bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multicomponent Theory of the Cathodic Plasma Jet in Vacuum Arcs
Authors: Wieckert C.
Published: July 2007

It was demonstrated in many experiments, that the expansion of the dense plasma of a vacuum arc spot goes along with an acceleration of multiply charged ions in the direction of the anode. The resulting plasma jet is analysed in a stationary and quasi‐onedimensional model, that accounts for virtually all existing explanations. The corresponding system of multifluid equations includes singular points. The model is evaluated for two versions, that are suited to describe the cathodic jet and for which the singular points can be treated. The agreement with the experimentel results is satisfactory. It turns out, that the acceleration of the ions is mainly due to the electron‐ion friction. The results indicate, that the study of the plasma jet is a suitable tool to get a more detailed knowledge of the cathode spot.
Recombination of a Xenon Plasma Jet
Authors: Anders A.
Published: July 2007

As pointed out in a previous paper, stable spherical plasma configurations can be produced by pulsed injection of a plasma into an ambient gas. It is shown here that the observed long plasma lifetime of several milliseconds is in agreement with collisional‐radiative recombination theories. We used the modified diffusion approximation by Biberman et al. involving thermal non‐equilibrium, recombination heating of electrons, heat conduction, radiation and other details. Under the assumption of a pure xenon plasma, the calculated plasma lifetime is even longer than the observed one. This discrepancy can be explained by the presence of molecules and turbulent mixing with the outer gas, which are not considered in the recombination calculation.
Energy Balance of Low‐Voltage Spark Discharges
Authors: Apostol I. , Mihailescu I. N. , Buteikis R. , Nashlenas E. , Serapinas P.
Published: July 2007

In this work we are presenting an experimental and theoretical analysis of the energy balance of low‐voltage spark discharges. It is pointed out that the greatest part of the energy from the central hot plasma region is lost in the form of radiation, but the radiation from electrode particles (here aluminium) can be important, too.
Spark Discharge Action on a Cathode Surface in Air Atmosphere
Authors: Apostol I. , Mihailescu I. N. , Popa A. L. , Buteikis R. , Oberauskas J. , Serapinas P.
Published: July 2007

New results obtained by electron microscopy investigations of cathode spot parameters are qualitatively and quantitatively analysed to the view of further understanding of the cathode processes in spark discharges.
CD5+ B cells with the features of subepithelial B cells found in human tonsils
Authors: Dono Mariella , Burgio Vito Lelio , Colombo Monica , Sciacchitano Salvatore , Reverberi Daniele , Tarantino Vincenzo , Cutrona Giovanna , Chiorazzi Nicholas , Ferrarini Manlio
Published: July 2007

This study describes a CD5+ B cell that differs from the majority of the CD5+ B cells from human tonsils. This cell, isolated from in vivo activated B cells, expressed activation markers and featured a CD23–, IgMhigh, IgDlow surface phenotype, responded to T cell‐independent type‐2 antigens in vitro, and was detected in the subepithelial (SE) areas, the tonsil equivalent of the splenic marginal zone (MZ). Most of the cells utilized unmutated Ig VH genes, although cells with mutated genes also were found, a finding confirmed by single‐cell studies. Mutated sequences were more frequent in suspensions enriched for CD27+ cells. Repeated VDJ gene sequences were observed in different molecular clones from the same cell suspension, suggesting in situ expansion. These CD5+ B cells seem to share features with previously characterized tonsil CD5– SE B cells and differ from the majority of tonsil CD5+ B cells, which have the surface phenotype of follicular mantle B cells, lack activation markers, do not respond to T cell‐independent antigens, and utilize unmutated VH genes. These data are discussed considering the present views on the origin of B cell subset populations and the relationships between MZ and B1 cells.
Mediastinal lymph node CD8α− DC initiate antigen presentation following intranasal coadministration of α‐GalCer
Authors: Ko Sung‐Youl , Lee Kyoo‐A , Youn Hyun‐Jun , Kim Yeon‐Jeong , Ko Hyun‐Jeong , Heo Tae‐Hwe , Kweon Mi‐Na , Kang Chang‐Yuil
Published: July 2007

Our previous study revealed that α‐galactosylceramide (α‐GalCer) is a potent nasal vaccine adjuvant inducing both potent humoral and cellular immune responses and affording complete protection against viral infections and tumors. However, the antigen‐presenting cells (APC) that are activated by NKT cells and thereby initiate the immune responses following intranasal coadministration of protein antigen and α‐GalCer are poorly understood. We assessed here where antigen presentation occurs and which APC subset mediates the early stages of immune responses when protein antigen and α‐GalCer are intranasally administered. We show that dendritic cells (DC), but not B cells, initiated the mucosal immune responses at mediastinal lymph nodes. Of the DC subsets, the CD8α−B220−CD11c+ DC subset played the most prominent role in the direct and cross‐presentation of protein antigen to naive T cells and in triggering the naive T cells to differentiate into effector T cells. This might be mainly caused by a relatively larger population of CD1dhigh cells of CD8α−B220−CD11c+ DC subset than those of other DC subsets. These results indicate that CD8α−B220−CD11c+ DC is the principal subset becoming immunogenic after interaction with NKT cells and abrogating tolerance to intranasally administered protein antigen when α‐GalCer is coadministered as a nasal vaccine adjuvant.
Novel Ruthenium(II) N‐Heterocyclic Carbene Complexes as Catalyst Precursors for the Ring‐Opening Metathesis Polymerization (ROMP) of Enantiomerically Pure Monomers: X‐ray Structures, Reactivity, and Quantum Chemical Considerations
Authors: Buchmeiser Michael R. , Wang Dongren , Zhang Yan , Naumov Sergej , Wurst Klaus
Published: July 2007

