bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyvinyl alcohol‐poly(caprolactone) Semi IPN scaffold with implication for cartilage tissue engineering
Authors: Mohan Neethu , Nair Prabha D. 
Published: July 2007

AbstractPolycaprolactone is an FDA approved aliphatic polyester that is widely used as a scaffold for tissue engineering. It is hydrophobic and doesn't have any reactive functional groups on the polymer for further modification. Blending with other hydrophilic polymers like polyvinyl alcohol helps to generate a hybrid polymer with better properties. In this study we have been able to fabricate a novel porous 3D scaffold of Semi‐IPN Poly (caprolactone)—Poly (vinyl alcohol). The Semi IPN is phase mixed and has synergistic properties of its constituent polymers. The hybrid scaffold is nontoxic and highly hydrophilic with greater percentage of swelling and is also amenable for further modification with bioactive peptides. Although porous with an open interconnected porous structure, the scaffold has adequate mechanical strength to withstand the load imparted by the cells during in vitro culture. Porcine chondrocytes seeded within the unmodified scaffolds secrete extra cellular matrix components revealing that the hybrid scaffold has immense potential for tissue engineering applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Effects of a peripheral enamel bond on the long‐term effectiveness of dentin bonding agents exposed to water in vitro
Authors: Reis Andre F. , Giannini Marcelo , Pereira Patricia N. R. 
Published: July 2007

AbstractThis study evaluated the effects of water exposure on the in vitro microtensile bond strength (μTBS) of etch‐and‐rinse and self‐etching adhesives to human dentin over a 1‐year storage period. Five adhesive systems used were as follows: a one‐step self‐etching adhesive (One‐up Bond F‐OB), two two‐step self‐etching primers (Clearfil SE Bond‐SE and Clearfil Protect Bond‐CP), and two etch‐and‐rinse adhesives (Single Bond‐SB and Prime&Bond NT‐PB). Dentin surfaces were bonded, restored, and assigned to four subgroups, according to the degree of water exposure: 24 h of peripheral water exposure (24 h‐PE) (having circumferential enamel); and 1 year of peripheral exposure (1 yr‐PE), direct exposure (1 yr‐DE) (dentin directly water‐exposed), or directly exposed to oil only (no water exposure) (1 yr‐DOE). A composite‐enamel bond adjacent to the restoration is determined if the water exposure was peripheral or direct. After storage periods, specimens were serially sectioned, trimmed to an hourglass shape with a cross‐sectional area of 1 mm2 at the interface, and tested in tension. Results were analyzed by two‐way ANOVA and Tukey test (α = 0.05). No difference was found between 24 h‐PE and 1 yr‐PE for OB, CP, SB, and PB. However, μTBS values significantly dropped after 1 yr‐DE for SE, CP, SB, and PB. A decreased μTBS was seen in SE after 1 yr‐PE, but no differences existed between 1 yr‐PE and 1 yr‐DE. Similar or increased μTBS values were noted in 1 yr‐DOE for all adhesives. Water‐storage for 1 year significantly decreased μTBS for all adhesives. However, except for SE, the presence of a peripheral composite‐enamel bond seemed to reduce the degradation rate in resin‐dentin interfaces for all materials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
The inhibition of the expression of the small Rho GTPase Rac1 induces differentiation with no effect on cell proliferation in growing human adult keratinocytes
Authors: Nikolova Ekaterina , Mitev Vanio , Minner Frédéric , Deroanne Christophe F. , Poumay Yves 
Published: July 2007

AbstractRac1 is a Rho subfamily small GTPase which is highly expressed in epidermal keratinocytes. In mice the significance of Rac1 for the maintenance of the epidermis has been controversial. In keratinocytes from human origin, the role of Rac1 in the control of growth/differentiation is still obscure. In this study we used RNA interference to induce specific inhibition of Rac1 expression in cultured human keratinocytes and analyzed the consequences on proliferation and differentiation. We found that the autocrine proliferation of keratinocytes is unaltered by Rac1 silencing. However, the suppression of Rac1 induced premature differentiation as revealed by the expression of markers (keratin 10, involucrin), but the involved mechanism is independent of the activity of p38 mitogen‐activated protein kinase. Rather, we found that the effects of Rac1 silencing on keratinocytes differentiation are concomitant with negative regulation of the Ser62/Thr58 phosphorylation on the transcription factor c‐myc, a mechanism known to control post‐translational stability of the c‐myc protein. Thus, in growing human keratinocytes, Rac1 could impede the expression of premature differentiation markers, probably by exerting positive control on c‐myc activity and its binding to specific promoters. J. Cell. Biochem. 103: 857–864, 2008. © 2007 Wiley‐Liss, Inc.
STI571 (Glivec®) affects histamine release and intracellular pH after alkalinisation in HMC‐1560, 816
Authors: Löber Kristin , Alfonso Amparo , Escribano Luis , Botana Luis M. 
Published: July 2007

