bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blending polysaccharides with biodegradable polymers. II. Structure and biological response of chitosan/polycaprolactone blends
Authors: García Cruz Dunia M. , Coutinho Daniela F. , Costa Martinez Elisa , Mano João F. , Gómez Ribelles José Luis , Salmerón Sánchez Manuel 
Published: June 2008

AbstractBlends of polycaprolactone (PCL) and chitosan (CHT) were prepared by casting from the mixture of solutions of both components in suitable solvents. PCL, and CHT, form phase separated blends with improved mechanical properties and increased water sorption ability with respect to pure PCL. The morphology of the system was investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and confocal microscopy. Dispersed domains of CHT in the semicrystalline PCL matrix were found in samples with less than 20% CHT but cocontinuous phase morphologies are found in blends with 20% or more CHT. This feature was corroborated by the temperature dependence of the elastic modulus measured by dynamic mechanical properties as a function of temperature. It was observed that for those blends above 20 wt% CHT, the mechanical stability of the system was kept even after melting of the PCL phase. Primary human chondrocytes were cultured on the different substrates. Cell morphology was studied by SEM and the viability and proliferation was investigated by the colorimetric MTT assay. Different protein conformations were found by AFM on CHT and PCL samples which were related to the biological performance of the substrates. Hydrophilicty of the material is not directly related to the biological response and the sample with 20 wt% CHT shows better results than the other blends with respect to chondrocyte viability and proliferation. However, the results obtained in the blends are worse than in pure PCL. It seems to be correlated with the surface energy of the different blends rather than hydrophilicity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Corrosion of dental nickel–aluminum bronze with a minor gold content‐mechanism and biological impact
Authors: Ardlin Berit I. , Lindholm‐Sethson Britta , Dahl Jon E. 
Published: June 2008

AbstractObjectives: To study corrosion and to evaluate biological effects in vitro of corrosion products of a copper‐aluminum‐nickel alloy with 2% gold. Methods: The alloy NPG™+2 with the nominal composition Cu:77.3; Al:7.8; Ni:4.3; Fe:3.0; Zn:2.7; Au:2.0; and Mn:1.7 was characterized. Static immersion in acidic saline, pH 2.2–2.4, was used to determine release of metallic elements in a milieu simulating the condition of plaque build‐up in interproximal areas of the tooth. Corrosion and surface reactions in saline and artificial saliva were studied by electrochemical techniques including registration of open‐circuit‐potentials, polarization curves and impedance spectra. Extracts were made in cell culture media and acidic saline and used for MTT test for cytotoxicity and HET‐CAM method for irritation. Results: The mean amount of elements released in the acidic saline were in μg cm−2 : Cu:632; Al:210; Ni:144; Fe:122; Zn:48; Mn:52. No protective film was formed on the surface of the alloy, as extensive corrosion was observed in both saline and artificial saliva. The corrosion rate was higher in saline than in artificial saliva. Acidic extracts of the alloy diluted up to 64 times reduced cell viability with 80% or more. The extract induced coagulation of the blood vessels of the CAM and was rated as moderate irritant solution. Significance: The nickel–aluminum bronze showed high corrosion rate caused by an inability to create a protective surface layer. High levels of toxic elements were found after static immersion testing, and the corrosion products had a distinct adverse effect on the biological activity. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Customizing the degradation and load‐bearing profile of 3D polycaprolactone‐tricalcium phosphate scaffolds under enzymatic and hydrolytic conditions
Authors: Yeo Alvin , Sju Ervi , Rai Bina , Teoh Swee Hin 
Published: June 2008

