‐MMT) and ε‐caprolactam (CL) monomer was developed for the preparation of exfoliated monomer casting polyamide 6 (MCPA6)/MMT nanocomposites via in situ anionic ring opening polymerization. The dispersion effect of MMT in the MCPA6 matrix was investigated by means of X‐ray diffraction (XRD), as well as transmission electronic microscopy (TEM). The results indicated that nanoscale dispersed MMT was successfully achieved in the MCPA6 matrix. Furthermore, the addition of a small amount of MMT dramatically improved the thermal stability of MCAP6. Analysis using differential scanning calorimetry (DSC) and XRD indicated that nanoscale dispersed MMT sheets acted as heterogeneous nucleation agents, which favored the formation of the γ‐crystalline form of the MCPA6 matrix.

MMT dispersing sketch in the course of polymerization.

magnified image

MMT dispersing sketch in the course of polymerization.
AFM Study on the Interactions Across Interfaces Containing Attached Polymer Chains
Authors: Oréfice Rodrigo L. , Clark Arthur E. , Brennan Anthony B.
Published: March 2006

Summary: Interactions between surfaces with attached polymers are very common in both biological and engineering fields. These types of interactions are critical in processes such as coagulation and flocculation in mineral processing, biological recognition in metabolic processes and stress transference in polymer composites, among others. Although many mechanisms have been proposed to explain phenomena occurring at the interfaces on a molecular level, few experimental procedures can give direct information about them. In this work, interactions occurring at interfaces containing attached polymer chains, such as the ones that are present in polymer composites, were studied by using AFM. In order to identify the effect of the structure of the interface on phenomena such as stress transference and energy dissipation, polymers with different molar mass, areal density and chemical architecture were synthesized and attached to substrates and AFM cantilevers. Force‐distance curves, obtained by AFM, provided some fundamental information about the mechanisms involved when polymers attached to different surfaces interact. Results showed that chains grafted on different surfaces can interact via entanglements and intersegmental bonding. Based upon the application of the AFM modified technique, interfaces containing polymers, such as in polymer composites, can be designed and optimized through the manipulation of its structure to achieve new roles in the performance of systems.

magnified image
Non‐Isothermal Crystallization Behavior of Poly(L‐lactic acid) in the Presence of Various Additives
Authors: Tsuji Hideto , Takai Hiroki , Fukuda Norio , Takikawa Hirofumi
Published: March 2006

Summary: The effects of various additives: poly(D‐lactic acid) (PDLA), talc, fullerene C60, montmorillonite, and various polysaccharides, on the non‐isothermal crystallization behavior of poly(L‐lactic acid) (PLLA), during both the heating of melt‐quenched films from room temperature, and the cooling of as‐cast films from the melt, was investigated. When the melt‐quenched PLLA films were heated from room temperature, the overall PLLA crystallization was accelerated upon addition of PDLA or the stereocomplex crystallites formed between PDLA and PLLA, the mixtures containing PDLA, and the mixture of talc and montmorillonite. No significant effects on the overall PLLA crystallization were observed for talc, C60, montmorillonite, and the mixtures containing C60. Such rapid completion of the overall PLLA crystallization upon addition of the aforementioned additives can be ascribed to the increased density (number per unit volume or area) of PLLA spherulites. When the as‐cast PLLA films were cooled from the melt, the overall PLLA crystallization completed rapidly, upon addition of PDLA, talc, C60, montmorillonite, and their mixtures. Such rapid overall PLLA crystallization is attributable to the increased density of the PLLA spherulites and the higher nucleation temperature for PLLA crystallization. In contrast, the addition of various polysaccharides has no significant effect, or only a very small effect, on the overall PLLA crystallization during heating from room temperature or during cooling from the melt. This finding means that the polysaccharides can be utilized as low‐cost fillers for PLLA‐based materials, without disturbing the crystallization of the PLLA. The effect of additives in accelerating the overall PLLA crystallization during cooling from the melt, decreased in the following order: PDLA > talc > C60 > montmorillonite > polysaccharides.