AbstractThe human mast cell line (HMC‐1560, 816) was used to study the effect of the tyrosine kinase inhibitor STI571 (Glivec®) on exocytosis, intracellular Ca2+ and pH changes, because STI571 inhibits the proliferation of HMC‐1560 and induces its apoptosis. This drug does not have these effects on HMC‐1560, 816. Exocytosis in HMC‐1560, 816 cells can be stimulated by alkalinisation with NH4Cl as well as with ionomycin. Surprisingly 24‐h pre‐incubation with STI571 decreases spontaneous histamine release of HMC‐1560, 816 cells, but increases the histamine response after alkalinisation and not after ionomycin‐stimulation. After addition of NH4Cl, pHi has a higher increase in STI571 pre‐incubated cells, without changing intracellular Ca2+ concentration. Activation of PKC in combination with tyrosine kinase inhibition increases also histamine release in HMC‐1560, 816 cells. Strangely, STI571 pre‐incubated cells with PKC inhibited by rottlerin show the same effects. In these cells, cytosolic pH increases more than in control cells. This is the first report of STI571 effect in HMC‐1560, 816 cells. It seems that different pathways modulate signals for proliferation and exocytosis. STI571 does not only inhibit KIT TyrK, but may also influence cytosolic pH after alkalinisation in both cell lines, HMC‐1560 and HMC‐1560, 816, and this ends in induced histamine release. This work is important since HMC‐1560, 816 cells are reported in 80% of aggressive systemic mastocytosis cases and the understanding of some signalling pathways involved in mast cell response could facilitate drug targeting. J. Cell. Biochem. 103: 865–876, 2008. © 2007 Wiley‐Liss, Inc.
gp‐41 protein production by E. coli in unconventional bioreactor coupled with magnetic field generator
Authors: Justo Oselys Rodriguez , Pérez Victor Haber , Alvarez David Chacon 
Published: July 2007

AbstractBACKGROUND: In this work recombinant gp‐41 protein production by E. coli in an unconventional bioreactor coupled with a magnetic field generator was studied. The submerged fermentation process was carried out by fed‐batch operation, recycling the culture medium externally through a stainless steel spiral U‐shape tube inserted on the inside of a magnetic field generator. The exposure time and magnetic field induction were varied in a range from 1 to 12 h and 10 to 100 mT, respectively, according to a central composite design with centered face.RESULTS: It was found that the inhibitory or stimulatory effect of magnetic field on cell growth and protein production depended on exposure time and magnetic field strength. The production of recombinant gp41 protein was 20% higher than the control.CONCLUSION The procedure here presented could be an easy‐to‐use approach to improve the efficiency of recombinant protein production by E. coli. Copyright © 2007 Society of Chemical Industry
Anaerobic digestion of liquid dairy manure using a sequential continuous‐stirred tank reactor system
Authors: Wen Zhiyou , Frear Craig , Chen Shulin 
Published: July 2007

AbstractBACKGROUND: Anaerobic digestion of liquid manure from flush dairy operations is an alternative to manure management practices with environmental benefits and producing biogas. A unique sequential reactor system was used to study the anaerobic digestion (AD) of flush dairy manure with the aim of determining (1) the effects of organic strength of the influent on AD performance; (2) whether phase separation is beneficial to treatment and AD design; and (3) whether there is any difference between completely mixed and plug‐flow approaches to implementing the AD process.RESULTS: The influent with high organic strength resulted in higher levels of biogas production and chemical oxygen demand (COD)/solids removal. When the manure stream is used as influent for the anaerobic digestion, the phenomenon of two‐stage anaerobic digestion process does not exist because the stream contained high levels of alkalinity and volatile fatty acids. The biogas production and COD/solids destruction achieved by plug‐flow and completely mixed reactor were very similar when treating the liquid manure stream.CONCLUSION: The organic strength of the influent significantly influenced AD performance. The plug‐flow reactor and the completely mixed reactor had a similar AD performance. For the type of manure and organic loading rate investigated, the results give indications for designing an AD process in flush dairy operations. Copyright © 2007 Society of Chemical Industry
Collision‐induced dissociation of sulfur‐containing imidazolium ionic liquids
Authors: Lesimple Alain , He Xun , Chan Tak‐Hang , Mamer Orval 
Published: July 2007