AbstractThe degradation of polycaprolactone‐20% tricalcium phosphate (PCL‐TCP) scaffolds was customized for dentoalveolar augmentation applications, where 5–6 months period is optimal. The scaffolds were treated with either 3M sodium hydroxide (NaOH) or 0.1% lipase solution for a total of 108 h. A greater degree of degradation and reduction in the physical properties of the scaffolds was observed in the lipase treated when compared with NaOH‐treated scaffolds. After 108 h, increases in weight loss and average porosity of the scaffolds in the lipase‐treated group measured 90.6% and 22.9%, respectively, when compared with 52.8% and 11.8% in the NaOH‐treated group. The mechanical testing results revealed a similar trend, with a complete loss of compressive strength and modulus measured as early as 60 h in the lipase‐treated group. The honeycomblike architecture was well preserved throughout the experiment only for the NaOH‐treated scaffolds in addition to a favorable surface roughness ideal for bone‐regeneration applications. In conclusion, pretreatment with NaOH demonstrates a simple approach for tailoring the physical properties and degradation rate of PCL‐TCP scaffolds for the potential use as biomaterials targeted for dentoalveolar bone‐regeneration procedures. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Effect of 3D‐microstructure of bioabsorbable PGA:TMC scaffolds on the growth of chondrogenic cells
Authors: Mukherjee Debi P. , Smith Dollie F. , Rogers Shelia H. , Emmanual Janson E. , Jadin Kyle D. , Hayes Byron K. 
Published: June 2008

AbstractVarious biomaterial scaffolds have been investigated for cartilage tissue engineering, although little attention has been paid to the effect of scaffold microstructure on tissue growth. Non‐woven, fibrous, bioabsorbable scaffolds constructed from a copolymer of glycolide and trimethylene carbonate with varying levels of porosity and pore size were seeded with mesenchymal stroma cells with a chondrogenic lineage. Scaffolds and media were evaluated for both cell and extracellular matrix organization and content after up to 28 days of culture in a spinner flask. Analysis of DNA and glycosaminoglycan contents showed that the most porous of the three scaffold types, with a porosity of 81% and a porometry determined mean flow pore diameter of 54 μm, supported the most rapid proliferation of cells and accumulation of extracellular matrix. Analysis of the high porosity scaffold system, using Western Blot and immunohistochemistry confirmed the presence of collagen type II and absence of collagen type I, and demonstrated cells with a chondrocyte morphology with aggrecan and collagen II accumulation attached to the scaffolds. It was concluded that the 3D‐microstructural characteristics of the scaffold (interconnecting porosity and pore size) play an important role in proliferation and phenotype of chondrogenic cells and accumulation of extracellular matrix molecules. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Internalization and degradation of heparin is not required for stimulus of heparan sulfate proteoglycan synthesis
Authors: Trindade Edvaldo S. , Bouças Rodrigo I. , Rocha Hugo A.O. , Dominato Juliana A. , Paredes‐Gamero Edgar J. , Franco Célia Regina C. , Oliver Constance , Jamur Maria C. , Dietrich Carl P. , Nader Helena B. 
Published: June 2008

AbstractIn vitro, heparin and antithrombotic drugs specifically stimulate the synthesis of an antithrombotic heparan sulfate proteoglycan (HSPG) produced by endothelial cells. The putative heparin binding site(s) that may be related to this phenomenon were investigated. In the preceding article, using various heparin probes, it was shown that the heparin does not bind to the endothelial cell surface, but only to the extracellular matrix. The present study demonstrated that, when the cells were exposed to heparin at 37°C, the heparin was internalized and with time was localized in lysosomes. However, endocytosis of heparin was not required for the stimulation of HSPG synthesis. The requirement for heparin degradation in the stimulus of HSPG synthesis was also investigated. When the cells were incubated with chloroquine, a lysosomotropic amine that raises the lysosomal pH thus inhibiting enzymatic degradation of internalized compounds, stimulation of HSPG synthesis was still observed. These combined results indicate that neither internalization nor degradation of heparin is required for stimulation of HSPG synthesis, and suggests that its binding to the extracellular matrix could be responsible for this effect. J. Cell. Physiol. 217: 360–366, 2008. © 2008 Wiley‐Liss, Inc.
Protein purification using chromatography: selection of type, modelling and optimization of operating conditions
Authors: Asenjo J. A. , Andrews B. A. 
Published: June 2008

