bluuebunny/crossref_metadata_2025 huggingface dataset:
New molecular markers of early and progressive CJD brain infection
Authors: Lu Zhi Yun , Baker Christopher A. , Manuelidis Laura
Published: August 2004

Transmissible spongiform encephalopathies (TSEs), including human Creutzfeldt–Jakob disease (CJD), are caused by a related group of infectious agents that can be transmitted to many mammalian species. Because the infectious component of TSE agents has not been identified, we examined myeloid cell linked inflammatory pathways to find if they were activated early in CJD infection. We here identify a specific set of transcripts in CJD infected mouse brains that define early and later stages of progressive disease. Serum amyloid A3 and L‐selectin mRNAs were elevated as early as 20 days after intracerebral inoculation. Transcripts of myeloid cell recruitment factors such as MIP‐1α, MIP‐1β, and MCP1, as well as IL1α and TNFα were upregulated >10 fold between 30 and 40 days, well before prion protein (PrP) abnormalities that begin only after 80 days. At later stages of symptomatic neurodegenerative disease (100–110 days), a selected set of transcripts rose by as much as 100 fold. In contrast, normal brain inoculated controls showed no similar sequential changes. In sum, rapid and simple PCR tests defined progressive stages of CJD brain infection. These markers may also facilitate early diagnosis of CJD in accessible peripheral tissues such as spleen and blood. Because some TSE strains can differentially target particular cell types such as microglia, several of these molecular changes may also distinguish specific agent strains. The many host responses to the CJD agent challenge the assumption that the immune system does not recognize TSE infections because these agents are composed only of the host's own PrP. © 2004 Wiley‐Liss, Inc.
Proteomic analyzes of copper metabolism in an in vitro model of Wilson disease using surface enhanced laser desorption/ionization‐time of flight‐mass spectrometry
Authors: Roelofsen Han , Balgobind Reshma , Vonk Roel J.
Published: August 2004

In Wilson disease, mutations in theATP7B‐gene lead to hepatic accumulation of copper that becomes toxic when the hepatic binding capacity is exceeded, leading to oxidative stress and acute liver failure. Several proteins are probably involved in dealing with the excess copper and oxidative stress. As a first step towards biomarker discovery and analyzes of copper metabolism in Wilson disease patients we characterized copper‐induced changes in protein expression in cell lysates and culture media from an in vitro copper‐overload model using surface enhanced laser desorption/ionization (SELDI) proteomics technology. HepG2 cells were cultured for 48 h with a physiological (0.5 μM) or a pathological (100 μM) copper concentration. Samples were applied to weak cation exchange (WCX) proteinchip® arrays and chips were analyzed by time of flight (TOF)‐mass spectrometry. Copper‐coated IMAC chips were used to detect copper‐binding proteins in cell lysate of copper depleted cells using buffers with increasing imidazole concentrations. Data from the 2 to 50 kDa range indicate that high extra‐cellular copper substantially altered both intra‐cellular protein expression as well as the composition of the secretome. In the lysate 15 proteins were found up‐regulated, while 6 proteins were down‐regulated. In culture media 21 proteins were increased while 4 proteins were decreased in abundance. Copper‐coated protein chips revealed the presence of 18 high‐affinity copper‐binding proteins. Further identification is necessary to determine the exact cellular roles of the discovered proteins. © 2004 Wiley‐Liss, Inc.
Prostate specific antigen gene regulation by androgen receptor
Authors: Kim Joshua , Coetzee Gerhard A.
Published: August 2004

Prostate specific antigen (PSA) is a serine protease that is synthesized by both normal and malignant epithelial cells of the human prostate. PSA expressed by malignant cells, however, are released into the serum at an increased level, which can be detected to diagnose and monitor prostate cancer. Moreover, increases in serum PSA following local and systemic treatments are highly correlated with tumor recurrence and progression, and this association has further established PSA as a clinically important biomarker. The expression of PSA is mainly induced by androgens and regulated by the androgen receptor (AR) at the transcriptional level. Extensive research on the regulation of PSA gene expression has provided significant information about the function of AR, which is a crucial transcription factor involved in all phases of prostate cancer. Still, the molecular mechanism(s) by which the transcription of the PSA gene escapes regulation in advanced prostate cancer has yet to be clearly defined. Accumulating evidence suggests that a number of processes including androgen‐independent activation of AR are involved. Lacking an effective treatment, advanced prostate cancer is almost invariably fatal, which highlights the importance of elucidating mechanisms of tumor progression. Insights into AR activity at the PSA gene could be extended to transcriptional regulation of other AR target genes, which may be crucial in discerning prostate cancer progression. Ultimately, our improved understanding of AR‐regulated PSA expression could aid in developing viable therapies in treating and/or preventing advanced prostate cancer. © 2004 Wiley‐Liss, Inc.
Modeled microgravity disrupts collagen I/integrin signaling during osteoblastic differentiation of human mesenchymal stem cells
Authors: Meyers Valerie E. , Zayzafoon Majd , Gonda Steve R. , Gathings William E. , McDonald Jay M.
Published: August 2004