AbstractA number of 1,2‐dimethylimidazole ionic liquids substituted on NII with alkyl chains of varying lengths terminated with sulfur‐containing groups were investigated by electrospray high‐resolution tandem Fourier‐transform mass spectrometry. Fragmentation pathways are strongly dependent on the oxidation state of the sulfur and the alkyl chain length. The dissociations detected are rationalized by deuterium labeling, comparisons between homologous compounds and accurate mass data. Several homolytic processes are reported, leading to distonic ions and loss of hydrogen, methyl and other free radicals. Copyright © 2007 John Wiley & Sons, Ltd.
Validated chiral separation of M9, a Mannich ketone compound, by chiral ligand‐exchange chromatography
Authors: Bi Yujin , Yang Jing , Lu Xiumei , Shao Taili , Dong Jinhua , Li Famei 
Published: July 2007

AbstractEnantioseparation of the Mannich ketone M9, a potential antifungal compound, was examined using chiral ligand‐exchange chromatography. The chiral mobile phase contained complexes of Cu(II) with the optically active selector L‐aspartame (APM) and the organic modifier methanol. The separation was optimized with respect to the concentration of the Cu(II)‐(L‐APM) complexes, pH of mobile phase, methanol content, and column temperature. A baseline separation (Rs = 3.08) was achieved for enantiomers of M9 under optimal conditions, and the analysis was accomplished in eleven minutes. The developed method was extensively validated. The sample stability, linearity, precision (method repeatability and intermediate precision) and accuracy, and the limits of detection and quantification of the developed method were studied. The proposed method was shown to be accurate and suitable for the quantitative determination of each enantiomer of M9.
Zum Einfluss des Schweißens auf das Kriechverhalten moderner Stähle für die thermische Energieerzeugung
Authors: Cerjak H. , Mayr P. 
Published: July 2007

AbstractUn‐ und niedriglegierte ferritisch/bainitische Chrom‐Stähle, sowie hochlegierte ferritisch/martensitische 9–12 % Chrom‐Stähle werden weltweit für Hochtemperatur‐Komponenten in der thermischen Energieerzeugung eingesetzt. Schweißen, in seiner gesamten Vielfalt, stellt nach wie vor die wichtigste Reparatur‐ und Fügetechnologie im Kraftwerksbau dar. Die Wärmeeinflusszone von Schweißverbindungen erweist sich oft als das schwächste Glied im Hochtemperaturbetrieb. Während un‐ und niedriglegierte Stähle eine gewisse Empfindlichkeit zur Bildung von Relaxationsrissen aufweisen können, versagen Schweißverbindungen hochlegierter ferritischer Chrom‐Stähle unter Kriechbelastung meist in der Feinkornzone aufgrund Type IV Crackings. Dieser Beitrag liefert eine Übersicht über den Einfluss des Schweißtemperaturzyklus auf die Mikrostruktur des Grundwerkstoffes. Das Langzeit‐Kriechverhalten von Schweißverbindungen wird direkt den häufigsten Fehlermechanismen gegenübergestellt und Auswirkungen für die Industrie bei der Verwendung hochwarmfester ferritischer Stähle werden erläutert.
Elektronenstrahlschweißen von Weichenherzen für den Gleisbau
Authors: von Dobeneck D. , Prikhodovsky A. , Ploshikhin V. 
Published: July 2007

AbstractZum Elektronenstrahlschweißen von hochkohlenstoffhaltigem Schienenstahl wurde mit Hilfe von Computersimulationen eine Prozesskette Schweißen – Wärmebehandlung entwickelt, die die Martensitbildung und damit die schnelle Aufhärtung verhindert.
Innovatives Elektronenstrahlschweißen hochschmelzender Metalle
Authors: Behr W. , Reisgen U. 
Published: July 2007