Polarization optical photomicrographs of pure PLLA, and the PLLA‐F film, with the fullerene additive, during cooling from the melt (Process IIB). Both of the photomicrographs were taken at 120 °C.

magnified image

Polarization optical photomicrographs of pure PLLA, and the PLLA‐F film, with the fullerene additive, during cooling from the melt (Process IIB). Both of the photomicrographs were taken at 120 °C.
Hydrolytic Degradation of Amorphous Films of L‐Lactide Copolymers with Glycolide and D‐Lactide
Authors: Saha Swapan K. , Tsuji Hideto
Published: March 2006

Summary: Films of poly(L‐lactic acid) (PLLA) and copolymers of L‐lactide (LLA) with either glycolide [P(LLA‐GA)](81/19) or D‐lactide [P(LLA‐DLA)](77/23) were prepared and an effect of comonomer type on the hydrolytic degradation of the films was studied in phosphate‐buffered solutions at 37 °C. The degraded films were investigated using gravimetry (weight loss and water absorption), gel permeation chromatography, DSC, X‐ray diffractometry, tensile testing and polarization optical microscopy. To exclude the effects of molecular weight and crystallinity on hydrolytic degradation, the films were prepared from polymers with similar molecular weights and were made amorphous by melt quenching. It was found that the hydrolytic degradation rate decreased in the order P(LLA‐GA) > P(LLA‐DLA) > PLLA. The hydrolytic degradation rate constant of PLLA and LLA copolymer films increased with increasing the water absorption (hydrophilicity), or with decreasing the initial glass transition temperature or the L‐lactyl unit sequence length, indicating that the hydrolytic degradation rate of the copolymers was closely related to these three parameters. The crystallization of P(LLA‐GA) film occurred within hydrolytic degradation for 20 weeks.

Mn of PLLA and LLA copolymer films as a function of hydrolytic degradation time.

magnified image

Mn of PLLA and LLA copolymer films as a function of hydrolytic degradation time.
Dendritic pruning of the medial amygdala during pubertal development of the male Syrian hamster
Authors: Zehr Julia L. , Todd Brigitte J. , Schulz Kalynn M. , McCarthy Margaret M. , Sisk Cheryl L.
Published: March 2006

The medial amygdala (Me), a brain region essential for mating behavior, changes in size during puberty. In pre‐, mid‐, and late pubertal (21, 35, and 49 days of age) male Syrian hamsters, we examined neuronal structure in Me and protein levels of spinophilin and synaptophysin in the amygdaloid complex for evidence of synaptic plasticity coincident with behavioral and physiological development. Body weight, testes weight, and testosterone levels increased during puberty. Mounting behavior, including ectopic, nonintromittive, and intromittive mounts, also increased. Neuronal structure in the posterodorsal medial amygdala (MePD) was assessed in Golgi‐impregnated neurons. Pruning occurred during puberty in the number of dendrites emanating from the cell body and in terminal dendritic spine densities. Approximately half of all MePD neurons analyzed had an axon emanating from a dendrite rather than the cell body. However, prepubertal males were more likely to have the axon emanating from a higher order dendritic segment (secondary or tertiary) than were mid‐ and late pubertal males. Finally, protein levels in the amygdaloid complex varied with pubertal age. Spinophilin decreased, while synaptophysin and GAPDH protein levels increased. These results suggest that puberty is a period of dramatic synaptic plasticity in Me. Specifically, pruning of dendrites and spines, in combination with axonal changes, is likely to modify the afferent influences and electrophysiological properties of Me neurons. Because the Me is an integral component of a social behavior neural network, these changes may be related not only to sexual behavior, but also to other behaviors that mature during puberty, including aggressive, risk‐taking, fear‐related, and parental behaviors. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Living with lifting: mothers' perceptions of lifting and back strain in childcare
Authors: Griffin Susan D. , Price Vikki J.
Published: March 2006

The methods a mother selects to physically care for her young children may subject her to back strain or injury depending on the methods she selects. Little is known about what motivates mothers to select particular child‐care methods and equipment. The aim of this qualitative study was to explore the choices mothers of young children make in this area and their experiences using the methods they select. Nine mothers completed a brief questionnaire and participated in a semi‐structured interview. Analysis of the data revealed a number of motivating factors that were considered before making a final decision on what method to use. Rarely were issues related to posture and back care considered. Primarily, mothers chose methods based on what was best for the child, without consideration of their own needs. Consideration of the effect of a method on their back was given only when they experienced back strain. Further research is required to investigate the best methods for lifting and handling young children while providing maximum protection for the mothers' backs. Copyright © 2000 Whurr Publishers Ltd.
Using problem‐based learning to improve educational outcomes
Authors: Watson Diane E. , West Daniel J.
Published: March 2006