Four chiral, enantiomerically pure monomers, exo,exo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valine ethyl ester (exo‐1),endo,endo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valineethyl ester (endo‐1), exo,exo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valine‐tert‐butylamide (exo‐2), and endo,endo‐N,N‐(norborn‐5‐ene‐2,3‐dicarbimido)‐L‐valine‐tert‐butylamide (endo‐2), were subjected to ring‐opening metathesis polymerization (ROMP) with Ru(CF3CO2)2(IMesH2)(p‐cymene) (3), Ru(CF3CO2)2(IMes)(p‐cymene) (4), RuCl2(IMes)(p‐cymene) (5), Ru(PCy3)(CF3CO2)2(p‐cymene) (6), Ru(CF3CO2)2(p‐cymene)·CF3COOAgPCy3 (6a), Ru(CF3CO2)2(PPh3)(p‐cymene) (7), Ru(CF3CO2)2(IMes)(PhNC)3 (8), and Ru(CF3CO2)2(IMesH2)(PhNC)3 (9) (IMes = 1,3‐dimesitylimidazol‐2‐ylidene, IMesH2 = 1,4‐dimesityl‐4,5‐diyhdroimidazolin‐2‐ylidene, PCy3 = tricyclohexylphosphane). X‐ray structures of precatalysts 3 and 6–9 are presented. Compounds 3 and 4 displayed significant ROMP activity, allowing for the controlled, yet nonliving synthesis of the corresponding polymers with polydispersity indices (PDIs) in the range of 1.17–2.14. In all cases the exo isomers of compounds 1 and 2 were polymerized by preference. While poly(endo‐1) was formed in an all‐trans form, poly(exo‐1) and poly(exo‐2) were produced in their cis/trans forms with a cis content of around 40 %. Calculations carried out at the B3LYP/LACVP* level suggest two possible mechanisms for the increased reactivity of the 2,3‐R2‐exo,exo isomers of norborn‐5‐ene‐2,3‐dicarbimido derivatives resulting in the formation of the ROMP‐active RuIV alkylidene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Fast Screening for the Purification of Proteins Using Membrane Adsorber Technology
Authors: Harkensee D. , Kökpinar Ö. , Walter J. , Kasper C. , Beutel S. , Reif O.‐W. , Scheper T. , Ulber R.
Published: July 2007

New membrane systems for the purification of proteins are presented. These disposable devices enable time saving screenings of downstream conditions with a small amount of protein solution. Furthermore, scaling up to the production level is directly possible since devices with effective membrane surfaces from 10 cm2 to 1 m2 are available. Several membranes like ion exchange membranes were investigated for the determination of protein binding capacities. Metal chelate membranes were used for ligand binding, which enables the determination of the membrane systems potential for affinity chromatography. Lysozyme and BSA are chosen for the determination of binding capacities of ion exchange membranes. Furthermore, Con A membranes, suitable for the isolation of glycoproteins, were developed and their binding properties were tested.
At‐line Monitoring of Bioprocess‐Relevant Marker Genes
Authors: Pioch D. , Jürgen B. , Evers S. , Maurer K.‐H. , Hecker M. , Schweder T.
Published: July 2007

The efficiency of an industrial bioprocess depends above all on the physiology of the host organism. Therefore, a rapid and direct analysis of the host's physiology during fermentation processes would be a worthwhile tool to improve the control of such bioprocesses in the future. This could be achieved by monitoring process‐relevant marker genes, the expression of which indicates unfavorable growth conditions. Recently it was shown that electrical DNA‐chips in combination with a magnetic bead‐based sandwich hybridization (BBSH) assay are a suitable alternative technique for a fast analysis of gene expression by monitoring the respective mRNA. In the present study, an improved protocol was established that allows for a shorter but still sensitive detection of specific mRNAs. The presented optimized BBSH protocol in combination with an electrochemical readout system was successfully applied for the analysis of Bacillus licheniformis marker genes indicating glucose‐ (acoA), nitrogen‐ (glnA) and phosphate‐ (phy, pstS) starvation. The expression profiles determined for all marker genes corresponded with the respective real‐time RT‐PCR measurements. Thus, the optimized protocol, in combination with the electrical chip, could provide the basis for a continuous at‐line monitoring of such biomarkers during bioprocesses.
Nonselective DNA damage induced by a replication inhibitor results in the selective elimination of extrachromosomal double minutes from human cancer cells
Authors: Shimizu Noriaki , Misaka Naomi , Utani Koh‐ichi
Published: July 2007

