bluuebunny/crossref_metadata_2025 huggingface dataset:
The isthmic neuroepithelium is essential for cerebellar midline fusion
Authors: Louvi Angeliki , Alexandre Paula , Métin Christine , Wurst Wolfgang , Wassef Marion
Published: September 2003

The cerebellum comprises a medial domain, called the vermis, flanked by two lateral subdivisions, the cerebellar hemispheres. Normal development of the vermis involves fusion of two lateral primordia on the dorsal midline. We investigated how the cerebellum fuses on the midline by combining a study of mid/hindbrain cell movements in avian embryos with the analysis of cerebellar fusion in normal and mutant mouse embryos. We found that, in avian embryos,divergent cell movements originating from a restricted medial domain located at the mid/hindbrain boundary produce the roof plate of the mid/hindbrain domain. Cells migrating anteriorly from this region populate the caudal midbrain roof plate whereas cells migrating posteriorly populate the cerebellar roof plate. In addition, the adjacent paramedial isthmic neuroepithelium also migrates caudalward and participates in the formation of the cerebellar midline region. We also found that the paramedial isthmic territory produces two distinct structures. First, the late developing velum medullaris that intervenes between the vermis and the midbrain, and second, a midline domain upon which the cerebellum fuses. Elimination or overgrowth of this isthmic domain in Wnt1sw/sw and En1+/Otx2lacZ mutant mice, respectively, impair cerebellar midline fusion. Because the isthmus-derived midline cerebellar domain displays a distinct expression pattern of genes involved in BMP signaling, we propose that the isthmus-derived cells provide both a substratum and signals that are essential for cerebellar fusion.
Mouse placenta is a major hematopoietic organ
Authors: Alvarez-Silva Marcio , Belo-Diabangouaya Patricia , Salaün Josselyne , Dieterlen-Lièvre Françoise
Published: September 2003

Placenta and yolk sac from 8- to 17-day-old (E8-E17) mouse embryos/fetuses were investigated for the presence of in vitro clonogenic progenitors. At E8-E9, the embryonic body from the umbilicus caudalwards was also analysed. Fetal liver was analysed beginning on E10. At E8, between five and nine somite pairs (sp), placenta, yolk sac and embryonic body yielded no progenitors. The first progenitors appeared at E8.5 at the stage of 15 sp in the yolk sac, 18 sp in the embryonic body, 20 sp in the placenta and only at E12 in the fetal liver (absent at E10, at E11 not determined). Progenitors with a high proliferation potential that could be replated for two months, as well as the whole range of myeloid progenitors, were found at all stages in all organs. However, the earliest of these progenitors (these yielding large, multilineage colonies) were 2-4 times more frequent in the placenta than in the yolk sac or fetal liver. In the fetal liver, late progenitors were more frequent and the cellularity increased steeply with developmental age. Thus, the fetal liver,which is a recognized site for amplification and commitment, has a very different hematopoietic developmental profile from placenta or yolk sac. Placentas were obtained from GFP transgenic embryos in which only the embryonic contribution expressed the transgene. 80% of the colonies derived from these placental cells were GFP+, and so originated from the fetal component of the placenta. These data point to the placenta as a major hematopoietic organ that is active during most of pregnancy.
Egfr signaling regulates ommatidial rotation and cell motility in theDrosophilaeye via MAPK/Pnt signaling and the Ras effector Canoe/AF6
Authors: Gaengel Konstantin , Mlodzik Marek
Published: September 2003

Epidermal Growth Factor-receptor (Egfr) signaling is evolutionarily conserved and controls a variety of different cellular processes. In Drosophila these include proliferation, patterning, cell-fate determination, migration and survival. Here we provide evidence for a new role of Egfr signaling in controlling ommatidial rotation during planar cell polarity (PCP) establishment in the Drosophila eye. Although the signaling pathways involved in PCP establishment and photoreceptor cell-type specification are beginning to be unraveled, very little is known about the associated 90° rotation process. One of the few rotation-specific mutations known is roulette (rlt) in which ommatidia rotate to a random degree, often more than 90°. Here we show that rlt is a rotation-specific allele of the inhibitory Egfr ligand Argos and that modulation of Egfr activity shows defects in ommatidial rotation. Our data indicate that, beside the Raf/MAPK cascade, the Ras effector Canoe/AF6 acts downstream of Egfr/Ras and provides a link from Egfr to cytoskeletal elements in this developmentally regulated cell motility process. We provide further evidence for an involvement of cadherins and non-muscle myosin II as downstream components controlling rotation. In particular, the involvement of the cadherin Flamingo, a PCP gene, downstream of Egfr signaling provides the first link between PCP establishment and the Egfr pathway.
Priority-setting and hospital strategic planning: a qualitative case study
Authors: Martin Douglas , Shulman Ken , Santiago-Sorrell Patricia , Singer Peter
Published: September 2003

Objectives: To describe and evaluate the priority-setting element of a hospital's strategic planning process.

Methods: Qualitative case study and evaluation against the conditions of 'accountability for reasonableness' of a strategic planning process at a large urban university-affiliated hospital.