Spaceflight leads to reduced bone mineral density in weight bearing bones that is primarily attributed to a reduction in bone formation. We have previously demonstrated severely reduced osteoblastogenesis of human mesenchymal stem cells (hMSC) following 7 days culture in modeled microgravity (MMG). One potential mechanism for reduced osteoblastic differentiation is disruption of type I collagen (Col I)–integrin interactions and reduced integrin signaling. Integrins are heterodimeric transmembrane receptors that bind extracellular matrix (ECM) proteins and produce signals essential for proper cellular function, survival, and differentiation. Therefore, we investigated the effects of MMG on integrin expression and function in hMSC. We demonstrate that 7 days of culture in MMG leads to reduced expression of the ECM protein, Col I. Conversely, MMG consistently increases Col I‐specific α2 and β1 integrin protein expression. Despite this increase in integrin subunit expression, autophosphorylation of adhesion‐dependent kinases, focal adhesion kinase (FAK) and proline‐rich tyrosine kinase 2 (PYK2), is significantly reduced. Activation of Akt protein kinase (Akt) is unaffected by the reduction in FAK activation. However, reduced downstream signaling via the Ras‐mitogen activated protein kinase (MAPK) pathway is evidenced by a reduction in Ras and extracellular signal‐related protein kinase (ERK) activation. Taken together, our findings indicate that MMG decreases integrin/MAPK signaling, which likely contributes to the observed reduction in osteoblastogenesis. © 2004 Wiley‐Liss, Inc.
Abnormal cell cycle regulation in primary human uveal melanoma cultures
Authors: Pardo María , Piñeiro Antonio , de la Fuente María , García Angel , Prabhakar Sripadi , Zitzmann Nicole , Dwek Raymond A. , Sánchez‐Salorio Manuel , Domínguez Fernando , Capeans Carmen
Published: August 2004

Uveal malignant melanoma is the most frequent primary intraocular tumor in adult humans. The cellular events leading to neoplasic transformation of normal uveal melanocytes are not well known when compared to other cancers. In this study, we investigated the role of G1 and G1/S regulatory proteins of the cell cycle in human uveal melanoma (UM) primary cell cultures, since these proteins are common targets in tumor development. Further, freshly established and characterized tumor cells are a better model for in vitro studies when compared to cell lines established long ago. Human primary cell cultures from eight different UM were established, as well as one primary culture from rhesus uveal normal melanocytes (UNM). Primary human UM cultures were characterized by a low establishment and growing rate. From four successful cultures, three showed a high expression of cyclin D1, cyclin E, p16INK4A, and p27KIP1 with no variations in cyclin A, cyclin‐dependent kinase 2 (CDK2), and CDK4. Interestingly, in one of the cultured tumors, tumor suppressor protein retinoblastoma (Rb) did not bind E2F despite the fact that Rb was found in its hypophosphorylated form. No mutations in either RB1 or the Rb‐binding pocket of E2F‐1 were detected. Furthermore, we identified seven proteins co‐immunoprecipitating with Rb in this tumor, including Lamin A/C and six proteins not previously reported to bind Rb: Hsc70, high mobility group protein 1 (HMG‐1), hnRPN, glyceraldehyde 3 phosphate dehydrogenase (G3PDH), EF‐1, and EF‐2. Our results indicate that the overexpression of cyclins D1/E and CDKIs p16 and p27, together with a deregulation of the Rb/E2F pathway, may be implicated in the development of human UM. © 2004 Wiley‐Liss, Inc.
Dominant‐negative CREB inhibits heparanase functionality and melanoma cell invasion
Authors: Aucoin Rebecca , Reiland Jane , Roy Madhuchhanda , Marchetti Dario
Published: August 2004

Heparanase (HPSE‐1) is an endo‐β‐d‐glucuronidase involved in the degradation of cell‐surface/extracellular matrix heparan sulfate (HS) in normal and neoplastic tissues. HPSE‐1 represents the first example of purification and cloning of a mammalian HS‐degradative enzyme. Elevated HPSE‐1 levels are known to be associated with metastatic cancers, directly implicating HPSE‐1 in metastatic events. The purpose of this study was to determine the role of cAMP response element‐binding protein (CREB) in modulating HPSE‐1‐mediated effects on human melanoma cell invasion. Highly invasive, brain‐metastatic melanoma cells (70W) were transfected with the dominant‐negative CREB (KCREB) and subsequently analyzed for changes in their HPSE‐1 content, functionality, and cell invasive properties. KCREB‐transfected cells showed a decrease in HPSE‐1 mRNA expression and activity. This correlated with a significantly decreased invasion of these cells through Matrigel™‐coated filters. Furthermore, adenoviral vectors containing the full‐length human HPSE‐1 cDNA in sense orientation (Ad‐S/hep) were constructed to investigate CREB effects on HPSE‐1. Restoration of HPSE‐1 expression and functionality following Ad‐S/hep infection of KCREB‐transfected 70W cells recovered melanoma cell invasiveness. These results demonstrate that KCREB inhibits HPSE‐1 and suggest that one of the roles CREB plays in the acquisition of melanoma cells metastatic phenotype is affecting HPSE‐1 activity. © 2004 Wiley‐Liss, Inc.
Cytoskeletal organization of human mesenchymal stem cells (MSC) changes during their osteogenic differentiation
Authors: Pablo Rodríguez J. , González Mauricio , Ríos Susana , Cambiazo Verónica
Published: August 2004

