bluuebunny/crossref_metadata_2025_split huggingface dataset:
Culture of primary rat hepatocytes within porous chitosan scaffolds
Authors: Li Jieliang , Pan Jilun , Zhang Liguo , Guo Xinji , Yu Yaoting 
Published: November 2003

AbstractChitosan is considered to be a very promising biopolymer for various biomedical and pharmaceutical uses because of its nontoxic and biocompatible natures (Chandy T, Shama P. Biomater Artif Cells Artif Org 1990;18:1–24). In this study, we prepared porous chitosan scaffolds by lyophilization of chitosan solution. The scaffolds were modified with water‐soluble polyanionic species such as alginate and heparin. The pore structures of these scaffolds were viewed via light and scanning electron microscopy. The scaffolds prepared have a high porosity of ∼90% with mean pore sizes from 50 to 200 μm. They were used as substrates for hepatocytes culture. The cell attachment ratio was much higher than on monolayer membrane and hepatocytes exhibited a round cellular morphology with many microvilli evident on the surface of the cells. Metabolic activities of the cells were evaluated in terms of albumin secretion and urea synthesis. It was found that hepatocytes cultured on the modified scaffolds showed an increase in albumin secretion during the first 4 days and were more stable than those on monolayer membrane and nonmodified scaffolds. Therefore, primary rat hepatocytes cultured on modified scaffolds would be beneficial to liver assist device. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 938–943, 2003
Public–private community partnerships in infrastructure for the poor
Authors: Franceys Richard , Weitz Almud 
Published: November 2003

AbstractThere is an urgent need to improve the delivery of water and environmental sanitation services to the urban poor in low and middle‐income countries to protect health and to promote sustainable livelihoods. Conventional support to public providers through loans for capital investment linked to capacity building has not achieved the desired results. There is a growing awareness of the need for institutional reform to overcome the all too common failures if service to the poor is to reach an acceptable level.The urban poor in Asia typically represent one quarter to one half of a fast growing urban area's population often dwelling in unplanned areas without any security of tenure. A study was undertaken in ten Asian countries to investigate the roles of and interaction between the public sector, private entities and civil society in serving the urban poor with water supply, sanitation and solid waste management. Case studies, including focus group discussions with low‐income slum residents, were undertaken by country‐based researchers distributed over a spectrum of service type, country population, city size and institutional/contract type to investigate the benefits of infrastructure partnerships.Analysis of the 20 studies confirmed the limited ability of existing public entities to reach the poor. The essential need for some level of service provision was being met by a mixture of poor quality self‐provision, by informal private entities often at high, unregulated prices, or by innovative civil society involvement experiencing difficulties in scaling‐up. A number of the new public private approaches were found to be successfully reforming the direct public providers; however these were usually serving poor people only by default through the general improvement in performance. A very limited number of public private community partnerships with international operators were found to be dramatically improving service to some of the poor, with better quality at lower price, but often with long‐term uncertainty over contractual stability. Copyright © 2003 John Wiley & Sons, Ltd.
A theoretical explanation for the retention mechanism of ion exclusion chromatography
Authors: Głód Bronisław K. , Baumann Marc 
Published: November 2003

AbstractIon Exclusion Chromatography is classically used for the separation of weak acid anions. Dilute strong acids (e.g. sulphuric or perchloric acid) or just water are used as eluents. To increase the exclusion effect, strong cation exchangers, characterized by high concentration of functional groups, are applied. The inner column volume of commercially available columns is increased by increasing their size in comparison to traditional ones (usually 300×7.8 mm ID). The description of the retention mechanism of this technique implicitly assumes that both mobile and stationary phases are typical aqueous solutions, and their dielectric constants are thus equal. This equality implies the equality of solute dissociation constants in both phases. Another implicit assumption is that the dead‐ and inner volumes of the column are constant, and independent of the mobile phase composition. The present paper shows that stationary and mobile phases are generally characterized by different physicochemical parameters. Thus, they cannot be considered as regular aqueous solutions. Additionally, we show that weak cation exchanger resins, which are characterized by a relatively small concentration of the functional groups, and weak acid based buffers can also be used in IEC. This would expand the possible applications of this method and enable, for example, the separation of strong acids (anions). The influence of ionic strength on the retention and dead‐ and inner column volumes is also discussed. Finally we also briefly describe the retention mechanism of Electrostatic Ion Chromatography.
Ultra‐rapid non‐equilibrium solid‐phase microextraction at elevated temperatures and direct coupling to mass spectrometry for the analysis of lidocaine in urine
Authors: van Hout Mischa W. J. , Jas Vincent , Niederländer Harm A. G. , de Zeeuw Rokus A. , de Jong Gerhardus J. 
Published: November 2003