Results: The hospital's strategic planning process met the conditions of 'accountability for reasonableness' in large part. Specifically: the hospital based its decisions on reasons (both information and criteria) that the participants felt were relevant to the hospital; the number and type of participants were very extensive; the process, decisions and reasons were well communicated throughout the organization, using multiple communication vehicles; and the process included an ethical framework linked to an effort to evaluate and improve the process. However, there were opportunities to improve the process, particularly by giving participants more time to absorb the information relevant to priority-setting decisions, more time to take difficult decisions and some means to appeal or revise decisions.

Conclusion: A case study linked to an evaluation using 'accountability for reasonableness' can serve to improve priority-setting in the context of hospital strategic planning.
Variation in unit costs of hospitals in the English National Health Service
Authors: Jacobs Rowena , Dawson Diane
Published: September 2003

Objectives: In England, the Department of Health places high priority on reducing the variation in unit costs of National Health Service (NHS) hospitals. Efficiency targets are set for hospitals to create incentives for relatively high cost hospitals to reduce their costs and shift performance closer to that of their lower cost counterparts. We examine empirically the dispersion in unit costs to assess the extent of variation in the productivity of hospitals and trends over time.

Methods: We use econometric panel data techniques on data from 235 NHS acute hospital trusts over a six-year period, 1994/95 to 1999/00, supplemented with information from semi-structured interviews with key individuals in hospitals and purchasing bodies.

Results: There appears to have been no reduction in variation during this period. Relative unit costs for individual trusts also appear stable, with little movement from relatively high cost to low cost. Judging from limited quantitative evidence outside health care, the variation in costs between NHS hospitals may be comparatively low.

Conclusions: Given all the other aspects of hospital performance that government is seeking to change, reduction in the dispersion of unit costs per se should not be a major policy objective. It is far more important to examine variation in quality-adjusted unit costs.
Conspicuous consumption: characterizing high users of physician services in one Canadian province
Authors: Reid Robert , Evans Robert , Barer Morris , Sheps Samuel , Kerluke Kerry , McGrail Kimberlyn , Hertzman Clyde , Pagliccia Nino
Published: September 2003

Objectives: To examine medical care use and costs, patterns of morbidity and co-morbidity, and other patient characteristics of high users of physician services in British Columbia.

Methods: This population-based study uses physician claims, hospital discharge summaries and vital statistics data linked at the level of the individual to compare characteristics of high users, other users and non-users of physician services in the Province of British Columbia, Canada. The study included all enrolled adults in the universal health care plan during fiscal year 1996/97. High users were defined as the most costly 5% of users of fee-reimbursed services. Key variables included age, sex, an ecological socio-economic status indicator and a comprehensive set of morbidity indicators, derived from the diagnoses recorded on the utilization records.

Results: The top 5% of users consumed a disproportionate 30% of spending on physician services. High users were overwhelmingly characterized by a significant burden of morbidity. Over 80% had at least six different types of morbidity during the study year compared with fewer than 20% of other users. High users were also much more likely to have major diagnoses that were both acute and chronic in nature. Co-morbidity involving psychosocial and chronic medical conditions was also very common.

Conclusions: High users of physician services are overwhelmingly characterized by multiple and complex health problems. Policy tools based on a philosophy of deterrence such as cost-sharing are unlikely to have much impact on their costs and will likely do considerable harm.
Beyond demographic change in human resources planning: an extended framework and application to nursing
Authors: Birch Stephen , O'Brien-Pallas Linda , Alksnis Chris , Tomblin Murphy Gail , Thomson Donna
Published: September 2003

Objectives: To introduce health care production functions into human resources planning and to apply the approach to analysing the need for registered nurses in Ontario during a period of major reduction in inpatient capacity.

Methods: Measurement of changes in services delivered by acute care hospitals in Ontario between 1994/95 and 1998/99, and comparison with changes in the mix of human resources, non-human resources and patient needs.

Results: Inpatient episodes per nurse fell by almost 2%. At the same time the number of beds was cut by over 20%. As a result, the number of patients per bed increased by 12%. Allowing for severity, there was a 20% reduction in beds per episode and a 3.7% reduction in nurses per episode.

Conclusions: The demands on nurses in acute care hospitals have increased as an increasing number of severity-adjusted episodes are served using fewer beds by a reduced number of nurses. Human resources planning traditionally only considers the effects of demographic change on the need for and supply of health care. Failure to recognize the variable and endogenous nature of other health care inputs leads to false impressions about the adequacy of existing supplies of human resources. Consideration of human resources in the context of the production function for health services provides a meaningful way of improving the effectiveness and efficiency of human resources planning.
Efficiency and productivity change in the English National Health Service: can data envelopment analysis provide a robust and useful measure?
Authors: Hollingsworth Bruce , Parkin David
Published: September 2003

Objective: Several tools are available to health care organisations in England to measure efficiency, but these are widely reported to be unpopular and unusable. Moreover, they do not have a sound conceptual basis. This paper describes the development and evaluation of a user-friendly tool that organisations can use to measure their efficiency, based on the technique of data envelopment analysis (DEA), which has a firm basis in economic theory.