Human MSCs have been studied to define the mechanisms involved in normal bone remodeling and the regulation of osteogenesis. During osteogenic differentiation, MSCs change from their characteristic fibroblast‐like phenotype to near spherical shape. In this study, we analyzed the correlation between the organization of cytoskeleton of MSCs, changes in cell morphology, and the expression of specific markers (alkaline phosphatase activity and calcium deposition) of osteogenic differentiation. For osteoblastic differentiation, cells were cultured in a culture medium supplemented with 100 nM dexamethasone, 10 mM β‐ glycerophosphate, and 50 μg/ml ascorbic acid. The organization of microfilaments and microtubules was examined by inmunofluorescence using Alexa fluor 594 phalloidin and anti α‐tubulin monoclonal antibody. Cytochalasin D and nocodazole were used to alter reversibly the cytoskeleton dynamic. A remarkable change in cytoskeleton organization was observed in human MSCs during osteogenic differentiation. Actin cytoskeleton changed from a large number of thin, parallel microfilament bundles extending across the entire cytoplasm in undifferentiated MSCs to a few thick actin filament bundles located at the outermost periphery in differentiated cells. Under osteogenic culture conditions, a reversible reorganization of microfilaments induced by an initial treatment with cytochalasin D but not with nocodazole reduced the expression of differentiation markers, without affecting the final morphology of the cells. The results indicate that changes in the assembly and disassembly kinetics of microfilaments dynamic of actin network formation may be critical in supporting the osteogenic differentiation of human MSCs; also indicated that the organization of microtubules appears to have a regulatory role on the kinetic of this process. © 2004 Wiley‐Liss, Inc.
PM3‐compatible zinc parameters optimized for metalloenzyme active sites
Authors: Brothers Edward N. , Suarez Dimas , Deerfield David W. , Merz Kenneth M.
Published: August 2004

Recent studies have shown that semiempirical methods (e.g., PM3 and AM1) for zinc‐containing compounds are unreliable for modeling structures containing zinc ions with ligand environments similar to those observed in zinc metalloenzymes. To correct these deficiencies a reparameterization of zinc at the PM3 level was undertaken. In this effort we included frequency corrected B3LYP/6‐311G* zinc metalloenzyme ligand environments along with previously utilized experimental data. Average errors for the heats of formation have been reduced from 46.9 kcal/mol (PM3) to 14.2 kcal/mol for this new parameter set, termed ZnB for “Zinc, Biological.” In addition, the new parameter sets predict geometries for the Bacillus fragilis active site model and other zinc metalloenzyme mimics that are qualitatively in agreement with high‐level ab initio results, something existing parameter sets failed to do. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1677–1692, 2004
Solvation effects on alanine dipeptide: A MP2/cc‐pVTZ//MP2/6‐31G** study of (Φ, Ψ) energy maps and conformers in the gas phase, ether, and water
Authors: Wang Zhi‐Xiang , Duan Yong
Published: August 2004

The effects of solvation on the conformations and energies of alanine dipeptide (AD) have been studied by ab initio calculations up to MP2/cc‐pVTZ//MP2/6‐31G**, utilizing the polarizable continuum model (PCM) to mimic solvation effects. The energy surfaces in the gas phase, ether, and water bear similar topological features carved by the steric hindrance, but the details differ significantly due to the solvent effects. The gas‐phase energy map is qualitatively consistent with the Ramachandran plot showing seven energy minima. With respect to the gas‐phase map, the significant changes of the aqueous map include (1) the expanded low‐energy regions, (2) the emergence of an energy barrier between C5‐β and αR‐β2 regions, (3) a clearly pronounced αR minimum, a new β‐conformer, and the disappearance of the gas‐phase global minimum, and (4) the shift of the dominant region in LEII from the gas‐phase C7ax region to the αL region. These changes bring the map in water to be much closer to the Ramachandran plot than the gas‐phase map. The solvent effects on the geometries include the elongation of the exposed NH and CO bonds, the shortening of the buried HNCO peptide bonds, and the enhanced planarity of the peptide bonds. The energy surface in ether has features similar to those both in the gas phase and in water. The free energy order computed in the gas phase and in ether is in good agreement with experimental studies that concluded that C5 and C7eq are the dominant species in both the gas phase and nonpolar solvents. The free energy order in water is consistent with the experimental observation that the dominant C7eq in the nonpolar solvent was largely replaced by PII‐like (i.e., β) and αR in the strong polar solvents. Based on calculations on AD + 4H2O and other AD–water clusters, we suggest that explicit water–AD interactions may distort C5 and β (or αR and β) to an intermediate conformation. Our analysis also shows that the PCM calculations at the MP2/cc‐pVTZ//MP2/6‐31G** level give good descriptions to the bulk solvent polarization effect. The results presented in this article should be of sufficient quality to characterize the peptide bonds in the gas phase and solvents. The energy surfaces may serve as the basis for developing of strategies enabling the inclusion of solvent polarization in the force field. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1699–1716, 2004
Hybridized particle swarm algorithm for adaptive structure training of multilayer feed‐forward neural network: QSAR studies of bioactivity of organic compounds
Authors: Shen Qi , Jiang Jian‐Hui , Jiao Chen‐Xu , Lin Wei‐Qi , Shen Guo‐Li , Yu Ru‐Qin
Published: August 2004