As the health care industry and the occupational therapy profession experience rapid change and growth, our professional preparation and continuing education must prepare graduates and therapists for an evolving practice environment. By exploring and evaluating alternative teaching methods and their impact on educational outcomes, occupational therapy educators demonstrate their commitment to improving the quality of student education. This article proposes that the traditional educational paradigm prepared clinicians for the old health care environment, and that problem‐based learning (PBL) is an educational strategy that could prepare occupational therapists for success in a new practice environment that values cost, quality, and customer satisfaction. The PBL approaches used by various international occupational therapy educators are reviewed to highlight the strategies that have been implemented to achieve educational objectives that parallel the requirements of this new practice environment. Copyright © 1996 Whurr Publishers Ltd.
The relationship between daily occupational affective experiences and subjective well‐being
Authors: Lo Jin‐Ling
Published: March 2006

Active participation in daily occupations is one of the primary concepts of occupational therapy. In this study, 60 subjects' affective experiences in their daily occupation were compared with their subjective well‐being measures. It was found that the subjects' occupational affective experiences related significantly to their well‐being measures, especially those focusing on the affective aspect. The percentage of happy experiences was the best predictor of well‐being measures.

Active participation had a significant effect on people's well‐being, but its effect on daily occupational affective experience was not so remarkable. Implications of these results for occupational therapy are discussed. Copyright © 1996 Whurr Publishers Ltd.
Current trends in the practice of home health care of occupational therapists treating patients who have had a stroke
Authors: Moulton Christina
Published: March 2006

The present study was designed to examine current practices in home health care among occupational therapists in the United States of America treating patients who have had a stroke. On any given day an estimated 1 237 100 patients receive home health care in the USA. This makes home health care a rapidly expanding industry of the 1990s. One of the most significant populations with whom occupational therapists work are patients who have had a stroke. General guidelines for occupational therapists working in home health care include: environmental safety, motor coordination, sensory deficits, perception, cognition, ADL/IADL, and leisure activities. Two hundred surveys were sent to registered occupational therapists working in home health care in the Midwestern region of the USA. Forty‐three of the returned surveys were used in the data analysis. The results indicated that therapists are utilising an adaptive approach to treatment techniques within an eclectic frame of reference. Remedial techniques, such as Neurodevelopmental Therapy (NDT), were used often by therapists. The results also indicated that the most frequently used evaluations were standardised tests. Non‐reimbursement of services was found to be a result of the patients' insurance not covering occupational therapy services. Further research regarding psychosocial issues with this population in home health care was indicated. Copyright © 1997 Whurr Publishers Ltd.
Perception of behaviours associated with tactile defensiveness: an exploration of the differences between mothers and their children
Authors: Hotz Susan Dawn , Royeen Charlotte Brasic
Published: March 2006

The purpose of the current study was to determine whether there is a statistically significant correlation between mothers' and children's perceptions of tactile defensiveness. This investigation replicated a similar study by Bennett and Peterson (1995). The Touch Inventory for Elementary School Aged Children (TIE) was administered to 27 boys and girls, aged 8 to 11, who were selected using purposive sampling. A modified version of the TIE was given to their mothers. Results indicated that there was a statistically significant correlation (r=0.417, p=0.03) between a child's own perception of tactile defensiveness and the child's mother's perception of the child's tactile defensiveness. In general, however, the children in this study rated their perception of their own tactile defensiveness 6.5 points higher than their mothers did. The results from the current investigation are similar to those of Bennett and Peterson (1995). The children in their study rated their perception of their own tactile defensiveness 10 points higher than their mothers did. Reviewed together, these results suggest that mothers may systematically underestimate the degree of tactile defensiveness in their children, and that it is important to use information from both children and their mothers to learn more about the child's tactile defensiveness. Continued research into this area is recommended. Copyright © 1998 Whurr Publishers Ltd.
The transition through adult rites of passage after traumatic brain injury: preliminary assessment of an occupational therapy intervention
Authors: Gutman Sharon A.
Published: March 2006