Methods: Routine data from 57 providers and 14 purchasing organisations in one region of the English National Health Service (NHS) for 1994-1996 were used to create information on efficiency based on DEA. This was presented to them using guides that explained the information and how it was to be used. They were surveyed to elicit their views on current measures of efficiency and on the potential use of the DEA-based information.

Results: The DEA measure demonstrated considerable scope for improvements in health service efficiency. There was a very small improvement over time with larger changes in some hospitals than others. Overall, 80% of those surveyed gave high scores for the potential usefulness of the DEA-based measures compared with 9-45% for existing methods. The quality of presentation of the information was also consistently high.

Conclusions: There is dissatisfaction with efficiency information currently available to the NHS. DEA produces potentially useful information, which is easy to use and can be easily explained to and understood by potential users. The next step would be the implementation, on a developmental basis, of a routine DEA-based information system.
The economics of direct-to-consumer advertising of prescription-only drugs: prescribed to improve consumer welfare?
Authors: Morgan Steven , Mintzes Barbara , Barer Morris
Published: September 2003

According to economic theory, one might expect that the informational content of direct-to-consumer advertising of prescription-only drugs would improve consumers' welfare. However, contrasting the models of consumer and market behaviour underlying this theory with the realities of the prescription-only drug market reveals that this market is distinct in ways that render it unlikely that advertising will serve an unbiased and strictly informative function. A review of qualitative evidence regarding the informational content of drug advertising supports this conclusion. Direct-to-consumer prescription drug advertising concentrates on particular products, and features of those products, to the exclusion of others, and the information provided has frequently been found to be biased or misleading in regulatory and academic evaluations. Governments that have so far resisted direct-to-consumer advertising should invest in independent sources of evidence that could help consumers and professionals to better understand the risks and benefits of treating disease with alternative drug and non-drug therapies, rather than permitting direct-to-consumer prescription drug advertising.
Linkage and exchange at the organizational level: A model of collaboration between research and policy
Authors: Goering Paula , Butterill Dale , Jacobson Nora , Sturtevant Darryl
Published: October 2003

This paper describes an organization-level initiative designed to promote linkage and exchange between a research unit and the mental health policy branch of Ontario's provincial government. Using a framework that conceptualizes four tiers – inter-organizational relationship, interactive research projects, dissemination and policy formation – in the application of linkage and exchange to the research and policy development processes, we present an example in order to explore the issues that arise in each tier. We conclude that while such initiatives enhance the relevance of research in the policy development process, they also present challenges that must be recognized and managed.
Estradiol in Severe Asthma with Premenstrual Worsening
Authors: Ensom Mary HH , Chong Gina , Beaudin Bev , Bai Tony R
Published: October 2003

OBJECTIVE:

To describe the beneficial effects of estradiol in a severely asthmatic woman with premenstrual worsening of asthma.

CASE SUMMARY:

A 50-year-old white woman, with a 14-year history of severe steroid-dependent asthma and monthly premenstrual worsening of asthma, was randomized to receive estradiol 2 mg or placebo for 6 days during the late luteal phase (days 23–28) of 2 successive menstrual cycles. Despite greater prednisone and inhaled β-agonist use during the late luteal phase of the placebo cycle, the patient exhibited improved asthma symptoms, pulmonary function, and peak expiratory flows, as well as lower values for biomarkers of airway inflammation during the same time period of the estradiol cycle.

DISCUSSION:

This subject's response to estradiol was in contrast to results of a randomized, controlled trial involving patients with predominantly mild asthma under excellent control. The discrepant observations for this case versus the majority of subjects in the randomized, controlled study suggest that premenstrual asthma (PMA) and a beneficial response to estradiol may be more likely in women with severe asthma.

CONCLUSIONS:

The administration of estradiol during the late luteal phase of the menstrual cycle to a woman with severe asthma with PMA was associated with improved asthma symptoms, pulmonary function, and peak expiratory flows, and lower serum eosinophil protein X and urinary leukotriene E4 biomarker concentrations. Thus, estradiol's potential role in women with severe asthma and PMA may warrant further exploration in this subgroup.
Revisiting emulsion polymerization to produce stable, translucent, nanolatex of partially water‐soluble monomers, ethylacrylate–methylmethacrylate
Authors: Bhawal Sumit , Dhoble Deepa , Devi Surekha
Published: September 2003

Stable, translucent nanolatex with monomer weight % as high as 25 was obtained through emulsion copolymerization of partially water‐soluble monomers, ethyl acrylate and methylmethacrylate. The kinetics of reaction, studied at monomer/surfactant (M/S) ratio 10 and 50 showed two intervals and higher rate of particle nucleation for KPS initiated systems. However, AIBN initiated system showed phase separation. The copolymer composition was determined through 1H‐NMR studies and copolymers showed two glass transition temperatures. Dynamic light scattering studies indicated bimodal distribution of polymer particle size. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2593–2603, 2003
Mechanical properties and structures of dicyanate–clay nanocomposites
Authors: Kim Dae Su , Lee Kyung Min
Published: September 2003