The multilayer feed‐forward ANN is an important modeling technique used in QSAR studying. The training of ANN is usually carried out only to optimize the weights of the neural network and without paying attention to the network topology. Some other strategies used to train ANN are, first, to discover an optimum structure of the network, and then to find weights for an already defined structure. These methods tend to converge to local optima, and may also lead to overfitting. In this article, a hybridized particle swarm optimization (PSO) approach was applied to the neural network structure training (HPSONN). The continuous version of PSO was used for the weight training of ANN, and the modified discrete PSO was applied to find appropriate the network architecture. The network structure and connectivity are trained simultaneously. The two versions of PSO can jointly search the global optimal ANN architecture and weights. A new objective function is formulated to determine the appropriate network architecture and optimum value of the weights. The proposed HPSONN algorithm was used to predict carcinogenic potency of aromatic amines and biological activity of a series of distamycin and distamycin‐like derivatives. The results were compared to those obtained by PSO and GA training in which the network architecture was kept fixed. The comparison demonstrated that the HPSONN is a useful tool for training ANN, which converges quickly towards the optimal position, and can avoid overfitting in some extent. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1726–1735, 2004
A dynamic lattice searching method for fast optimization of Lennard–Jones clusters
Authors: Shao Xueguang , Cheng Longjiu , Cai Wensheng
Published: August 2004

A highly efficient unbiased global optimization method called dynamic lattice searching (DLS) was proposed. The method starts with a randomly generated local minimum, and finds better solution by a circulation of construction and searching of the dynamic lattice (DL) until the better solution approaches the best solution. The DL is constructed adaptively based on the starting local minimum by searching the possible location sites for an added atom, and the DL searching is implemented by iteratively moving the atom located at the occupied lattice site with the highest energy to the vacant lattice site with the lowest energy. Because the DL can greatly reduce the searching space and the number of the time‐consuming local minimization procedures, the proposed DLS method runs at a very high efficiency, especially for the clusters of larger size. The performance of the DLS is investigated in the optimization of Lennard–Jones (LJ) clusters up to 309 atoms, and the structure of the LJ500 is also predicted. Furthermore, the idea of dynamic lattice can be easily adopted in the optimization of other molecular or atomic clusters. It may be a promising approach to be universally used for structural optimizations in the chemistry field. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1693–1698, 2004
Dexamethasone regulation of cFos mRNA in osteoprogenitors
Authors: Shur Irena , Socher Rina , Benayahu Dafna
Published: August 2004

The glucocorticoid, dexamethasone (Dex), has a beneficial effect on osteogenesis by increasing the activation and differentiation of osteoblastic cells. We investigated the effect of Dex on osteoblasts and detected changes in pattern of expression of cFos mRNA. cFos is an early response gene that is expressed as unspliced and spliced mRNAs. We analyzed the regulation of cFos mRNA in correlation with the cell proliferation status and following the induction by Dex. Treatment of osteoblastic cells with Dex for 30 min resulted in elevated levels of spliced form of cFos mRNA, which was maintained with extended treatment of cultured cells for 24 h. In addition, we demonstrated interaction between glucocorticoid receptor (GR) and cFos mRNA. This study provides evidence for the action of Dex on osteoblasts through dynamic cell responses involving with cFos. © 2005 Wiley‐Liss, Inc.
14‐3‐3 regulation of cell spreading and migration requires a functional amphipathic groove
Authors: Rodriguez Luis G. , Guan Jun‐Lin
Published: August 2004

The 14‐3‐3 proteins associate with many cellular proteins that participate in the regulation of various cellular events including apoptosis, the cell cycle, spreading, and migration. We have previously described that 14‐3‐3β binds the β1‐integrin and overexpression of 14‐3‐3β promoted increased cell spreading and migration (Han et al. [2001] Oncogene 20: 346–357). In this study, we find that mutation of Ser 60 of 14‐3‐3β, outside of the amphipathic groove which is involved in 14‐3‐3 protein interactions with other ligands, abolished its interaction with integrin. Surprisingly, this mutant retained its ability to promote cell spreading, suggesting that 14‐3‐3β interaction with the β1‐integrin is not required for its regulation of cell adhesion. We next showed that mutations of several critical residues in the amphipathic groove did not affect 14‐3‐3β interaction with the β1‐integrin. As expected, these mutants disrupted their association with the phosphoserine dependent ligands Raf and Cas. Analysis of the groove mutant LF (mutation of Arg129Tyr130 to Leu and Phe) indicated that, unlike wild type 14‐3‐3β, it could not stimulate cell spreading or migration, suggesting that a functional amphipathic groove is required for 14‐3‐3 regulation of cell adhesion and migration. Consistent with this, cells expressing the LF mutant exhibited a delay in F‐actin organization compared to cells expressing wild type or the S60A mutant (Ser 60 to Ala mutation) upon cell adhesion to fibronectin (FN). Taken together, these studies identified a novel binding site on 14‐3‐3 for integrin β1 and showed that a functional amphipathic groove, rather than its interaction with integrin β1, is required for 14‐3‐3 regulation of cell spreading and migration. © 2005 Wiley‐Liss, Inc.
Ortho‐selective vapour phase methylation of phenol over nanocrystalline ferrospinels of varying Zn2+/Mn2+ ionic composition
Authors: Reddy Vanga S , Shyam A Radhe , Dwivedi R , Gupta RK , Chumbale VR , Prasad R
Published: August 2004