AbstractSolid‐phase microextraction (SPME) has been directly coupled to an ion‐trap mass spectrometer (MS) for the determination of the model compound lidocaine in urine, hereby applying MS/MS [fragmentation of [M + H]+ (m/z 235) to a fragment with m/z 86]. The throughput of samples has been increased using non‐equilibrium SPME with polydimethylsiloxane (PDMS) fibers. The effect of temperature on the sorption and the desorption was studied. Elevated temperatures during sorption (65°C) and desorption (55°C) had a considerable influence on the speed of the extraction. The desorption was carried out with a home‐made desorption chamber allowing thermostating. Only 1 min sorption and 1 min desorption were performed, after which MS detection took place, resulting in a total analysis time of 3 min. Detection limits below 1 ng/mL could be obtained despite yields of only 2.1 and 1.5% for a 100‐ and a 30‐μm PDMS‐coated fiber, respectively. Furthermore, the determination of lidocaine in urine had acceptable reproducibilities, i.e., relative standard deviations (RSDs) below 10%. A limit of quantitation (RSD < 15%) of about 1 ng/mL was obtained. No extra wash step of the extraction fiber was required after desorption if a 30‐μm coating was used, whereas not all the analyte was desorbed from the 100‐μm coating in a single desorption. Therefore, the SPME‐MS/MS system with a 30‐μm PDMS‐coated fiber for rapid non‐equilibrium SPME at elevated temperatures has interesting potential for high‐throughput analysis of biological samples.
A comparative study of hospitality and tourism graduates in Australia and Hong Kong
Authors: King Brian , McKercher Bob , Waryszak Robert 
Published: November 2003

AbstractThis paper evaluates the career experiences and perceptions of graduates from the School of Hotel and Tourism Management at the Hong Kong Polytechnic University and the School of Hospitality, Tourism and Marketing at Victoria University in Melbourne, Australia towards the programmes that they undertook. The two cohorts of graduates exhibited broadly similar career histories and expressed similar attitudes towards the quality, strengths and weaknesses of their respective programmes. In both cases, female students dominate the graduate cohort and about half of the respondents were found to have left the tourism or hospitality field within 3–5 years after graduation. Graduates believe that their general business and general education subjects play a stronger role in acquiring their first and current jobs than specialist tourism, hotel management and food service subjects. The findings highlight the challenge facing the university sector in attempting to balance the desire to provide a broadly grounded liberal education with the student desire for practical training. Copyright © 2003 John Wiley & Sons, Ltd.
In the air again: frequent flyer relationship programmes and business travellers' quality of life
Authors: Long Mary M. , Clark Sylvia D. , Schiffman Leon G. , McMellon Charles 
Published: November 2003

AbstractThis research explores whether frequent flyer programmes somehow add to the quality of life of the frequent business traveller (defined in this study as business flyers who had flown round trip 26 or more times in the past 12 months). A questionnaire was mailed to subscribers of a newsletter for members of frequent air and hotel programmes. Results indicated that frequent flyer programmes contribute positively to frequent business travellers' lifestyles and to their quality of life, perhaps by countervailing some of the negative aspects of frequent business travel. Copyright © 2003 John Wiley & Sons, Ltd.
Economic aspects and the Summer Olympics: a review of related research
Authors: Kasimati Evangelia 
Published: November 2003