Dicyanate–clay nanocomposites comprising a dicyanate resin and a type of organically modified clay were prepared and characterized, and their thermomechanical properties were investigated. The organically modified clay had silicate layers of nanometer size intercalated with an organic modifier, which improved the compatibility between the clay and organic materials, such as dicyanate resins. Dynamic mechanical analysis was performed to investigate the thermomechanical properties of the dicyanate–clay nanocomposites containing various amounts of the clay. The storage modulus of the nanocomposites below their glass‐transition temperatures slightly increased with increasing clay content. The glass‐transition temperature of the dicyanate–clay nanocomposites increased with increasing clay content. The nanostructures of the dicyanate–clay nanocomposites were characterized by transmission electron microscopy and X‐ray diffraction analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2629–2633, 2003
Synthesis and characterization of conducting homopolymers and copolymers of o‐anisidine and o‐toluidine in inorganic and organic supporting electrolytes
Authors: Borole D. D. , Kapadi U. R. , Mahulikar P. P. , Hundiwale D. G.
Published: September 2003

The influence of inorganic and organic supporting electrolytes on the electrochemical, optical, and conducting properties of poly(o‐anisidine), poly(o‐toluidine), and poly(o‐anisidine‐co‐o‐toluidine) thin films was investigated. Homopolymer and copolymer thin films were synthesized electrochemically, under cyclic voltammetry conditions, in aqueous solutions of inorganic acids (H2SO4, HCl, HNO3, H3PO4, and HClO4) and organic acids (benzoic acid, cinnamic acid, oxalic acid, malonic acid, succinic acid, and adipic acid) at room temperature. The films were characterized by cyclic voltammetry, ultraviolet–visible spectroscopy, and conductivity measurements with a four‐probe technique. The ultraviolet–visible spectra were obtained ex situ in dimethyl sulfoxide. The optical absorption spectra indicated that the formation of the conducting emeraldine salt (ES) phase took place in all the inorganic electrolytes used, whereas in organic acid supporting electrolytes, ES formed only with oxalic acid. Moreover, the current density and conductivity of the thin films was greatly affected by the nature and size of the anion present in the electrolyte. For the copolymer, the conductivity lay between the conductivity of the homopolymers, regardless of the supporting electrolyte used. The formation of the copolymer was also confirmed with differential scanning colorimetry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2634–2642, 2003
Evolution of properties with increasing cure of a thermosetting epoxy/aromatic amine system: Physical ageing
Authors: Lee Jong Keun , Gillham John K.
Published: September 2003

Isothermal physical ageing below the glass‐transition temperature (Tg) of a high‐Tg thermosetting difunctional epoxy/tetrafunctional aromatic amine system was investigated at different ageing temperatures (Ta) and chemical conversions (monitored by the Tg) using the torsional braid analysis freely oscillating torsion pendulum technique. In the absence of chemical reaction during an isothermal ageing process, the rate of isothermal physical ageing passes through a minimum with increasing conversion. The minimum is related to the minimum in mechanical loss between the secondary relaxation in the glassy state (Tβ) and the glass‐transition relaxation (Tg) (the temperatures of both of which increase with increasing conversion). If isothermal ageing rates for all conversions (beyond gelation) would have been measured directly from temperatures below Tβ to above Tg, it is concluded that two maxima in isothermal ageing rate would have been observed corresponding to the two relaxation processes. There exists a superposition in isothermal ageing rate versus Tg − Ta [by shifting horizontally (and vertically)], which implies that the ageing rate is independent of the details of the changing chemical structure attributed to cure. Controlling mechanisms during physical ageing are segmental mobility associated with the Tg region and more localized motion associated with the glassy‐state relaxation Tβ. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2665–2675, 2003
Influence of the nature and the content of carbon fiber on properties of thermoplastic polyurethane‐carbon fiber composites
Authors: Sánchez‐Adsuar M. S. , Linares‐Solano A. , Cazorla‐Amorós D. , Ibarra‐Rueda L.
Published: September 2003

Three carbon fibers (CF) of different characteristics and properties were used to determine the most suitable characteristics for a carbon fiber to reinforce a thermoplastic polyurethane elastomer (TPU) matrix. The TPU was synthesized with a moderate amount of hard segments to bring polarity to the matrix without losing flexibility. On the other hand, the CF were chosen with respect to their different mechanical properties, diameter, and length to study the influence of those parameters on the TPU matrix. Additionally, the fibers were used in different amounts as well as after different oxidation treatments (i.e., different polarity). The mechanical properties and surface characteristics of the composites were analyzed using several experimental techniques (SEM, X‐ray photoelectron spectroscopy, dynamic mechanical thermal analysis, and tensile tests). The results obtained showed that the surface polarity, diameter, and length of the CFs are related to the reinforcement of a medial polar TPU matrix, whereas the mechanical properties of the CF do not influence those of the composite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2676–2683, 2003
Polymer supported synthesis of mixed ligand complexes
Authors: Chacko Sheela , Mathew Tessymol , Kuriakose Sunny
Published: September 2003