Ortho‐selective vapour phase methylation of phenol with methanol has been carried out over Zn(1−x)MnxFe2O4 (x = 0, 0.25, 0.5, 0.75, 1.0) in the temperature range 423–698K in a fixed‐bed, down‐flow reactor. o‐Cresol and 2,6‐xylenol were found to be the major products. Reaction parameters were optimized over MnFe2O4 (MF). Maximum yields of 68.3% and 14% with selectivities of 81% and 17% were obtained for 2,6‐xylenol and o‐cresol respectively, giving a total selectivity of 98% over MnFe2O4 at 598K, methanol to phenol molar ratio 6, and 0.4 h−1 weight hour space velocity. It was found that the product selectivity is greatly influenced by the acido‐basic properties of the catalysts. o‐Cresol formation is favoured over catalysts with weak acid sites whereas formation of 2,6‐xylenol occurs in the presence of stronger acid sites. Catalyst characterization has been carried out by X‐ray diffraction, infrared spectroscopy and ammonia desorption methods. X‐ray diffractograms were used to determine the unit cell length and correlated with the acidity and catalytic activity of the spinel systems. IR absorption bands observed around 700 cm−1 and 500 cm−1 are respectively attributed to the tetrahedral and octahedral metal‐oxygen stretching mode of the spinel. Shifting of bands towards lower wave numbers is correlated with composition and acidity of the spinel systems. The results are discussed on the basis of the Zn2+ and Mn2+ composition and acidity of the spinel systems. Copyright © 2004 Society of Chemical Industry
Positioning the non‐least‐developed developing countries based on vulnerability‐related indicators
Authors: Liou Fen‐May , Ding Cherng G.
Published: August 2004

A structure presenting relevant constructs of vulnerability for developing but not least‐developed countries in the global trade regime shift was first proposed. Based on the structure, the vulnerability constructs were empirically summarized as three independent factors: economic scale, volatility degree, and development level. A map, showing the overall vulnerability positioning of the countries, with dimensions of ‘economic scale’ and ‘volatility with resilience of development’, was further created. The map reveals that most small‐population states are more vulnerable. Nevertheless, some large economies may not be less vulnerable and should not be excluded if special treatments are offered to non‐least‐developed small states. Copyright © 2004 John Wiley & Sons, Ltd.
Tax performance: a comparative study
Authors: Teera Joweria M. , Hudson John
Published: August 2004

This paper seeks to analyse tax performance across countries, utilizing what Musgrave (1969) referred to as the stochastic approach, where tax performance is analysed by comparisons with the average performance. The regression approach to tax performance assessment is used and a tax effort index is constructed. Among the variables that are identified to be important determinants of tax shares is a measure of tax evasion. The tax effort indices obtained show that generally the upper middle‐income and high‐income OECD groups are making better use of their tax bases to increase revenue. There are also economies of scale with respect to population density. Copyright © 2004 John Wiley & Sons, Ltd.
What is the enabling state? The views of textiles and garments entrepreneurs in Zimbabwe
Authors: Jackson Paul
Published: August 2004

This paper summarizes the approach and findings of a piece of research sponsored by the Department for International Development (DFID) in the UK and carried out in 1998 and 1999 mainly in Harare and Bulawayo. The primary aim of the work was to contribute to an improvement in facilitating an enabling environment for the private sector in Zimbabwe. It aimed to achieve this objective by developing and testing a participative methodology based on the use of historical profiles, checklists, Venn diagrams, master charts, workshops and other participative methodologies. These processes were introduced and developed with a group of 40 entrepreneurs and managers and several representatives from trade unions, government, and agencies. The design aimed to allow participants to express their own agendas, ideas and approaches instead of reacting to a more rigid approach reflecting the agendas of the research team.

The research team adopted a broad structure based around three main areas affecting firms: the policy, agency and firm environments. The use of semi‐structured interviews and workshops allowed a detailed exploration of these issues and produced a comprehensive list of problems identified and proposed solutions. The importance of the research is in its ability to construct a firm level, rather than government or donor level view of the enabling environment. Copyright © 2004 John Wiley & Sons, Ltd.
Explaining corruption: are open countries less corrupt?
Authors: Gatti Roberta
Published: August 2004

This paper analyses whether the presence of barriers to international trade and capital flows is associated with higher corruption. The evidence suggests that the main impact of trade barriers on corruption comes through the incentive to collusive behaviors between individuals and customs officials, rather than from the decreased foreign competition pressure on the domestic sector induced by restrictive trade policy. Interestingly, no clear association emerges between corruption and variables proxying for presence and intensity of controls on capital flows. Copyright © 2004 John Wiley & Sons, Ltd.
An empirical study of the determinants of self‐employment in developing countries
Authors: Pietrobelli Carlo , Rabellotti Roberta , Aquilina Matteo
Published: August 2004

Official statistics record a tremendous diversity in the level and dynamics of the self‐employment rate across countries. Such diversity is even more pronounced for developing countries than for industrial countries. In these countries, self‐employment figures may represent evidence of the spark of an emerging entrepreneurial class still in its infant stages, or conceal marginal urban manufacturing employment at the mere level of subsistence and disguising actual unemployment in years of economic depression. This paper documents this diversity for developing and developed countries with new empirical evidence, and tests the determinants of this diversity with econometric techniques. Estimates are presented on a sample of 64 developing countries and 19 developed countries in a period from the 1960s through the 1990s.