A case study is presented of a 30‐year‐old male with traumatic brain injury (TBI) experiencing gender role strain. The case study describes this man's participation in an occupational therapy intervention based on social learning theory. The intervention was designed to alleviate gender role strain and to increase his ability to live independently in the community and to help him to make the transition through rites of passage leading to adulthood. At the end of the 4‐month occupational therapy intervention, the participant had achieved the adult rites of dating/courtship experiences, independent community travel and shared apartment living in the community. The data collected for this case study were intended to provide preliminary data for a subsequent study involving a greater number of participants with TBI. The case study is limited in that outcome measures used were solely qualitative self‐reports. Recommendations for future research regarding the assessment of the intervention's efficacy include expanding the number of participants and incorporating quantitative assessment tools to measure outcomes. Copyright © 1999 Whurr Publishers Ltd.
An international content validation of the Quebec User Evaluation of Satisfaction with assistive Technology (QUEST)
Authors: Demers Louise , Wessels Roelof D. , Weiss‐Lambrou Rhoda , Ska Bernadette , De Witte Luc P.
Published: March 2006

The Quebec User Evaluation of Satisfaction with assistive Technology (QUEST) is an outcome assessment tool designed to identify the sources of user satisfaction and dissatisfaction with assistive technology. This paper presents the results of an international content validation study of the QUEST that was conducted as part of the ongoing development of this assessment instrument. A questionnaire developed to measure the relevance of QUEST items and to critique the administration procedures was completed by an international group of 12 assistive technology experts from the United States, the Netherlands and Canada. At the test level, the findings revealed that the QUEST was adequately sampled in terms of embracing all the important facets of satisfaction with assistive technology. At the item level, however, it was revealed that changes needed to be made to the wording of the satisfaction variables and to the administration procedures for the QUEST in order to ensure optimal content validity. A limitation of the study is the heterogeneity of the testing sites that may have reduced the chances of reaching consensual agreement among the content experts. It is recommended that future studies consider alternative methods such as factorial analysis to support the findings of this study. Copyright © 1999 Whurr Publishers Ltd.
Critical companionship: our learning journey
Authors: Gribben Bernadette , Cochrane Clare
Published: March 2006

In the current climate of increasing work pressures, nurses have been exploring a variety of approaches that will provide a supportive environment while addressing their own development needs. The nursing profession has become increasingly interested in the concept of facilitated reflective practice (Department of Health, 1993) to provide this supportive environment. The more widely recognized strategies that have been adopted include clinical supervision, critical mentorship and action learning. A relatively new approach has been developed called critical companionship, which is described by Angie Titchen (2001) as

a metaphor for a helping relationship in which a critical companion accompanies a less experienced practitioner on their personal experiential learning journey.

This paper outlines how two colleagues, Bernadette and Clare, developed their working relationship and facilitation skills in an environment of support and challenge using this framework. Copyright © 2006 John Wiley & Sons, Ltd.
C‐terminal sequencing method for proteins in polyacrylamide gel by the reaction of acetic anhydride
Authors: Miyazaki Kenji , Tsugita Akira
Published: March 2006

A successive C‐terminal amino acid truncation reaction with acetic anhydride was applied on proteins in polyacrylamide gel. Protein bands separated by conventional SDS‐PAGE were excised, partially fixed in the gel with glutaraldehyde ethanol solution, dehydrated with ACN and subjected to the truncation reaction with acetic anhydride formamide solution. Pre‐treatment of the gel with pyridine aqueous solution was found to enhance the truncation reaction yields. After the truncation reaction, the products were treated with an aqueous solution of dimethylaminoethanol to hydrolyze oxazolone rings at the C termini of the truncated products and O‐acetylated products of serine, threonine and/or tyrosine. Several commercially available proteins of 10–40 kDa, as determined by SDS‐PAGE, such as myoglobin, trypsin inhibitor, α‐hemolysin, cytochrome c, chymotrypsin C chain, elastase, acylase and histone H4, were subjected to the C‐terminal analysis. The truncated proteins were in‐gel digested with trypsin and the extracted peptides were analyzed by MALDI‐TOF MS, giving rise to a series of molecular mass ions of the C‐terminal truncated fragments corresponding to the C‐terminal amino acid sequence of the relevant protein.
A functional proteomics approach for the detection of nuclear proteins based on derepressed importin alpha
Authors: Blazek Erik , Meisterernst Michael
Published: March 2006

The identification of functional proteomes is a major challenge in proteomic research. Here we describe a method for the detection and isolation of nuclear (localization sequence containing) proteins using a derepressed import receptor (DIRE) as a synthetic antibody. We demonstrate that the DIRE method specifically detects nuclear localization sequence containing proteins. Application to activation of primary T‐lymphocytes exemplifies the potential use of DIRE for comparative proteomics and for diagnostics.