Gene amplification plays a pivotal role in human malignancy. Highly amplified genes frequently localize to extrachromosomal double minutes (dmin), which usually segregate to daughter cells in association with mitotic chromosomes. We and others had shown that treatment with low‐dose hydroxyurea (HU) results in the elimination of dmin and reversion of the cancer cell phenotype. HU treatment in early S‐phase, when dmin are replicated, results in their detachment from chromosomes at the next M‐phase, leading to the appearance of micronuclei enriched in dmin, followed by their elimination. In this article, we examined the effect of low‐dose HU on the behavior of dmin in relation to DNA damage induction by simultaneously monitoring LacO‐tagged dmin and phosphorylated histone H2AX (γH2AX). As expected, treatment with low‐dose HU induced numerous γH2AX foci throughout the nucleus in early S‐phase, and these rarely coincided with dmin. Most chromosomal γH2AX foci disappeared by metaphase, whereas, unexpectedly, those that persisted frequently associated with dmin. We found that these dmin aggregated, detached from anaphase chromosomes, and apparently formed micronuclei. Because γH2AX foci likely represent DNA double strand breaks (DSBs), the response to DSBs sustained by extrachromosomal dmin appears to be different from that sustained by chromosomal loci, which may explain why DSB‐inducing agents cause the selective elimination of dmin. © 2007 Wiley‐Liss, Inc.
Analysis of multiple SNPs in genetic association studies: comparison of three multi‐locus methods to prioritize and select SNPs
Authors: Heidema A. Geert , Feskens Edith J.M. , Doevendans Pieter A.F.M. , Ruven Henk J.T. , van Houwelingen Hans C. , Mariman Edwin C.M. , Boer Jolanda M.A.
Published: July 2007

Nonparametric approaches have been developed that are able to analyze large numbers of single nucleotide polymorphisms (SNPs) in modest sample sizes. These approaches have different selection features and may not provide similar results when applied to the same dataset. Therefore, we compared the results of three approaches (set association, random forests and multifactor dimensionality reduction [MDR]) to select from a total of 93 candidate SNPs a subset of SNPs that are important in determining high‐density lipoprotein (HDL)‐cholesterol levels. The study population consisted of a random sample from a Dutch monitoring project for cardiovascular disease risk factors and was dichotomized into cases (low HDL‐cholesterol, n = 533) and non‐cases (high HDL‐cholesterol, n = 545) based on gender‐specific median values for HDL cholesterol. Clearly, all three approaches prioritized three SNPs as important (CETP Taq1B, CETP−629 C/A and LPL Ser447X). Two SNPs with weaker main effects were additionally prioritized by random forests (APOC3 3175 G/C and CCR2 Val62Ile), whereas MTHFR 677 C/T was selected in combination with CETP Taq1B as best model by MDR. Obtained p‐values for the selected models were significant for the set association approach (p =.0019), random forests (p<.01) and MDR (p<.02). In conclusion, the application of a combination of multi‐locus methods is a useful approach in genetic association studies to select a well‐defined set of important SNPs for further statistical and epidemiological interpretation, providing increased confidence and more information compared with the application of only one method. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Efficient intermediate fine mapping: confidence set inference with likelihood ratio test statistic
Authors: Sinha Ritwik , Luo Yuqun
Published: July 2007

In positional cloning of disease causing genes, identification of a linked chromosomal region via linkage studies is often followed by fine mapping via association studies. Efficiency can be gained with an intermediate step where confidence regions for the locations of disease genes are constructed. The confidence set inference [CSI; Papachristou and Lin, 2006b] achieves this goal by replacing the traditional null hypothesis of no linkage with a new set of null hypotheses where the chromosomal position under consideration is in tight linkage with a trait locus. This approach was shown to perform favorably compared with several competing methods. Using the duality of confidence sets and hypothesis testing, CSI was proposed for the Mean test statistics with affected sibling pair data (CSI‐Mean). We postulate that more efficient confidence sets will result if more efficient test statistics are used in the CSI framework. One promising candidate, the maximum LOD score (MLS) statistic, makes maximum use of available identity by descent information, in addition to handling markers with incomplete polymorphism naturally. We propose a procedure that tests the CSI null hypotheses using the MLS statistic (CSI‐MLS). Compared with CSI‐Mean, CSI‐MLS provides tighter confidence regions over a range of single and two‐locus disease models. The MLS test is also shown to be more powerful than the Mean test in testing the CSI null over a wide range of disease models, the advantage being most pronounced for recessive models. In addition, CSI‐MLS is computationally much more efficient than CSI‐Mean. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Heterotopic parathyroid inclusion in a cervical lymph node
Authors: Veras Emanuela , Sturgis Erich M. , Luna Mario A.
Published: July 2007

Background.

During the pathologic examination of neck dissection specimens, unexpected findings within the lymph nodes may be discovered. Such findings may include benign epithelial inclusions, a second primary tumor, or chronic inflammatory diseases.

Methods.

We report a case of a 59‐year‐old man who underwent a laryngectomy and bilateral neck dissection for a right transglottic squamous carcinoma of the larynx. During the procedure, a large lymph node measuring 2.5 × 2.2 × 0.8 cm was found at the right level IV.

Results.

Histologic examination of the neck dissection specimen revealed benign parathyroid inclusions in the enlarged lymph node. The heterotopic cells expressed parathyroid hormone. This case represents a unique example of heterotopic parathyroid inclusions in a cervical lymph node.

Conclusion.