The results generally confirm a negative association between the rate of self‐employment and the stage of development: self‐employment would tend to disappear with the development process. However, we present evidence suggesting that in some cases self‐employment is also related to high value‐added manufactured exports, representing a dynamic and emerging form of entrepreneurship. To this aim, self‐employment would not be motivated by the desire to evade taxes, but rather an active role of the government may enhance it. The relationships with the development of the financial sector, educational levels, and other cultural factors tend to vary. Copyright © 2004 John Wiley & Sons, Ltd.
The effects of policy, institutions and geography on economic growth in Africa: an econometric study based on cross‐section and panel data
Authors: Naudé W. A.
Published: August 2004

This paper use both single period cross‐section data as well as panel data for the period 1970 to 1990 (largely obtained from version 6.1 of the Penn World Tables) to identify the determinants of Africa's growth in per capita GDP, as well as to evaluate the empirical relevance of recent contributions that stresses the potential importance of geographical vs institutional factors in Africa's growth. The paper further contributes by making use of recent cross‐country data on institutional quality and geographical characteristics of African countries. To address the danger of using an inappropriate estimation method, a number of estimation methods was used, namely OLS, LAD, GLS‐random effects, fixed effects as well as a dynamic GMM‐estimator. The results confirmed that the more efficient and dynamic GMM‐estimator is superior and that controlling for unobserved heterogeneity, dynamic effects and endogeneity of the regressors is important. It is concluded that there is conditional convergence in Africa, and that literacy, investment, FDI and urban agglomeration have a significant positive effect on GDP per capita growth in Africa. Growth is negatively affected by government expenditure, settler mortality, malaria, landlockedness and landarea. These results support Acemoglu et al.'s (2001) ‘reversal of fortune’ thesis, namely that settler mortality is inversely related to economic growth. It further suggests that it is not one of either institutions or geography that are more important than the other, but rather that geography may have an important impact on institutions. The robust finding that the incidence of malaria has a particularly large impact on economic growth in Africa supports this conclusion. Copyright © 2004 John Wiley & Sons, Ltd.
The International Finance Facility
Authors: Treasury HM
Published: August 2004

In January 2003 HM Treasury and the Department for International Development (DFID) launched a proposal for an International Finance Facility (IFF). The IFF is designed to ‘frontload’ aid to help meet the internationally agreed Millennium Development Goals. Estimates suggest that development assistance must be doubled and focused on the poorest countries if the Millennium Development Goals are to be met—an increase of at least $50 billion a year.1 At the UN's International Conference on Financing in Monterrey in 2002, donors pledged to provide an additional $16 billion a year from 2006. But this means a significant resource gap must be bridged if the Millennium Development Goals are to be reached. The Millennium Development Goals represent different indicators of the same basic poverty. Investments in different sectors must take place simultaneously to ensure sustainable progress. Education, health, access to water, roads and other infrastructure for growth must be tackled at the same time to ensure a lasting exit from poverty. Funding for debt relief should reinforce, not replace, funding to build a skilled work force and the infrastructure and capacity to trade. The IFF, as a stable financing vehicle, could provide the critical mass of additional and predictable funding needed to make lasting progress in all these areas. Donors are committed to reaching the target of 0.7 per cent ODA/GNI, but a number have fiscal constraints that will not allow them to increase aid levels in the short to medium term. The IFF should be seen as a complement to donors' long‐term commitment to 0.7 per cent ODA/GNI: it would meet the immediate need for resources to meet the MDGs as donors move towards the 0.7 per cent ODA/GNI target. © Crown Copyright 2004. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Avoiding the elephant traps: a commentary on the International Finance Facility
Authors: Mosley Paul
Published: August 2004

This commentary welcomes the ambitious vision underlying the IFF and suggests ways of avoiding four ‘elephant traps’ to which it is vulnerable; neglect of the poor in middle‐income countries, absorptive capacity, fungibility and knock‐on effects on interest rates. Absorptive capacity would appear the biggest of these hazards, but to some extent it can be got round, and is being, through imaginative use of ‘new conditionality.’ Copyright © 2004 John Wiley & Sons, Ltd.
The International Finance Facility—reaching the MDGS without spending more?
Authors: Moore Karen , Hulme David
Published: August 2004

This paper comprises a brief review of current debates around the potential benefits and drawbacks of the proposed International Finance Facility (IFF). The IFF's main strength is clear: it recognizes the urgent need for significantly larger and more predictable aid flows, and suggests a financial mechanism able to deliver such flows within existing political constraints. However, several aspects of the proposal have the potential to exacerbate current aid ineffectiveness and inequality in both the short and longer term. These factors include the IFF's governance structure; the ‘extra layer’ of conditionality added by the IFF; the potential sharp decline in aid flows after the IFF's initial phase; and the detraction of attention from other important global agendas. More work on developing innovative mechanisms to deliver social protection and basic services to poorly‐governed or conflict‐ridden areas is required, as are more courageous actions on the part of the UK and other rich countries. Otherwise, the IFF could mean mortgaging the future well‐being of 900 million hard‐to‐reach poor people in order to achieve—or come closer to achieving—the MDGs today. Copyright © 2004 John Wiley & Sons, Ltd.
Joseph Stiglitz's, Globalization and its Discontents
Authors: Perraton Jonathan
Published: August 2004