A series of novel polymer‐supported mixed ligand complexes were synthesized and studied. Two percent divinyl benzene (DVB)‐crosslinked polystyrene supports were synthesized by the suspension copolymerization technique. An ethylene diamine group was anchored onto the support and the corresponding copper complexes were prepared. The ligating functions like phthalate, acetate, and oxalate groups were introduced, and mixed ligands complexes were synthesized. The resultant polymer supported mixed ligand complexes were characterized by UV‐Vis, IR, and EPR methods. The stability constants dictate the formation of these complexes on polymer support. Spectral results gave information about the structure, stability, and geometry of the mixed ligand complexes. These factors were discussed in detail. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2684–2690, 2003
Affect of dope additives on finishing behavior of carbon fiber precursors
Authors: Hou Chen , Wang Cheng‐Guo , Ying Liang , Cai Hua‐Su
Published: September 2003

Finishing kinetics of acrylic precursor fibers was studied by using a new CGB finish. Effects of dope additives including polyvinyl pyrrolidone, glycerol, and polyvinyl acetate on finishing behavior of acrylic precursors were contrastively discussed. Diffusion coefficients for the finish were calculated from the Crank's equation. It is shown that the precursor fibers applied with the CGB finish do not give fluffs, broken, and adhered precursors. The increase of the finish uptake values is greater around the glass transition temperature, and the changes of uptake become less prominent as the finish bath temperature above the glass transition temperature. By use of the dope additives, the finish uptake values are enhanced; the diffusion coefficient for the finish is higher; the activation energy required for the finish is lower; the extent being greatest for the fibers containing polyvinyl pyrrolidone. The properties of the finished precursor fibers containing polyvinyl pyrrolidone are the best. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2752–2755, 2003
Photoplastic effect in polycarbonate using tensile deformation
Authors: Sharma Sandhya , Bajpai R. , Chandra B.P.
Published: September 2003

The studies on photoplastic effect of polycarbonate has helped significantly in understanding the elastoplastic behavior of polycarbonate. When a plastically deformed specimen (polcarbonate) is suddenly illuminated with light of proper wavelength, a decrease in flow stress is observed, deformation leads to the softening, of specimen, i.e., to the negative photoplastic effect obtained at room temperature. On switching off, deformation stress reaches its level in the dark. The studies on the negative photoplastic effect mechanism can offer ways to control the properties of photoelectronic devices. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2703–2707, 2003
A novel biodegradable antimicrobial PU foam from wattle tannin
Authors: Ge Jinjie , Shi Xinghai , Cai Meiqin , Wu Rui , Wang Min
Published: September 2003

A new kind of polyurethane (PU) foam was synthesized from wattle tannin (WT), which has good prospects of application for its biodegradation and bacteriostasis. The effects of WT content, diisocyanate dosage, and chemical modification of WT on properties of PU were investigated. It was found that WT could contribute not only to bacteriostatic activity, but also to biodegradability during soil micro‐organism treatment for the polyurethane foams. Furthermore, the bacteriostasis of PU is improved by modifying the chemical structure of WT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2756–2763, 2003
Permeability of semicrystalline polymers to toluene/methanol mixture
Authors: Gagnard Christelle , Germain Yves , Keraudren Patrick , Barrière Benoît
Published: September 2003

In this article, we analyze the effect of the alcohol content in gasoline on the permeability of four semicrystalline polymers used in automobile fuel systems. More specifically, we are interested in the methanol/toluene mixture as a “binary” model of a complex gasoline to understand the selectivity brought about, in front of these solvents, by the nature of the polymer. We developed a permeation cell coupled to a chromatograph to analyze the composition of escaping toluene and methanol. These experiments allow us to demonstrate the strong “positive synergy” that exists between the flows of the methanol and the toluene when they are mixed, compared to the flows of these solvents on their own. This phenomenon is notably highlighted on polymers of very different kinds (PA12, PVDF, HDPE, EVOH) and, in light of recent theoretical developments, we can consider that this property is general, because this “positive synergy” is a consequence of the evolution of the solubility of the mixture of solvents in the polymer film, and more particularly, of the highly positive value of the Flory‐Huggins interaction coefficient between methanol and toluene. These experimental data allow one to better understand and predict the permeability behavior of the polymers in front of complex gasolines. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2727–2733, 2003
Comparison between the thermal and microwave curing of bismaleimide resin
Authors: Zainol Ismail , Day Richard , Heatley Frank
Published: September 2003

Microwave energy was used to cure Matrimid 5292A bismaleimide resin. The degree of cure at different cure times was determined with differential scanning calorimetry. A comparison was made with the same resin cured in a conventional oven. The resin cured faster in the microwave oven than in the conventional oven. The glass‐transition temperature (Tg) depended on the degree of cure. The samples cured with a conventional oven showed slightly higher Tg's than the microwave‐cured samples at higher degrees of cure. At low degrees of cure, the two heating methods yielded materials with similar Tg's. Fourier transform infrared spectroscopy and solid‐state cross‐polarity/magic‐angle‐spinning 13C NMR spectroscopy were used to investigate the cured structures. There was no difference in the chemical reactions taking place during the microwave cure and the thermal cure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2764–2774, 2003
Effect of plasticizers in poly(vinyl alcohol)‐based hybrid solid polymer electrolytes
Authors: Rajendran S. , Sivakumar M. , Subadevi R.
Published: September 2003