Parathyroid tissue should be included in the differential diagnosis of cervical intranodal epithelial inclusions. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Crosslinked hyaluronan with a protein‐like polymer: Novel bioresorbable films for biomedical applications
Authors: Pitarresi G. , Palumbo F. S. , Calabrese R. , Craparo E. F. , Giammona G.
Published: July 2007

In this work, novel hydrogel films based on hyaluronan (HA) chemically crosslinked with the α,β‐poly(N‐2‐hydroxyethyl) (2‐aminoethylcarbamate)‐D,L‐aspartamide (PHEA–EDA) were produced by solution casting method. The goal was to exploit both the biological key role of HA in tissue repair and regeneration, and the versatility of a synthetic protein‐like polymer as the PHEA–EDA, in order to obtain biomaterials with physicochemical and biological properties suitable for a clinical use. By varying the molar ratio between the PHEA–EDA amino groups and HA carboxyl groups, three different films were obtained and characterized. Particularly FTIR, swelling, hydrolysis, and enzymatic degradation studies were performed. In addition, the cytocompatibility of HA/PHEA–EDA hydrogel films was evaluated using human derm fibroblasts, by means of MTT and trypan blue exclusion assays. The high swelling capability, the long‐term hydrolysis resistance, and the resistance to hyaluronidase greater than that of only HA, together with the cell compatibility, have suggested the potential application of these novel HA‐based hydrogel films in the biomedical field of tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Hydroxyapatite‐coated polyurethane for auricular cartilage replacement: An in vitro study
Authors: Chetty Avashnee , Steynberg Tenille , Moolman Sean , Nilen Roger , Joubert Annie , Richter Wim
Published: July 2007

Auricular reconstruction remains a major challenge facing reconstructive surgeons owing to the complexity of autogenous transplants. In this study, the development of a three‐dimensional custom‐made polyurethane (PU) auricular implant with hydroxyapatite (HA) coating is described. The PU implant was produced by computerized tomography (CT) scanning and indirect rapid prototyping. To improve the physiological response of the implant, the PU prototype was coated with a microrough, homogenous layer of HA by a novel solvent‐compression coating method. Bioactivity of the HA coated PU substrates was confirmed by apatite formation on the HA coating after 9 days in revised simulated body fluid (pH 7.4). Adhesion strength of the HA coating to the PU surface using the tensile pull‐off test revealed partial failure of the coating with an average tensile strength of 1.6 MPa. As an initial stage indication of cytocompatibility for a soft tissue application, in vitro cell culturing on the HA‐coated PU substrates using Graham 293 fibroblast cells was performed. After 24 and 72 h, the HA coated surfaces displayed significantly higher cell numbers and metabolically active cells compared with the virgin uncoated PU surfaces. This indicates that HA coated PU surfaces are cytocompatible towards fibroblasts and could potentially be applied to auricular cartilage tissue replacement. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Uniform deposition of protein incorporated mineral layer on three‐dimensional porous polymer scaffolds
Authors: Segvich Sharon , Smith Hayes C. , Luong Linh N. , Kohn David H.
Published: July 2007

Inorganic–organic hybrid materials designed to facilitate bone tissue regeneration use a calcium phosphate mineral layer to encourage cell adhesion, proliferation, and osteogenic differentiation. Mineral formed on porous materials is often discontinuous through the thickness of the scaffold. This study aimed to uniformly coat the pores of three‐dimensional (3D) porous, polymer scaffolds with a bone‐like mineral layer in addition to uniformly incorporating a model protein within this mineral layer. A filtration system designed to induce simulated body fluid flow through the interstices of 3D polylactic‐co‐glycolic acid scaffolds (10‐mm diameter × 2‐mm thickness) illustrated that a uniform, continuous mineral layer can be precipitated on the pore surfaces of a 3D porous structure within 5 days. MicroCT analysis showed increased mineral volume percent (MV%) (7.86 ± 3.25 MV%, p = 0.029) and continuous mineralization of filtered scaffolds compared with two static control groups (floating, 0.16 ± 0.26 MV% and submerged, 0.20 ± 0.01 MV%). Furthermore, the system was effective in coprecipitating a model protein, bone sialoprotein (BSA), within the mineral layer. A 10‐fold increase in BSA incorporation was seen when coprecipitated filtered scaffolds (1308 ± 464 μg) were compared to a submerged static control group (139 ± 45 μg), p < 0.001. Confocal microscopy visually confirmed uniform coprecipitation of BSA throughout the thickness of the filtration scaffolds. The designed system enables 3D mineralization through the thickness of porous materials, and provides the option of including coprecipitated biomolecular cues within the mineral layer. This approach of providing a 3D conductive and osteoinductive environment could be conducive to bone tissue regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Use of biosurfactant in the removal of oil from contaminated sandy soil
Authors: Santa Anna Lídia M , Soriano Adriana U , Gomes Absai C , Menezes Emerson P , Gutarra Melissa LE , Freire Denise MG , Pereira Nei
Published: July 2007