AbstractAs the Summer Olympics are growing with larger media coverage and sponsorship, host cities have started to attach great importance to the tourism and other likely economic effects that occur by staging such a special event. As a result, a number of studies have been conducted to consider the various economic implications on the hosts. This paper examines and evaluates methods and assumptions used by the economic studies. It also comparesex‐antemodels and forecasts with theex‐postapproach. The aim is to improve the information available to policy makers and potential future hosts of Summer Olympics and other mega‐events. Copyright © 2003 John Wiley & Sons, Ltd.
Domestic tourism destination choices — a choice modelling analysis
Authors: Huybers Twan 
Published: November 2003

AbstractTourism destinations compete with each other to attract visitors. Although international tourism has received a lot of attention, domestic tourism remains the mainstay for many destinations. To inform the basis on which destinations compete, an understanding of the determinants of destination choices is required. In this paper, the discrete choice modelling method is applied to investigate the determining factors underlying the short‐break holiday destination choices of prospective tourists from Melbourne, Australia. The results from an estimated nested logit model indicate the relative importance of a number of destination and trip attributes and respondent characteristics. The model results are used to simulate the effects on destinations' market shares resulting from various changes in attributes and tourist characteristics. Copyright © 2003 John Wiley & Sons, Ltd.
Novel Semi‐Fluorinated Poly(ether imide)s Derived From 4‐(p‐Aminophenoxy)‐3‐trifluoromethyl‐4′‐aminobiphenyl
Authors: Kute Vijay , Banerjee Susanta 
Published: November 2003

AbstractAn unsymmetrical diamine monomer 4‐(p‐aminophenoxy)‐3‐trifluoromethyl‐4′‐aminobiphenyl has been synthesized successfully. This monomer leads to the synthesis of different novel poly(ether imide)s when reacted with different dianhydrides like pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA), 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane (6FDA), and oxy diphthalic anhydride (ODA). The poly(ether imide) prepared from this monomer on reaction with 6FDA is soluble in several organic solvents such as N‐methylpyrolidinone (NMP), dimethylformamide (DMF), N,N‐dimethylacetamide (DMAc), tetrahydrofuran (THF), and CHCl3. The poly(ether imide)s prepared from BTDA and ODA are soluble in NMP, DMF, and DMAc but not in THF or CHCl3, whereas the polymer prepared from PMDA is soluble only in NMP. The water uptake value for these poly(ether imide) films is very low (0.2–0.5%), and exhibited low dielectric constants (2.81 at 1 MHz). The polymers exhibited high thermal stability up to 532 °C in air for 5% weight loss, and high glass transition temperatures up to 288 °C. The polymer exhibited high tensile strength up to 135 MPa, modulus 3.2 GPa, and elongation at break up to 25%, depending on the exact polymer structure.The structure of the poly(ether imide) synthesised from 4‐(p‐aminophenoxy)‐3‐trifluoromethyl‐4′‐aminobiphenyl and 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane. This polymer was soluble in many organic solvents.magnified imageThe structure of the poly(ether imide) synthesised from 4‐(p‐aminophenoxy)‐3‐trifluoromethyl‐4′‐aminobiphenyl and 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane. This polymer was soluble in many organic solvents.
Novel Superlattices via Blending of Asymmetric Triblock Terpolymers with Diblock Copolymers
Authors: Jiang Shimei , Göpfert Astrid , Abetz Volker 
Published: November 2003

AbstractThe formation of superlattices in blends of a series of asymmetric BSV triblock terpolymers and symmetric SV or VC diblock copolymers is investigated with S being polystyrene, B being poly(1,2‐butadiene), V being poly(2‐vinylpyridine), and C being poly(cyclohexyl methacrylate). All of these triblock terpolymers and diblock copolymers by themselves self‐assemble into lamellae. Apart from various core shell morphologies, in these blends some new unexpected superstructures were obtained.A TEM micrograph of a 50/50 blend of B30S58V with S45V.magnified imageA TEM micrograph of a 50/50 blend of B30S58V with S45V.
Influence of particle shape and angularity on the behaviour of granular materials: a numerical analysis
Authors: Nouguier‐Lehon C. , Cambou B. , Vincens E. 
Published: November 2003