Hybrid solid polymer electrolyte films consisting of poly(vinyl alcohol) (PVA), poly(methyl methacrylate) (PMMA), LiBF4, and ethylene carbonate/propylene carbonate (EC/PC) were prepared with a solvent‐casting technique. The complexation was investigated with Fourier transform infrared and X‐ray diffraction. The ionic conductivities of the electrolyte films were determined with an alternating‐current impedance technique for various temperatures in the range of 302–373 K. The maximum conductivity value, 1.2886 × 10−3 S/cm, was observed for a PVA–PMMA–LiBF4–EC complex. Thermogravimetry/differential thermal analysis was performed to ascertain the thermal stability of the electrolyte with the maximum conductivity value. For an examination of the cyclic and reversible performance of the film, a cyclic voltammetry study was carried out. The surface morphology of the EC‐and PC‐based electrolytes was examined with scanning electron microscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2794–2800, 2003
Effect of the crosslinking degree on curing kinetics of an epoxy–acid copolymer system
Authors: Heba F. , Mouzali M. , Abadie M. J. M.
Published: September 2003

The hardening of a commercial epoxy resin (DGEBA) with the cure of high molecular weight acid copolymers was studied using differential scanning calorimetry (DSC). The systems were uncured and partially cured epoxy/poly(acrylic acid–styrene) (SAAS), at different contents of styrene. The conversion degree of the crosslinking of the systems, examined versus time, temperature of hardening, and styrene contents in the copolymers, were determined. The activation energies of the crosslinking reactions were calculated by the Freeman–Carrol relation and showed a dependence on the state of hardening. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2834–2839, 2003
Preparation and characterization of titanium oxide‐densified cellulose beads for expanded bed adsorption
Authors: Lei Yin‐Lin , Lin Dong‐Qiang , Yao Shan‐Jing , Zhu Zi‐Qiang
Published: September 2003

Expanded bed adsorption (EBA) has been widely used in industrial downstream bioprocessing. Solid matrix is the principal pillar supporting the successful application of the EBA. A new type of TiO2‐densified cellulose beads as matrix for EBA is exploited through the method of water‐in‐oil suspension thermal regeneration. The typical physical properties of beads are wet density 1.21 g/cm3, specific surface area 38.7 m2/mL, porosity 83.7%, and water content 69.5%. The results indicate that the custom‐assembled matrix can be derivated to function as an anion exchanger for EBA, by possessing a significant mechanical strength, stable hydrodynamics, and comparable protein breakthrough capacities with the commercial Streamline diethylaminoethyl (DEAE) adsorbent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2848–2854, 2003
Polymerization of 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione with diisocyanates
Authors: Mallakpour Shadpour , Rafiee Zahra
Published: September 2003

4‐(4′‐Aminophenyl)‐1,2,4‐triazolidine‐3,5‐dione (1) was reacted with 1,8‐naphthalic anhydride (2) in a mixture of acetic acid and pyridine (3 : 2) under refluxing temperature and gave 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione (NIPTD) (3) in high yield and purity. The compound NIPTD was reacted with excess n‐propylisocyanate in N,N‐dimethylacetamide solution and gave 1‐(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐triazolidine‐3,5‐dione (4) and 1,2‐bis(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐ triazolidine‐3,5‐dione (5) as model compounds. Solution polycondensation reactions of monomer 3 with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and tolylene‐2,4‐diisocyanate (TDI) were performed under microwave irradiation and conventional solution polymerization techniques in different solvents and in the presence of different catalysts, which led to the formation of novel aliphatic‐aromatic polyureas. The polycondensation proceeded rapidly, compared with conventional solution polycondensation, and was almost completed within 8 min. These novel polyureas have inherent viscosities in a range of 0.06–0.20 dL g−1 in conc. H2SO4 or DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2861–2869, 2003
Development of the larval nervous system of the gastropod Ilyanassa obsoleta
Authors: Dickinson Amanda J.G. , Croll Roger P.
Published: September 2003

Gastropods have been well studied in terms of early cell cleavage patterns and the neural basis of adult behaviors; however, much less is known about neural development in this taxon. Here we reveal a relatively sophisticated larval nervous system in a well‐studied gastropod, Ilyanassa obsoleta. The present study employed immunocytochemical and histofluorescent techniques combined with confocal microscopy to examine the development of cells containing monoamines (serotonin and catecholamine), neuropeptides (FMRFamide and leu‐enkephalin related peptides), and a substance(s) reactive to antibodies raised against dopamine beta‐hydroxylase. Neurons were first observed in the apical organ and posterior regions during the embryonic trochophore stage. During later embryonic development neurons appeared in peripheral regions such as the foot, velum, and mantle and in the developing ganglia destined to become the adult central nervous system. In subsequent free‐swimming veliger stages the larval nervous system became increasingly elaborate and by late larval stages there existed ∼26–28 apical cells, 80–100 neurons in the central ganglia, and 200–300 peripherally located neurons. During metamorphosis some populations of neurons in the apical organ and in the periphery disappeared, while others were incorporated into the juvenile nervous system. Comparisons of neural elements in other molluscan larvae reveal several similarities such as comparable arrangements of cells in the apical organ and patterns of peripheral cells. This investigation reveals the most extensive larval nervous system described in any mollusc to date and information from this study will be useful for future experimental studies determining the role of larval neurons and investigations of the cellular and molecular mechanisms governing neural development in this taxon. J. Comp. Neurol. 466:197–218, 2003. © 2003 Wiley‐Liss, Inc.
Parcellation of cortical afferents to three distinct sectors in the parahippocampal gyrus of the rhesus monkey: An anatomical and neurophysiological study
Authors: Blatt Gene J. , Pandya Deepak N. , Rosene Douglas L.
Published: September 2003