The effectiveness of cell‐free rhamnolipid biosurfactant, derived from the culture medium at the end of fermentation was investigated for the removal of two different kinds of oil from contaminated sandy soils. The crude cultivation medium, containing 13.2 g L−1 of rhamnolipids, had a surface tension, interfacial tension and critical micellar concentration of 30 mN m−1, 2 mN m−1 and 60 mg L−1, respectively. The evaluation of biosurfactant in the culture medium (BM) and oil concentrations in the removal of oil from different contaminated sandy soil was performed using a statistical experimental design tool. Oil in sandy soil, containing predominantly aromatic or paraffinic hydrocarbons (5 to 10% w/w), was removed by as much as 91 and 78%, respectively, in the presence of reduced amounts of BM (6.3 to 7.9 g L−1). The progress of oil removal was monitored for 101 days and results indicated that removal efficiency in sandy soil with aromatic characteristics was relatively stable over the entire period. Based on these studies, it is concluded that use of a BM was effective in reducing oil concentrations in contaminated sandy soil. Copyright © 2007 Society of Chemical Industry
Comparative study on corrosion protection properties of electroless Ni‐P‐ZrO2 and Ni‐P coatings on AZ91D magnesium alloy
Authors: Song Y.W. , Shan D.Y. , Han E.H.
Published: July 2007

Electroless Ni‐P‐ZrO2 and Ni‐P coatings on AZ91D magnesium alloy were prepared, and their corrosion protection properties were compared in this paper. The potentiodynamic curves and electrochemical impedance spectroscopy (EIS) of the coated magnesium alloy in 3.5% NaCl solution showed that the corrosion performance of Ni‐P‐ZrO2 composite coating was superior to that of Ni‐P coating. The same conclusion was obtained with salt spray and immersion tests. The corrosion morphologies of two kinds of coatings with various immersion time intervals in 3.5% NaCl solution indicated that most corrosion products concentrated on the nodules boundaries of Ni‐P coating and blocked corrosion pit was the main corrosion form. For the Ni‐P‐ZrO2 coating, tortuous nodules boundaries were not the weak sites of the coating and corrosion initiated from the nickel phosphor alloy around the nanometer powders. Open corrosion pits occurred on the composite coating surface, and the coating was corroded gradually. Thus, the Ni‐P‐ZrO2 coating exhibited better corrosion protection property to magnesium alloy substrate than Ni‐P coating.
Korrosionsverhalten des Stahls WL 1.3964
Authors: Dinnebier H. , Schneider J.
Published: July 2007

Der nichtmagnetisierbare austenitische Stahl X 2 CrNiMnMoNNb 21 16 5 3, WL 1.3964, wird bei der Bundesmarine für den Sonderschiffbau, also für U‐Boote und Minenkampfboote eingesetzt. Hauptgrund für diese Anwendung ist neben seiner guten Korrosionsbeständigkeit sein vollständig amagnetisches Verhalten. Der Stahl WL 1.3964 ist auf freier Fläche in Meerwasser stabil; allerdings weist er eine wenn auch geringe Anfälligkeit gegenüber Loch‐ bzw. Spaltkorrosion auf. Auf Basis dieser Anfälligkeit gegenüber bestimmten Korrosionsformen wurde folgendes Untersuchungsprogramm definiert: Dauertauchversuche mit unbeschichteten und verschiedenartig beschichteten Proben in natürlichem Meerwasser, Spaltkorrosionsversuche und elektrochemische Untersuchungen mit verschiedenen Oberflächenzuständen bei verschiedenen Temperaturen. Als Ergebnis sind folgende Punkte festzuhalten: Der Stahl WL 1.3964 kann ungeschützt nicht in Meerwasser eingesetzt werden, da er prinzipiell eine gewisse Anfälligkeit gegenüber Loch‐ aber auch Spaltkorrosion besitzt. Ein zinkstaubhaltiges Beschichtungssystem kann den Werkstoff vor Korrosion schützen. Der Stahl WL 1.3964 besitzt eine erhöhte Anfälligkeit in aufgeschmolzenen Bereichen bzw. in Bereichen mit Anlauffarben, die nicht ordnungsgemäß nachbehandelt wurden.
Schweißen von Hohlstrukturen und offenporösen Metallschäumen für den Einsatz in Kombi‐Kraftwerken
Authors: Harms A. , Longerich S.
Published: July 2007

Für Anwendungen im Bereich neuartiger Kühlkonzepte von Dampf‐ bzw. Gasturbinen werden im Rahmen des Sonderforschungsbereichs 561 „Thermisch hochbelastete, offenporige und gekühlte Mehrschichtsysteme für Kombi‐Kraftwerke”︁ Fügetechnologien für Sandwich‐Hohlstrukturen und offenporöse Schäume untersucht.

Die Forschungsmotivation sowie die Anwendungsgebiete der verschiedenen Strukturen werden kurz umrissen. Die Schweißverfahren und ‐strategien zur Herstellung dieser Strukturen werden beschrieben, ebenso die fügetechnischen Besonderheiten. Abschließend werden die zur Weiterentwicklung der Verfahren und Strukturen geplanten Arbeiten aufgezählt.
Auftraglöten zum Verschleißschutz von Titanwerkstoffen
Authors: Bobzin K. , Ernst F. , Nickel R. , Rösing J. , Rojas Y.
Published: July 2007