AbstractDas Forschungszentrum Jülich (FZJ) beschäftigt sich seit seiner Gründung als Kernforschungsanlage Jülich im Jahr 1956 mit der Materialbearbeitung von Sondermetallen. Hierzu zählen vor allem die hochschmelzenden Refraktärmetalle Niob, Molybdän und Wolfram. Das Elektronenstrahlschweißen gilt schon immer als innovatives Sonderschweißverfahren; im FZJ wurde es darüber hinaus stets an die wachsenden Anforderungen seitens der Forschungspartner sowie der beteiligten Fertigungs‐ und Konstruktionsbereiche angepasst. Von manueller Anlagentechnik bis zu modernster Mehrstrahltechnik wurde so immer das technisch Machbare für die Grundlagenforschung realisiert.
Einfluss der Beschichtungen beim stoffschlüssigen Lichtbogenfügen von Stahl mit Aluminium
Authors: Steiners M. , Höcker F. 
Published: July 2007

AbstractDie stoffschlüssige und anwendungsgerechte Verbindung zwischen Stahl und Aluminium ist ein bis heute nicht zufrieden stellend gelöstes Problem in der Fügetechnik. Die Probleme, diese Metalle miteinander thermisch zu fügen, liegen in der geringen bis nicht vorhandenen gegenseitigen Löslichkeit der Metalle im festen Zustand und der Ausbildung von spröden intermetallischen Phasen. Die Qualität der Fügeverbindung hängt von vielen Einflussfaktoren ab, die teilweise in Wechselwirkung zueinander stehen. Einer dieser Einflussfaktoren ist die Beschichtung der Stahlbleche. Am Beispiel von im Automobilbau gängiger und unüblicher Beschichtungen soll der Einfluss der Beschichtung und eines Flussmittels auf die Benetzungslänge und den Benetzungswinkel, bei ansonsten konstanten Randparametern, dargestellt werden. Die Ergebnisse sind Teil einer Untersuchungsreihe, die aktuell am Institut für Schweißtechnik und Fügetechnik in Aachen durchgeführt wird.
Three‐dimensional analytical magnetic resonance imaging phantom in the Fourier domain
Authors: Koay Cheng Guan , Sarlls Joelle E. , Özarslan Evren 
Published: July 2007

AbstractThis work presents a basic framework for constructing a 3D analytical MRI phantom in the Fourier domain. In the image domain the phantom is modeled after the work of Kak and Roberts on a 3D version of the famous Shepp‐Logan head phantom. This phantom consists of several ellipsoids of different sizes, orientations, locations, and signal intensities (or gray levels). It will be shown that the k‐space signal derived from the phantom can be analytically expressed. As a consequence, it enables one to bypass the need for interpolation in the Fourier domain when testing image‐reconstruction algorithms. More importantly, the proposed framework can serve as a benchmark for contrasting and comparing different image‐reconstruction techniques in 3D MRI with a non‐Cartesian k‐space trajectory. The proposed framework can also be adapted for 3D MRI simulation studies in which the MRI parameters of interest may be introduced to the signal intensity from the ellipsoid. Magn Reson Med, 2007. Published 2007 Wiley‐Liss, Inc.
Postoperative splinting after open carpal tunnel release does not improve functional and neurological outcome
Authors: Huemer Georg M. , Koller Matthias , Pachinger Thomas , Dunst Karin M. , Schwarz Barbara , Hintringer Thomas 
Published: July 2007

AbstractAlthough surgical division of the transverse carpal ligament is the operative treatment of choice for carpal tunnel syndrome (CTS), controversy exists about the immediate postoperative treatment regimen. Splinting for up to 6 weeks after surgery is recommended by some investigators. We therefore evaluated effectiveness of splinting after open carpal tunnel surgery by a randomized, controlled trial. Fifty consecutive patients with clinically and electrophysiologically confirmed idiopathic CTS were assigned to open carpal tunnel release and randomized to receiving a light bandage (25 patients) or a bulky dressing with a volar splint (25 patients) for 2 days each. All patients were followed up at 3 months. Parameters retrieved were pain as measured using a visual analog scale, two‐point discrimination, and grip strength, and nerve conduction studies. At follow‐up, all patients reported definite improvement of symptoms, but there was no statistically significant difference between the two groups for any of our outcome measures. Thus, postoperative splinting after open carpal tunnel release does not yield any benefit to eventual outcome. In fact, it adds to the overall operating time and can safely be abandoned. Muscle Nerve, 2007
Village viability assessment procedures in Tanzania: Decision‐making with curtailed information requirements
Authors: Belshaw D. G. R. 
Published: July 2007