AbstractTo achieve a high level of purity in the purification of recombinant proteins for therapeutic or analytical application, it is necessary to use several chromatographic steps. There is a range of techniques available including anion and cation exchange, which can be carried out at different pHs, hydrophobic interaction chromatography, gel filtration and affinity chromatography. In the case of a complex mixture of partially unknown proteins or a clarified cell extract, there are many different routes one can take in order to choose the minimum and most efficient number of purification steps to achieve a desired level of purity (e.g. 98%, 99.5% or 99.9%).This review shows how an initial 'proteomic' characterization of the complex mixture of target protein and protein contaminants can be used to select the most efficient chromatographic separation steps in order to achieve a specific level of purity with a minimum number of steps. The chosen methodology was implemented in a computer‐ based Expert System. Two algorithms were developed, the first algorithm was used to select the most efficient purification method to separate a protein from its contaminants based on the physicochemical properties of the protein product and the protein contaminants and the second algorithm was used to predict the number and concentration of contaminants after each separation as well as protein product purity.The application of the Expert System approach was experimentally tested and validated with a mixture of four proteins and the experimental validation was also carried out with a supernatant of Bacillus subtilis producing a recombinant β‐1,3‐glucanase.Once the type of chromatography is chosen, optimization of the operating conditions is essential. Chromatographic elution curves for a three‐protein mixture (α‐lactoalbumin, ovalbumin and β‐lactoglobulin), carried out under different flow rates and ionic strength conditions, were simulated using two different mathematical models. These models were the Plate Model and the more fundamentally based Rate Model. Simulated elution curves were compared with experimental data not used for parameter identification. Deviation between experimental data and the simulated curves using the Plate Model was less than 0.0189 (absorbance units); a slightly higher deviation [0.0252 (absorbance units)] was obtained when the Rate Model was used. In order to optimize operating conditions, a cost function was built that included the effect of the different production stages, namely fermentation, purification and concentration. This cost function was also successfully used for the determination of the fraction of product to be collected (peak cutting) in chromatography. It can be used for protein products with different characteristics and qualities, such as purity and yield, by choosing the appropriate parameters. Copyright © 2008 John Wiley & Sons, Ltd.
Changes of the composition in acerola (Malpighia emarginata DC.) fruit in relation to cultivar, growing region and maturity
Authors: Hanamura Takayuki , Uchida Eriko , Aoki Hitoshi 
Published: June 2008

AbstractBACKGROUND: Acerola (Malpighia emarginata DC.) has been known as a fruit rich in vitamin C. However, changes in composition of constituents in relation to cultivar, growing region and maturity have not been studied. We investigated the composition for five types of acerola fruits: three different cultivars (‘BOK’, ‘Flor Branca’ and ‘NRA309’) growing in Brazil, and one cultivar each in Vietnam (‘Vietnam’) and in Japan (‘Okinawa’). We also investigated the influence of fruit maturity on the compositional profiles.RESULTS: ‘BOK’ showed the highest vitamin C and malic acid contents whereas ‘Vietnam’ had the lowest vitamin C content. On the other hand, ‘NRA 309’ showed the highest level of total polyphenols. In the study of compositional changes during maturation, it was found that at immature stages proanthocyanidin was the major flavonoid, with high vitamin C content, but the levels of these constituents decreased as ripening progressed. At mature stages, anthocyanins appeared to be the major polyphenol in the ripe acerola fruit.CONCLUSION: This study showed that composition of acerola fruit differed significantly according to cultivar, growing region and maturity. The information provided in this study may help consumers to make an appropriate selection of functional food. Copyright © 2008 Society of Chemical Industry
Alternating Copolymer of Sulfonated Poly(ether ether ketone‐benzimidazole)s (SPEEK‐BI) Bearing Acid and Base Moieties
Authors: Wang Jianli , Song Yilin , Zhang Cheng , Ye Zhibin , Liu Hui , Lee Myong‐Hoon , Wang Dehai , Ji Jianbing 
Published: June 2008