The posterior parahippocampal gyrus (PHG) of the rhesus monkey (Macaca mulatta) is comprised of three distinct cortical areas based on cytoarchitecture, connectivity, and neurophysiological response properties. Fluorescent retrograde tracers placed in each PHG area demonstrated unique patterns of cortical afferent input to areas TH, TL, and TF. Area TF receives inputs from the multimodal cortices of the superior temporal sulcus including areas PGa, TPO, and MST, from the visuospatial parietal area PG‐Opt, and from visual areas V3A and dorsal V4. Area TL receives afferents from the inferotemporal region including visual areas TE1 and TE2 as well as from areas TEa, IPa, and FST in the lower bank and depth of the superior temporal sulcus. In contrast, the input to area TH is from the rostral part of superior temporal gyrus, including the auditory association areas TS1‐3, and from the middle sector of area TPO in the superior temporal sulcus. Frontal and cingulate areas also project to the PHG in largely differential patterns. To further investigate this a correlative electrophysiological study of the three PHG areas resulted in a confirmation of these differential cortical inputs such that visually responsive neurons were found in areas TF and TL, auditory responsive neurons or bimodal auditory/visual‐responsive neurons in area TH, and somatosensory‐responsive neurons at the TF/TL border. Since each PHG area also receives differential hippocampal input, these data suggest that the processing of unimodal or multimodal information may be related to memory processing functions that are largely segregated within areas TH, TL, and TF. J. Comp. Neurol. 466:161–179, 2003. © 2003 Wiley‐Liss, Inc.
Morphological analysis of disabled‐1‐immunoreactive amacrine cells in the guinea pig retina
Authors: Lee Eun‐Jin , Kim Hyun‐Ju , Kim In‐Beom , Park Jae‐Hyung , Oh Su‐Ja , Rickman Dennis W. , Chun Myung‐Hoon
Published: September 2003

Disabled‐1 (Dab1) is an adapter molecule in a signaling pathway, stimulated by reelin, that controls cell positioning in the developing brain. It localizes to selected neurons in the nervous system, including the retina, and Dab1‐like immunoreactivity is present in AII amacrine cells in the mouse retina. This study was conducted to characterize Dab1‐labeled cells in the guinea pig retina in detail using immunocytochemistry, quantitative analysis, and electron microscopy. Dab1 immunoreactivity is present in a class of amacrine cell bodies located in the inner nuclear layer adjacent to the inner plexiform layer (IPL). These cells give rise to processes that ramify the entire depth of the IPL. Double‐labeling experiments demonstrated that these amacrine cells make contacts with the axon terminals of rod bipolar cells and that their processes make contacts with each other via connexin 36 in sublamina b of the IPL. In addition, all Dab1‐labeled amacrine cells showed glycine transporter 1 immunoreactivity, indicating that they are glycinergic. The density of Dab1‐labeled AII amacrine cells decreased from about 3,750 cells/mm2 in the central retina to 1,725 cells/mm2 in the peripheral retina. Dab1‐labeled amacrine cells receive synaptic inputs from the axon terminals of rod bipolar cells in stratum 5 of the IPL. From these morphological features, Dab1‐labeled cells of the guinea pig retina resemble the AII amacrine cells described in other mammalian species. Thus, the rod pathway of the guinea pig retina follows the general mammalian scheme and Dab1 antisera can be used to identify AII amacrine cells in the mammalian retina. J. Comp. Neurol. 466:240–250, 2003. © 2003 Wiley‐Liss, Inc.
Intercellular interactions in the mammalian olfactory nerve
Authors: Blinder Karen J. , Pumplin David W. , Paul D.L. , Keller Asaf
Published: September 2003