Titan und Titanlegierungen weisen hohe spezifische Festigkeiten bis zu einer Temperatur von ca. 600 °C auf, verbunden mit einer ausgezeichneten Korrosionsbeständigkeit [1]. Ein entscheidendes Hindernis für den noch breiteren Einsatz stellt allerdings die geringe Verschleißbeständigkeit dar. Insbesondere sind Titanwerkstoffe gegenüber Reibermüdung und Erosionsverschleiß anfällig. Um dieser technischen Einschränkung zu begegnen, müssen Beschichtungsverfahren entwickelt werden. Einen vielversprechenden Ansatz stellt hierbei das Auftraglöten dar. Hartstoffe gemischt mit Loten auf Silber‐ und Titanbasis wurden im Hochvakuumofen gelötet und charakterisiert. Die Verschleißbeständigkeit wurde mit Ball‐on‐Disk‐Untersuchungen quantifiziert und optimiert.
Eigenschaften langzeitgealterter, artgleicher Schweißnähte der Ni‐Basislegierung alloy 602 CA
Authors: Zinke M. , Herold H. , Schneider H.
Published: July 2007

Der Beitrag stellt Untersuchungsergebnisse zum Einfluss einer zweijährigen industriellen Betriebsbeanspruchung im Produktionskreislauf der Ammoniaksynthese auf das Mikrogefüge und die mechanisch‐technologischen Eigenschaften von artgleichen WIG‐ und E‐Hand‐Schweißnähten der hochwarmfesten Nickel‐Basis‐Legierung alloy 602 CA (NiCr25FeAlY, Werkstoff‐Nr. 2.4633 / UNS N 06025) vor. Diese Ergebnisse zeigen, dass alloy 602 CA über eine sehr gute Beständigkeit gegenüber Metal Dusting verfügt. Darüber hinaus werden typische metallurgische Besonderheiten beim Schweißen dieser extrem heißrissempfindlichen Legierung vorgestellt und Empfehlungen für ein heißrisssicheres Verarbeiten von Bauteilen aus dieser Legierung gegeben.
What ails property tax?
Authors: Freeman Roger A.
Published: July 2007

Exemptions, rate limitations, assessment practices found among chief shortcomings of administration.
The Zambian administrative reforms: An alternative view
Authors: Chikulo B. C.
Published: July 2007

In 1968 administrative reforms were announced in Zambia which have been interpreted as involving a commitment to decentralization. The announcement came against a background of moves to strengthen party control over the bureaucracy, and a feature of the reforms was the reinforcement of this control. Subsequent developments have been characterized by the establishment of greater control over governmental administration in provinces and districts by party political appointees and by closer control over local party officials by party appointees from the centre. These developments have not been accompanied by decentralization within ministries, and functional ministries retain control over their field agents.
The revenue position of local government in Nigeria
Authors: Smith B. C.
Published: July 2007

Financial viability has been presented officially as crucial to the success of the sweeping reforms of local government in Nigeria and this article reviews the situation facing the new local government councils four years after the reforms were instituted. It sets the present situation against a background of past trends in which local government was financially dependent on regional and state governments, and subjected to increasingly detailed controls. Reviewing the present continuing dependence on state and federal government for finance, the limited use made of independent revenue bases, and the political and administrative factors militating against financial viability, the article argues that local government cannot escape from the vicious circle of underdevelopment.
The role of monitoring and evaluation in project planning, in relation to the upgrading of unauthorized housing areas
Authors: Rakodi Carole
Published: July 2007

This paper explores the role of monitoring and evaluation in the planning process with reference to urban development projects, especially those concerned with the upgrading of unauthorized housing areas. Monitoring, it is suggested, may be separated from evaluation, which may itself be subdivided into ongoing or formative and ex post or summative evaluation, and definitions of these terms are offered. Potential audiences for monitoring and evaluation research are identified and their interests discussed. Monitoring and evaluation requirements in relation to upgrading projects are then analysed in more detail, in terms of organizational requirements, methodology, and the utilization of findings. The discussion is illustrated with examples of the monitoring and evaluation systems established in upgrading projects in Zambia, Indonesia and the Philippines. Finally, some of the substantive issues which are relevant to the evaluation of upgrading are outlined and briefly discussed. These include the efficiency of project implementation, progressive development and self help construction as a means of increasing the low cost housing stock, community participation in planning and implementation, affordability and project impact.
Provident funds in the third world: A cross‐national review
Authors: Dixon John
Published: July 2007

Provident funds have been introduced in twenty third world countries as a way of meeting a need for social security. This article provides a careful comparative review of these funds, describing who they cover, how contribution rates are specified and on whom they fall, the rights the funds confer and how the funds are managed. The article points out that the provident funds have proved to be important financial institutions, valued by governments as instruments for mobilizing savings, but none has found a way of achieving the goal of providing adequate social security protection on the basis simply of compulsory savings.
Social analysis, project development and advocacy in U.S. foreign assistance
Authors: Morgan E. Philip
Published: July 2007

In 1975 the U.S. Agency for International Development (AID), the principal administrative agent for American bilateral development assistance, mandated a social analysis component to the project preparation and approval process.1 Although 'social soundness analysis' is now a required dimension of project identification and design its presumed positive effects are not yet apparent on the output side. Post project impact evaluations reveal that there continue to be negative social effects from AID'S development efforts, regardless of project type.