AbstractThis paper analyses the influence of grain shape and angularity on the behaviour of granular materials from a two‐dimensional analysis by means of a discrete element method (Contact Dynamics). Different shapes of grains have been studied (circular, isotropic polygonal and elongated polygonal shapes) as well as different initial states (density) and directions of loading with respect to the initial fabric. Simulations of biaxial tests clearly show that the behaviour of samples with isotropic particles can be dissociated from that of samples with anisotropic particles. Indeed, for isotropic particles, angularity just tends to strengthen the behaviour of samples and slow down either local or global phenomena. One of the main results concerns the existence of a critical state for isotropic grains characterized by an angle of friction at the critical state, a critical void ratio and also a critical anisotropy. This critical state seems meaningless for elongated grains and the behaviour of samples generated with such particles is highly dependent on the direction of loading with respect to the initial fabric. The study of local variables related to fabric and particle orientation gives more information. In particular, the coincidence of the principal axes of the fabric tensor with those of the stress tensor is sudden for isotropic particles. On the contrary, this process is gradually initiated for elongated particles. Copyright © 2003 John Wiley & Sons, Ltd.
Micro‐mechanical simulation of geotechnical problems using massively parallel computers
Authors: Washington David W. , Meegoda Jay N. 
Published: November 2003

AbstractThis paper demonstrates that the architecture of a massively parallel computer can be adapted for micro‐mechanical simulations of a Geotechnical problem. The Discrete Element Method was used on a massively parallel supercomputer to simulate Geotechnical boundary value problems. For the demonstration, a triaxial test was simulated using an algorithm titled ‘TRUBAL for Parallel Machines (TPM)’ based on the discrete element method (DEM). In this trial demonstration, the inherent parallelism within DEM algorithm is shown. Then a comparison is made between the parallel algorithm (TPM) and the serial algorithm (TRUBAL) to show the benefits of this research. TPM showed substantial improvement in performance with increasing number of processors when compared with TRUBAL using single processor. Copyright © 2003 John Wiley & Sons, Ltd.
Age‐related differences in synaptic plasticity following muscle unloading
Authors: Deschenes Michael R. , Wilson Meredith H. 
Published: November 2003

AbstractThe objective of the present investigation was to determine the effects of muscle unloading—a form of subtotal disuse— on the morphology of the neuromuscular junction (NMJ) in younger and aged animals. Sixteen aged (22 months) and 16 young adult (8 months) male Fischer 344 rats were assigned to control and hindlimb suspension (HS) conditions (n = 8/group). At the conclusion of the 4 week experimental period, soleus muscles were collected, and immunofluorescent procedures were used to visualize acetylcholine (ACh) vesicles and receptors, nerve terminal branching, as well as NCAM and NT‐4 expression. Quantitative analyses revealed that aged controls displayed significant (p < 0.05) reductions in area and perimeter length of ACh vesicle and receptor regions, without affecting nerve terminal branch number or length. In contrast to younger NMJs, which were resilient to the effects of unloading, NMJs of aged HS rats demonstrated significant expansion of ACh vesicle and receptor dimensions compared to aged controls. Qualitative analyses of NCAM staining indicated that aging alone somewhat increased this molecule's expression (aged controls > young controls). Among the four groups, however, the greatest amount of NCAM content was detected among aged HS muscles, matching the degree of synaptic plasticity exhibited in those muscles. Unlike NCAM, the expression of NT‐4 did not appear to differ among the treatment groups. These data suggest that although young adult muscle maintains normal NMJ structure during prolonged exposure to unloading, aged NMJs experience significant adaptation to that stimulus. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 246–256, 2003
Newly proliferated cells in the adult male amygdala are affected by gonadal steroid hormones
Authors: Fowler Christie D. , Freeman Marc E. , Wang Zuoxin 
Published: November 2003