AbstractThis article explains the methods developed for gathering necessary data to make assessments of village viability in Tanzania during the period 1975‐78. The need for methods arose out of the consolidation into villages of dispersed rural settlements and the problem encountered by an unknown number of new villages of deficiencies in the available and accessible physical environment. What was required was a means of identifying those villages where priority should be given to population resettlement and the identification of new village sites. The initial attempt at establishing a standard village viability assessment procedure involved devising a procedure which assumed the need for a high level of environmental data. This presupposed the use of staff with considerable expertise, and, given the scale of the problem, this expertise was not available. A revised procedure was therefore developed which was based on more realistic assumptions about what was available. This involved making fresh estimates about the level of expertise, the amount of assessment time available and the degree of data accuracy required. On the basis of field testing a revised approach was developed. The main features of this approach are outlined, and the merits of the approach discussed.
The former Western Nigeria Development Corporation: A framework for performance evaluation
Authors: Akinsanya A. 
Published: July 2007

AbstractThe performance of the Western Nigeria Development Corporation and its separate projects shows the limitations of profit and profitability as a basis for evaluation. Judged on the basis of profit most projects have been failures. The objectives stated for the corporation specify the fostering of economic development, but these are expressed in the law in such general terms that they do not provide alternative criteria on the basis of which the Corporation can be measured, and the Economic Plan of Western Nigeria in 1955 was similarly unspecific. The article argues that objectives should be specified in more precise terms, and that Corporations should be required to operate, thereafter, on business principles with unprofitable services paid for by government if provided at government's behest.
Rapid rural appraisal: Rationale and repertoire
Authors: Chambers Robert 
Published: July 2007

AbstractDecision makers need the right information at the right time but in rural development much information generated is too costly and inappropriate. Rapid rural appraisal forms part of the attempt to learn about rural conditions in a cost effective way. Such appraisal involves avoiding the traps of quick and dirty or long and dirty methods and using instead methods that are more cost effective. To do this means ignoring inappropriate professional standards and instead applying a new rigour based on the two principles of optimal ignorance—knowing what it is not worth knowing—and proportionate accuracy—recognising the degree of accuracy required. The article reviews a range of approaches and techniques for rapid rural appraisal that are less rigid and exhaustive than many traditional methods and yet more rigorous in relation to cost and use. Time is emphasized as a critical factor in effective appraisal and rapid rural appraisal methods increase the chance of reducing the bias against the poorer rural people in the promotion of rural development.
An appraisal of agro‐based cooperatives in Peninsular Malaysia
Authors: Wells R. J. G. 
Published: July 2007

AbstractThis appraisal of agro‐based cooperatives in Peninsular Malaysia assesses performance in relation to savings mobilization, rural credit, land development and the provision of marketing facilities. The article points to the limited extent of their achievement and argues that while the cooperatives have achieved less measurable goals, without improving their performance in relation to economic goals, they will be unable to achieve their social purpose.
In search of an anatomy of African administrators
Authors: Kirk‐Greene A. H. M. 
Published: July 2007

AbstractBy way of welcoming one of the first—and still too few—accounts by African administrators of what it was like to have served under two masters, one British and one African, the article first reviews the chronology of the literature on and by Africa's administrators. Starting from a survey of the history of the British Colonial Administrative Service and some of the recent memoirs of its members, a milestone in the literature is signalled by the shift in emphasis of public service commissions of enquiry away from primary concern with salaries and conditions of service to concerns with the positive Africanization of the civil services. The gradual responsibility of Africans themselves for such reports is then noted, often culminating in a recommendation for the establishment of an Institute of Public Administration.While the quantity and quality of insiders' literature by Africa's civil servants still falls short of that which has characterized the writing by Indian members of the former Indian Civil Service, the position has improved since the publication of the proceedings of the Inter‐African Public Administration seminars and by the noticeably less constrained comments by the bureaucracy during a period of military rule. The article concludes with a look at the Ife University project and calls for an extension of such primary research into African administration while the first, and historically unique, generation of African bureaucrats are still alive to record their memories and interpret their significance against subsequent analysis.