In the process by which projects are identified, framed, approved, and ultimately implemented, important signals identified by pre‐project social analysis get displaced. This occurs because anticipating social impact is only one of several goals or functions served by pre‐project design analysis. This essay interprets the role of social analysis in the dynamics of project preparation, identifying structures and procedures which attenuate its influence.
Strengthening rural development management through international assistance projects
Authors: Wunsch James S.
Published: July 2007

The importance of project management is well recognized and the favoured approach to improving management is to discard classroom based, technical transfer models of management development and develop training of direct relevance to field responsibilities. This article highlights the importance of recognizing in aid assisted projects that development projects serve some bureaucratic interests and hurt others with the consequence that projects need to be designed so as to maximize those interests which support its goals. The article is built around a case study of an Agricultural Management Development project in Ghana, begun in 1975 and appraised by a team led by the author in 1979. The appraisal revealed considerable achievements but also focused on facets where there were significant difficulties. These difficulties can be understood and explained in terms of the bureaucratic political interests in the Ministry of Agriculture which stood to lose from the development project, and the author indicates how the project itself could have been assisted by adding to it incentives which made the success of the project attractive to additional bureaucratic interests.
Expectancy theory in developing nations: Motivating Botswana public servants
Authors: Mueller Keith J.
Published: July 2007

The degree to which individuals are motivated to apply themselves depends in part on how far they expect to be able to achieve given goals. This study, based on interviews of local government administrators in Botswana, not only stresses the importance of expectancy in motivation but reports the importance of altruistic goals among these administrators. Among those interviewed there was a strong desire to advance their own careers, both by developing themselves in the job they currently hold, and by advancing through the organizational hierarchy. Employees, however, were also anxious to accomplish concrete objectives in their current jobs and thus to contribute to the development of the nation. Here unless officials have the expectancy of being able to achieve these goals their motivation is affected. Thus emphasis is placed in this article on the need to supplement traditional attention to pay and promotion as devices to improve motivation with a concern to remove road blocks to development. The enquiry thus strengthens the case for the performance improvement programme of the United Nations.
Projects as instruments of development administration: A qualified defence and suggestions for improvement
Authors: Rondinelli Dennis A.
Published: July 2007

Projects have become an important instrument of international assistance and of development administration because they seem to offer major advantages over other forms of planning and management. But projects have also come under increasing criticism in recent years. The benefits they offer to various interests involved in development ensure, however, that they are unlikely to be abandoned or to diminish in importance in the near future. Thus, ways must be found to make them more flexible and responsive methods of planning and managing social and human development activities. This can be done by planning, appraising and implementing projects as policy experiments, making their design and administration more learning‐oriented, and using them as instruments of strategic planning and management.
Building institutional capacity for policy analysis: An alternative approach to sustainability
Authors: Bremer Jennifer Ann
Published: July 2007

The project approach to development assistance has been criticized for failing to build lasting capacity. The problem lies not in the project approach itself, but in a failure to understand the constraints to capacity development and a consequent misdirection of effort. Policy analysis capacity is developed as an example. Policy analysis requires skills and abilities that public sector institutions in developing countries cannot sustain, owing to a combination of structural and organizational factors, among which personnel constraints are key. These factors inhibit the effectiveness of the standard approach, which seeks to establish analytic capacity within a specialized government unit (‘internal’ capacity). An alternative approach is to build ‘process’ capacity—the ability to get analysis done by other institutions, rather than the ability to do analysis internally. The author concludes that project strategies should be redirected toward a greater emphasis on building process capacity as a useful adjunct to internal capacity.
Decentralization, provincial policy making and the law in Papua New Guinea
Authors: Axline W. Andrew
Published: July 2007

Shortly after independence in 1975 Papua New Guinea decided to decentralize political power by creating nineteen provincial governments, complete with legislatures and executives. The division of powers between the two levels of government was set down in the Organic Law on Provincial Government and subsequent delegations of power by the National Executive Council (cabinet). The ability of provincial governments to fulfil the role in policy making set out for them depends on a number of political, financial and legal factors at both the national and provincial levels. A close examination of the legal base of provincial policy making reveals a number of shortcomings and incoherencies in the legal arrangements which pose obstacles to the realization of effective decentralized policy making. There are several possible approaches to resolving these problems, but the most appropriate one requires co‐ordination between the National Government and provincial governments in replacing delegated powers with provincial legislation.
The planning and management of integrated rural development in Drylands: Early lessons from Kenya's arid and semi‐arid lands programmes
Authors: Wiggins Steve
Published: July 2007

In Kenya a new generation of area‐based, multisectoral rural development programmes has been started, targetted on the country's extensive arid and semi‐arid lands (ASAL). By mid 1983, six such programmes were operational, each supported by a foreign donor and implemented by the Government of Kenya. Six years after the detailed planning of the first programme began, the record looks patchy. District level planning and co‐ordination hold promise, and some programme activities are going well. However, problems of slow and cumbersome planning and mobilization, a lack of community involvement in planning, too few technical successes, and remote prospects for institutionalizing the programmes if and when expatriate support is withdrawn are apparent. Behind these problems lie a number of basic obstacles, including the structure and orientation of the government's lack of support for the drylands among politicians, and the technical difficulties of raising dryland production. Faced with these obstacles, the ASAL programmes look set to run into continuing problems. Overcoming them will depend on both the success of recent government moves to deconcentrate, and patient support from both the government and the donors. Historically the prospects for such support are poor.
Managerial roles for social development management
Authors: Brinkerhoff Derick W.
Published: July 2007