AbstractGonadal steroid hormones play an important role in the proliferation, survival, and activation of neurons. The present study was performed to examine the effects of testosterone and its metabolites on newly proliferated cells in the amygdala of adult male meadow voles (Microtus pennsylvanicus). Treatment with testosterone propionate (TP) in castrated males resulted in plasma testosterone levels similar to males following mating. TP‐treated males displayed a significant increase in the density of cells labeled with a cell proliferation marker (BrdU) in the amygdala. Treatment with estradiol benzoate (EB) exerted a similar effect as TP on the density of BrdU‐labeled cells, whereas 5α‐dihydrotestosterone (DHT) was ineffective. A larger proportion (≈44%) of the BrdU‐labeled cells in the amygdala displayed a neuronal phenotype, and a lesser percentage (≈35%) displayed a glial progenitor phenotype; however, treatment effects were not found in either population of cells. Hormonal effects appeared to be site‐specific as no group differences were found in the dentate gyrus of the hippocampus or ventromedial hypothalamus. Finally, a time course study indicated that BrdU‐labeled cells in the amygdala are present as early as 30 min following an acute injection of BrdU. Together, these data suggest that gonadal steroid hormones influence the number of newly proliferated cells in the amygdala, most likely by acting through an estrogenic mechanism, and these effects may be exerted on locally proliferating progenitors within the amygdala. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 257–269, 2003
Gain‐of‐function screen identifies a role of the Src64 oncogene in Drosophila mushroom body development
Authors: Nicolaï Maryse , Lasbleiz Christelle , Dura Jean‐Maurice 
Published: November 2003

AbstractMushroom bodies (MB) are substructures in the Drosophila brain that are essential for memory. At present, MB anatomy is rather well described when compared to other brain areas, and elucidation of the genetic control of the development and projection patterns of MB neurons will be important to the understanding of their functions. We have performed a gain‐of‐function screen in order to identify genes that are involved in MB development. We drove expression of genes in MB neurons by crossing 2407 GAL4‐driven UY element lines to lines containing an MB GAL4 source and UAS‐GFP elements, and looked for defects in the MB structure. We have molecularly identified the genomic regions adjacent to the 26 positive UY insertions and found 18 potential genes that exhibit adult MB gain‐of‐function phenotypes. The proteins encoded by these candidate genes include, as well as genes with yet unknown function, transcription factors (e.g., tramtrack), nanos RNA‐binding protein, microtubule‐severing protein, vesicle trafficking proteins, axon guidance receptor, and the Src64 cytoplasmic protein tyrosine kinase. These genes are involved in key features of neuron cell biology. In three cases, tramtrack, nanos, and Src64, we show that the open reading frame located directly downstream of the UY P element is indeed the expressed target gene. Loss‐of‐function mutations of both ttk and Src64 lead to MB phenotypes proving that these genes are involved in the genetic control of MB development. Moreover, Src64 is shown here to act in a cell‐autonomous fashion and is likely to interact with the previously‐identified linotte/derailed receptor tyrosine kinase in MB development. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 291–302, 2003
Excess FoxG1 causes overgrowth of the neural tube
Authors: Ahlgren Sara , Vogt Peter , Bronner‐Fraser Marianne 
Published: November 2003

AbstractThe winged helix transcription factor FoxG1 (Bf‐1, qin) plays multiple roles in the development of the telencephalon, with different parts of the protein affecting either proliferation or differentiation. We examined the consequences of over‐expression, via retroviral expression, of FoxG1 on the growth of different regions of the chicken brain. Excess expression of FoxG1 caused a thickening of the neuroepithelium, and ultimately large outgrowths of the telencephalon and mesencephalon. In contrast, the myelencephalon appeared unaffected, exhibiting normal apoptosis and growth characteristics. A DNA binding defective form of FoxG1 did not exhibit these abnormalities, suggesting that these effects are due to FoxG1's function as a transcriptional repressor. To examine the means by which excess FoxG1caused overgrowth of the brain, we examined alterations in cell proliferation and death. No increase in proliferation was noted in any portion of the neural tube, rather a significant decrease in neuroepithelial apoptosis was seen. These results demonstrate a previously unrecognized role for winged helix factors in the regulation of neural cell apoptosis. © 2003 Wiley Periodicals, Inc. J Neurobiol 57: 337–349, 2003