The small, unmyelinated axons of olfactory sensory neurons project to the olfactory bulb in densely packed fascicles, an arrangement conducive to axo‐axonal interactions. We recently demonstrated ephaptic interactions between these axons in the olfactory nerve layer, the layer of the olfactory bulb in which the axon fascicles interweave and rearrange extensively. In the present study, we hypothesized that the axons, which express connexins, may have another mode of communication: gap junctions. Previous transmission electron microscopy (TEM) studies have failed to demonstrate such junctions. However, the definitive method for detecting gap junctions, freeze fracture, has not been used to examine the interaxonal connections of the olfactory nerve layer. Here, we apply a combined approach of TEM and freeze fracture to determine if gap junctions are present between the olfactory axons. Gap junctions involving olfactory axons were not found. However, by freeze fracture, P faces of both the axons and ensheathing cells (glia that surround the axon fascicles) contained distinctive linear arrays of particles, aligned along the small columns of extracellular space. In axons, few intramembranous particles were present outside of these arrays. Multi‐helix proteins, including ion channels and connexin hemichannels, have been shown to be visible as particles by freeze fracture. This suggests that the proteins important for signal transmission are confined to the linear arrays. Such an arrangement would facilitate ephaptic transmission, calcium waves, current oscillations, and paracrine communication and may be important for olfactory neural code processing. J. Comp. Neurol. 466:230–239, 2003. © 2003 Wiley‐Liss, Inc.
Collateralization of climbing and mossy fibers projecting to the nodulus and flocculus of the rat cerebellum
Authors: Ruigrok Tom J.H.
Published: September 2003

Collateralization of mossy and climbing fibers was investigated using cortical injections of cholera toxin b‐subunit in the rat vestibulocerebellum. Injections were characterized by their retrograde labeling within the inferior olive. Collateral labeling was plotted using color‐coded density profiles of the whole cerebellar cortex. Injections in the medial part of the nodulus resulted in olivary labeling that was restricted to the rostral part of the dorsal cap. Climbing fiber collaterals were found in medial and lateral nodular zones as well as in the ventral paraflocculus and adjacent flocculus. Injections in the intermediate part of the nodulus resulted in olivary labeling of the β‐subnucleus but could also involve the ventrolateral outgrowth. In the latter case, climbing fiber collaterals were found in the two floccular zones and in a small region in the lateral‐most part of crus I. All nodular injections showed a bilaterally symmetric distribution of collateral mossy fiber rosettes that was mostly confined to the vestibulocerebellum and originated predominantly from the vestibular nuclei. Injections in the flocculus labeled the caudal part of the dorsal cap and/or the ventrolateral outgrowth. Mossy fiber rosettes were observed throughout the vestibulocerebellum but also included other regions of the cerebellar cortex in a bilaterally symmetric pattern corresponding with a more widespread precerebellar origin. Climbing fibers originating in the rostral dorsal cap, labeled from an injection in the ventral paraflocculus, collateralize to a medial and lateral zone in the nodulus. Climbing fiber collaterals were usually accompanied by subjacent labeling of mossy fiber rosettes. These results demonstrate that some nodular and floccular zones are related and, at least partially, share a common input. J. Comp. Neurol. 466:278–298, 2003. © 2003 Wiley‐Liss, Inc.
Topological degree for a mean field equation on Riemann surfaces
Authors: Chen Chiun‐Chuan , Lin Chang‐Shou
Published: September 2003

We consider the following mean field equations:

where M is a compact Riemann surface with volume 1, h is a positive continuous function on M, ρ is a real number,

and where Ω is a bounded smooth domain, h is a C1 positive function on Ω, and ρ ∈ ℝ. Based on our previous analytic work [14], we prove, among other things, that the degree‐counting formula for (0.1) is given by () for ρ ∈ (8mπ, 8(m + 1)π). © 2003 Wiley Periodicals, Inc.
Nontopological N‐vortex condensates for the self‐dual Chern‐Simons theory
Authors: Nolasco Margherita
Published: September 2003

We prove the existence of nontopological N‐vortex solutions for an arbitrary number N of vortex points for the self‐dual Chern‐Simons‐Higgs theory with 't Hooft “periodic” boundary conditions. We use a shadowing‐type lemma to glue together any number of single vortices obtained as a perturbation of a radially symmetric entire solution of the Liouville equation. © 2003 Wiley Periodicals, Inc.
Sub‐optimal control of structures
Authors: Cai Guo‐Ping , Sun Feng
Published: September 2003

It is well known that the classical optimal control method requires all the state variables of the controlled system to be measurable and available for control feedback. However, for a high‐order or complex system some state variables are possibly unmeasurable in practice. In addition, the control cost will be higher if more sensors are used, because it is expensive to install sensors. On the other hand, when using the optimal control method with full‐state feedback, some state variables in control feedback have only a small effect on control performance. Neglecting these state variables does not affect the control performance greatly. Good control effectiveness can be obtained by using only the state variables that have a big effect on the control performance. So the questions become how to determine those state variables which have a big effect on the control performance? and how to design the optimal controller using only the determined state variables?

The discrete sub‐optimal control method with partial‐state feedback is investigated in this paper. Firstly, the continuous control system and performance index are both transformed into discrete forms. Then the state variables, which have a big effect on the control performance, are determined using the second‐order sensitivity which is the second‐order derivative of the performance index with respect to control gain. The sub‐optimal controller is finally designed using only the determined state variables. Numerical examples are worked out to demonstrate the application of the proposed control algorithm. It is shown that the relative importance of each state variable can be indicated clearly by the second‐order sensitivity. The sub‐optimal control method presented is effective in reducing maximum responses of the structure. Copyright © 2003 John Wiley & Sons, Ltd.