Joseph Stiglitz's Globalization and its Discontents has sparked a major critical response since its publication in that it appears to encapsulate widespread doubts about globalization processes and their governance. This review aims to probe further Stiglitz's general analysis and policy prescriptions. It is argued that Stiglitz's central concern is how globalization as currently practised acts to exacerbate existing market failures and produce new ones, and the appropriate response of international economic institutions to address the resulting global collective action problems and ensure that the potential gains from globalization are realized. Whilst many of his proposals remain vague, they can be seen as part of an emerging global social democratic agenda. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of [1‐11C]ethyl iodide from [11C]carbon monoxide and its application in alkylation reactions
Authors: Eriksson Jonas , Antoni Gunnar , Långström Bengt
Published: August 2004

A method is presented for preparing [1‐11C]ethyl iodide from [11C]carbon monoxide. The method utilizes methyl iodide and [11C]carbon monoxide in a palladium‐mediated carbonylation reaction to form a mixture of [1‐11C]acetic acid and [1‐11C]methyl acetate. The acetates are reduced to [1‐11C]ethanol and subsequently converted to [1‐11C]ethyl iodide. The synthesis time was 20 min and the decay‐corrected radiochemical yield of [1‐11C]ethyl iodide was 55 ± 5%. The position of the label was confirmed by 13C‐labelling and 13C‐NMR analysis. [1‐11C]Ethyl iodide was used in two model reactions, an O‐alkylation and an N‐alkylation. Starting with approximately 2.5 GBq of [11C]carbon monoxide, the isolated decay‐corrected radiochemical yields for the ester and the amine derivatives were 45 ± 0.5% and 25 ± 2%, respectively, based on [11C]carbon monoxide. Starting with 10 GBq of [11C]carbon monoxide, 0.55 GBq of the labelled ester was isolated within 40 min with a specific radioactivity of 36 GBq/µmol. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of triple [14C]‐labeled moxonidine
Authors: Czeskis Boris A.
Published: August 2004

The synthesis of radiolabeled antihypertensive compound [2,4,6‐14C3]‐4‐chloro‐5‐(imidazolidin‐2‐ylidenimino)‐6‐methoxy‐2‐methylpyrimidine ([14C3]moxonidine) was accomplished based on condensation of [1‐14C]acetamidine with diethyl [1,3‐14C2]malonate to form [2,4,6‐14C3]‐4,6‐dihydroxy‐2‐methylpyrimidine. Subsequent nitration, chlorination, and hydrogenation gave [2,4,6‐14C3]‐4,6‐dichloro‐2‐methyl‐5‐aminopyrimidine. The final product was obtained after the coupling of the above aminopyrimidine with 1‐acetylimidazolidin‐2‐one, followed by hydrolysis using sodium methoxide. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of N‐[1‐13C]caproyl‐N′‐phenylthiourea
Authors: Simion Corina Anca , Postolache Cristian , Deleanu Calin , Chirtoc Ileana , Barna Catalina Mihaela , Bally Ioana , Balaban Alexandru T.
Published: August 2004

An optimal synthesis of N‐[1‐13C]caproyl‐N′‐phenylthiourea with isotopic enrichment 82% is described, starting from barium [13C]carbonate, using five synthetic steps. Yields were 95% relative to caproyl chloride and 46% relative to barium carbonate. Oxidation of the title compound with manganese dioxide yields the corresponding ureide. Structural similarities with anticonvulsants such as phenacemide make N‐caproyl‐N′‐phenylthiourea an interesting model compound. Copyright © 2004 John Wiley & Sons, Ltd.
Higher‐order finite‐difference schemes with reduced dispersion errors for accurate time‐domain electromagnetic simulations
Authors: Zygiridis Theodoros T. , Tsiboukis Theodoros D.
Published: August 2004

The potential for developing higher‐order finite‐difference time‐domain (FDTD) schemes with reduced phase errors is investigated in the present paper. Using the classic (2,4) FDTD method as the basis of this study, electromagnetic wave propagation is accurately reproduced in the discretized space by replacing isotropic materials with modified, anisotropic in general, ones. The use of such artificial materials improves the simulation's precision significantly around a specific frequency, yet the overall error remains small at a considerably wide bandwidth; therefore, this algorithm can be useful for wideband problems as well. Additionally, it is shown that an even better single‐frequency performance can be attained, when the modified materials are combined with systematically calculated spatial operators. Pursuing a more wideband enhancement of the (2,4) technique, a version realizing more accurate results at almost all frequencies that can be coupled in a staggered grid is derived. Furthermore, novel spatial operators are introduced, with the distinct feature of using extended stencils in more than one directions. It turns out that when such operators are incorporated, a scheme that combines the aforementioned features can be obtained. The theoretical findings of this investigation are verified in a sequence of numerical tests, involving free‐space and guided‐wave propagation, as well as the determination of a cavity's resonant frequencies. Copyright © 2004 John Wiley & Sons, Ltd.
Consistent material operators for tetrahedral grids based on geometrical principles
Authors: Cinalli M. , Edelvik F. , Schuhmann R. , Weiland T.
Published: August 2004

This paper is focused on analysis of the properties of material operators for geometrical methods on tetrahedral grids. The stiffness matrix in electrodynamics, as well as the one in electrostatics, are mathematically proven to be the same for every material operator satisfying a condition which is sufficient for the consistency of the numerical scheme. This gives a new and better insight into the strong similarities existing between the finite element method (FEM) and the finite integration technique (FIT).