AbstractA novel alternating copolymer of sulfonated poly(ether ether ketone‐benzimidazole)s (SPEEK‐BI) was synthesized by polycondensation of aromatic bisphenol containing benzimidazole and a mixture of sulfonated and non‐sulfonated difluorobenzophenones. By varying the amount of two difluorobenzophenones, the ratio of sulfonic acid unit to imidazole base was controlled straightforwardly. The polymer structure was characterized by 1H NMR and IR spectroscopy. Two different methods of ion exchange capacity measurement supported a strong inter‐ and intra‐molecular interaction between acid and base units, which resulted in an improved mechanical strength as well as avoiding phase separation. Tough membranes with good mechanical stability in hot water (80 °C) and alcohol were obtained by solution casting, which is potential for applications in polymer electrolyte membrane fuel cells and membranes for separation of liquids or gases.magnified image
Consumer acceptance of online auctions: An extension and revision of the TAM
Authors: Stern Barbara B. , Royne Marla B. , Stafford Thomas F. , Bienstock Carol C. 
Published: June 2008

AbstractThe study extends and revises the original Technology Acceptance Model (TAM) by applying it in the context of online auctions and introducing three new consumer‐oriented variables: affinity with the computer, impulsiveness, and risk tolerance. It begins with an examination of eBay, the first and most successful online auction site, to show that its business is the technology that fuels growth and increased profits. The paper then addresses the original cognitive TAM variables, used mostly in business contexts, and then the revision designed to add emotional antecedents suitable to the consumer context. Hypotheses that incorporate all of the variables and the relationships among them are tested in a study of online auction consumer behavior, and support is found for the extended TAM. Findings thus reveal that the TAM is stable across contexts and that additional user variables help explain the acceptance of consumer technology use in personal scenarios. © 2008 Wiley Periodicals, Inc.
Leveraging sponsorships on the Internet: Activation, congruence, and articulation
Authors: Weeks Clinton S. , Cornwell T. Bettina , Drennan Judy C. 
Published: June 2008

AbstractThis paper considers how the Internet can be used to leverage commercial sponsorships to enhance audience attitudes toward the sponsor. Definitions are offered that distinguish the terms leverage and activation with respect to sponsorship‐linked marketing; leveraging encompasses all marketing communications collateral to the sponsorship investment, whereas activation relates to those communications that encourage interaction with the sponsor. Although activation in many instances may be limited to the immediate event‐based audience, leveraging sponsorships via sponsors' Web sites enables activation at the mass‐media audience level. Results of a Web site navigation experiment demonstrate that activational sponsor Web sites promote more favorable attitudes than do nonactivational Web sites. It is also shown that sponsorsponsee congruence effects generalize to the online environment, and that the effects of sponsorship articulation on audience attitudes are moderated by the commerciality of the explanation for the sponsor‐sponsee relationship. Importantly, the study reveals that attitudinal effects associated with variations in leveraging, congruence, and orientation of articulation may be sustained across time. © 2008 Wiley Periodicals, Inc.
Can consumers recognize misleading advertising content in a media rich online environment?
Authors: Mitra Anu , Raymond Mary Anne , Hopkins Christopher D. 
Published: June 2008

AbstractThe worldwide growth and acceptance of e‐commerce provides consumers with the opportunity to shop in computer‐mediated interactive environments that simulate direct product experience. However, the phenomenal growth in advertising on the Internet and marketers' ability to rapidly change the content of online ads also create concerns about consumers being exposed to a plethora of potentially misleading advertisements on the Internet. Relatively little research to date has focused on how consumer beliefs are shaped by online advertising claims or are affected by media richness. © 2008 Wiley Periodicals, Inc.
Voluntary self‐disclosure of information on the Internet: A multimethod study of the motivations and consequences of disclosing information on blogs
Authors: Lee Doo‐Hee , Im Seunghee , Taylor Charles R. 
Published: June 2008