The configuration of roles needed for effective management of social development is discussed and compared with that needed for conventional development project management. It is argued that while the managerial skills associated with more conventional projects are useful to social development managers, social development management places greater emphasis on entrepreneurial behaviour and attention to both analysing and influencing the environment external to the organization. Facilitating the creation of local‐level capacity also requires strong interpersonal skills. The extent to which social development management skills can be trained for is discussed, with an illustration from Sri Lanka. A combined skills training plus job rotation approach to preparing social development managers is suggested. The need to modify organizational structures and incentive patterns in order to effectively support new management skills is highlighted.
The politics of local government reform in rural Bangladesh
Authors: Huque Ahmed S.
Published: July 2007

Several changes have been introduced in the system of local government in rural Bangladesh following the country's independence. Examination reveals that they were changes only in nomenclature, and did not result in significant improvements. The constant effort by the central government to retain control over local bodies, and the tendency of the ruling elite not to disturb the existing local government system, have worked to the detriment of reforms. The existing local government system failed to satisfy the aspirations of the rural Bangladeshis for increased participation in local affairs. After the first change of government in Bangladesh, the new ruling group felt the need for a support base in the rural areas. The formation of a new political party and the necessity of extending it to the grass roots, increased the desire of the people to participate in local affairs, and the realization of the importance of initiating and completing rural development programmes at the lowest level made the government aware of the need for local government institutions based in the villages. The government was impressed by the success of the Swanirvar Bangladesh Andolon, and introduced Swanirvar Gram Sarkar as a major reform in the local government system.
Cooperative education and training at the grassroots in Nigeria
Authors: Okbreke O. , Mereni J. I.
Published: July 2007

Faced with evidence of an appallingly low standard of living which the vast majority of men and women in Nigeria have despite two decades of development and cooperative movements, the Federal and State Governments now attempt to ensure that the real target of development are the human beings who will remain central to all redefinitions and to all revised strategies. This study proposes a theoretical framework for cooperative education and training programmes in the rural areas of Nigeria in order to raise the level of understanding and performance of cooperative members. The approach is primarily an amalgam of the general process model of organization systems and McGrath's problem ‐ based/problem ‐ solving systems. Application of the approach subsequently suggests a method of scientific inquiry which this paper conceives as the Cooperative Education Working Model. To be most effective, Nigerian cooperators must regard cooperative education and training as a vital benefit which their membership provides for them.
Problems of implementation
Authors: Bowden Peter
Published: July 2007

The paper examines a number of empirical studies which investigate the implementation problems that have been experienced in Third World countries. Most of these studies are evaluation studies, specifically undertaken in order to identify the type and frequency with which implementation problems were being experienced. Only one of the studies is country‐specific (Indonesia), drawing its data directly from the problem‐reporting component of the national monitoring system, although encompassing a sufficiently large number of projects for some general conclusions to be drawn. The paper finds that about half of the implementation difficulties experienced in Third World projects or programmes arise through the procedures and operating methods of central ministries other than the implementing ministry. The key ministries are principally planning, finance and personnel. Concentration by Third World governments on strengthening the central procedures under which all projects operate, therefore, is likely to have a disproportionately high impact on the implementation of development programmes. Suggestions for obtaining this improvement conclude the paper.
Planning and conducting federally funded scientific research in Nigeria
Authors: Schweitzer Glenn E.
Published: July 2007

During the past two decades Nigeria has invested heavily in scientific research, by developing country standards. Yet these investments at best have had only marginal impacts on the activities of the production and service sectors even though there are many priority development activities which could benefit from inputs from Nigerian researchers. At the national level efforts to direct or even co‐ordinate the planning and budgeting of research have been seriously hampered by frequent changes in organizational responsibilities and by repeated budget cuts. Historically, the activities of the federal research institutes have been poorly tuned to the interests and capabilities of the potential users of their research products. Neither these institutes nor the universities with research activities are in a position to develop products or processes which can compete with imported technologies that are saturating the economy. However, the research institutes, and to a lesser extent the universities, should make greater contributions in applying science to improved use of the nation's natural resource endowments, although significant changes in research management at the project level are needed if this objective is to be realized. The Government should provide incentives to the multinational companies operating in Nigeria to develop joint programmes with the research institutes and universities as one mechanism for diffusing the administrative and technical capabilities of the companies. Meanwhile, selected public sector enterprises should be encouraged to expand technological innovation efforts which could be directly applied to their production activities.
Urban community organizations and local government: Exploring relationships and roles
Authors: White Louise G.
Published: July 2007

There is an increasing interest in using local community organizations to assist in the development process. Observers who evaluate the contribution of such groups frequently classify them into two clusters: those which are closely tied to the government and focus on service delivery, and those which guard their autonomy and engage in development rather than service delivery. This dichotomy, however, downplays the developmental role of groups allied with local governments and obscures some important contributions they can offer. Three different models are proposed and two case studies of service‐oriented groups in Cairo are presented. The cases suggest that an important criterion in assessing voluntary groups is the extent to which their service delivery role enables them to develop an organization. From this perspective their role is potentially much broader than expediting government services.