AbstractAs marketing paradigms have shifted toward the need to build a relationship with consumers, marketers need to facilitate two‐way communications in order to better understand them. The ability of marketers to glean the types of detailed information needed often depends on the consumer's willingness to volunteer such information. Given consumer concern about privacy as well as skepticism about how marketers use data, it is important to understand how consumers make decisions with regard to self‐disclosure of information. In spite of the widespread concern about privacy, many consumers are willing to engage in significant disclosure of various aspects of their lives in an online context, most notably on blogs. The purpose of this study is to examine the psychological characteristics of consumers who engage in voluntary self‐disclosure. Through the use of the multimethod approach, we identify seven motivations individuals have for voluntary self‐disclosure, as well as three consequences of this behavior.We also examine the structural configurations of the relationship among motivations, voluntary self‐disclosure, and consequences. Results suggest that the motives identified help to explain why some individuals self‐disclose and that individuals perceive that there are three major consequences of self‐disclosure, two of which are positive. © 2008 Wiley Periodicals, Inc.
Cerebellar ataxia as a possible organ‐specific autoimmune disease
Authors: Hadjivassiliou Marios , Boscolo Sabrina , Tongiorgi Enrico , Grünewald Richard A. , Sharrack Basil , Sanders David S. , Woodroofe Nicola , Davies‐Jones G. Aelwyn B. 
Published: June 2008

AbstractThe purpose of this study was to investigate the possibility that autoimmunity is responsible for some cases of sporadic idiopathic ataxia. We prospectively investigated 400 patients with progressive ataxia and identified a group of patients with idiopathic sporadic ataxia. A comparison of the prevalence of autoimmune diseases, the autoimmunity linked HLA DQ2, and serum anticerebellar antibodies was made between patients with idiopathic sporadic and those with genetically characterized ataxia. Ninety‐one of 400 (23%) patients with progressive ataxia had idiopathic sporadic ataxia. The prevalence of autoimmune diseases in this group was 47% as compared with 6% in the group of patients with genetic ataxias (P < 0.0001). The HLA DQ2 was found in 71% of patients with sporadic ataxia, in 34% in patients with genetic ataxia, and in 36% of healthy local population (P = 0.0005 by Chi squared test). Anticerebellar antibodies were detected in 12 out of 20 patients with idiopathic sporadic as opposed to one of 20 patients with genetic ataxia. The significantly higher prevalence of autoimmune diseases, HLA DQ2 and anti‐cerebellar antibodies in patients with idiopathic sporadic ataxia compared to genetic ataxia supports the notion that autoimmunity may account for some cases of idiopathic sporadic cerebellar ataxia. © 2008 Movement Disorder Society
Chronic pain in Parkinson's disease: The cross‐sectional French DoPaMiP survey
Authors: Nègre‐Pagès Laurence , Regragui Wafa , Bouhassira Didier , Grandjean Héléne , Rascol Olivier 
Published: June 2008

AbstractPain is a frequent, but poorly studied symptom of Parkinson's disease (PD). DoPaMiP survey aimed to assess the prevalence of chronic pain in PD, to describe PD patients with chronic pain, and to record analgesic consumption. About 450 parkinsonian patients underwent structured standardized clinical examination and completed self‐reported questionnaires in a cross sectional survey. Pains related or unrelated to PD were identified according to predefined criteria. About 98 patients with other chronic disorders than PD were examined to assess if pain was more frequent in PD than in this population. Two thirds parkinsonian patients (278 of 450) had chronic pain. Twenty‐five patients with non‐chronic pain (<3‐month duration) were excluded from subsequent analysis. Twenty six percent (111 of 425) parkinsonian patients had pain unrelated to PD (“non‐PD‐pain”, caused mainly by osteoarthritis), while 39.3% (167 of 425) had chronic pain related to PD (“PD‐pain”). In this last group, PD was the sole cause of pain in 103 and indirectly aggravated pain of another origin (mainly osteoarthritis) in 64. Parkinsonian patients with “PD‐pain” were younger at PD onset, had more motor complications, more severe depressive symptoms than those without pain or with “non‐PD pain.” “PD‐pain” was more intense (P = 0.03), but was less frequently reported to doctors (P = 0.02), and was associated with less frequent analgesic consumption than “non‐PD‐pain.” Pain was twice more frequent in PD patients than in patients without PD after adjustment for osteo‐articular comorbidities (OR = 1.9; 95% CI 1.2–3.2). Chronic pain is frequent but underreported in PD. Awareness of this problem should be increased and the assessment of analgesic strategies improved. © 2008 Movement Disorder Society