A symmetrization of the microcell method, which also ensures the positive definiteness of the material operators, based on geometrical properties of tetrahedra, is proposed. Numerical results in time and frequency domain for resonant cavities are presented and compared to the FEM. Copyright © 2004 John Wiley & Sons, Ltd.
Predictors of length of stay for pediatric liver transplant recipients
Authors: Bucuvalas John C. , Zeng Lan , Anand Ravinder
Published: August 2004

The resources that are directed towards the care of liver transplant recipients are substantial. Approximately 100 million dollars are spent on the hospitalization of the 400-500 children in the United States who undergo liver transplantation each year. Using length of stay as a surrogate marker for hospital resource use, we sought to identify factors that impact length of stay and assess the trends of hospitalization after liver transplantation for a representative population of pediatric liver transplant recipients. The study population was comprised of 956 patients who underwent primary liver transplantation between 1995 and 2003 and survived at least 90 days. Data were retrieved from the Studies of Pediatric Liver Transplantation data registry. The primary outcome was the length of initial hospitalization after liver transplantation. Independent variables were age, gender, race, pediatric end-stage liver disease score (PELD), year of transplantation, organ type, primary disease, length of operation, and insurance status. The mean and standard deviation of length of stay after liver transplantation was 24.0 ± 24.5 days. Multivariate analyses showed that increased hospital stay was associated with infants less than 1 year of age, fulminant liver failure, receiving a technical variant organ from a cadaveric donor, government insurance, and transplant era (before 1999 vs. 1999 or later). Decreasing height z-scores and increasing length of operation were also associated with increased hospital stay. In conclusion, these parameters accounted for only 11% of the total variance, suggesting that post-transplant complications and course account for much of the variability of resource use in the immediate post-transplant period. (Liver Transpl 2004;10:1011-1017.)
Hepatitis C etiology of liver disease is strongly associated with early acute rejection following liver transplantation
Authors: McTaggart Ryan A. , Terrault Norah A. , Vardanian Andrew J. , Bostrom Alan , Feng Sandy
Published: August 2004

Although recurrent hepatitis C (HCV) occurs universally after liver transplantation (LT), its tempo and severity are variable and unpredictable. Diagnosis and treatment of early acute rejection (EAR) likely affect the course of recurrent HCV disease. We have studied a contemporary cohort of LT recipients to reexamine risk factors for EAR. We hypothesized that HCV etiology may represent a significant risk factor for EAR for many reasons. First, recurrent disease commonly causes biochemical abnormalities prompting allograft biopsy. Second, overlapping histologic features of acute rejection and recurrent HCV ambiguity may result in diagnostic ambiguity. Finally, the biology of hepatitis may precipitate an antidonor response in addition to an antiviral response. Records of 285 adult recipients undergoing primary LT for cirrhosis between January 1, 1999, and December 31, 2002, were retrospectively reviewed. EAR was defined as a biopsy-proven or an empirically treated episode within 6 months of LT. Cox proportional hazards analysis identified donor, recipient, transplant, and posttransplant characteristics associated with EAR; Kaplan-Meier analysis was used to assess rejection by etiology. HCV cirrhosis was the etiology for 51% of all LT recipients. There were 135 episodes of EAR (127 biopsy proven) in 117 recipients for an overall incidence of 41%. Patient groups with HCV and cholestatic / autoimmune disease groups exhibited the highest incidence of rejection at 49%. Recipient gender, ethnicity, etiology, LT year, and posttransplant immunosuppression levels were risk factors for EAR in univariate analysis; HCV etiology and female gender remained robust risk factors in multivariate analysis. Interferon-based therapy did not impact the incidence or timing of EAR. In conclusion, HCV etiology is strongly associated with EAR. HCV allograft reinfection may create an immunologic environment predisposed to EAR. Alternatively, the association of HCV and EAR may result from an increased frequency of allograft biopsy and may be further exacerbated by inability to accurately diagnose EAR in the setting of recurrent HCV. (Liver Transpl 2004;10:975-985.)
Novel Method of Producing Polymer Gels in Aqueous Solution Using UV Irradiation
Authors: Ikkai Fumiyoshi , Adachi Eiki
Published: August 2004

Summary: We developed a novel method of producing polymer gels in aqueous solution using UV irradiation. Persulfates were effective photosensitive initiators of polymerization and/or gelation of acryloyl‐type monomers/polymers. The gelation was confirmed by an abrupt increase in light scattering intensity, 〈I(q)〉T, at the gelation point. The gelation method entails significant advantages: it does not need any cross‐linkers, temperature control (heating), and additives except the persulfate.

The UV irradiation time dependence of light scattering intensity, 〈I(q)〉T, for pre‐gel solutions containing N‐isopropylacrylamide (NIPAm) and/or ammonium persulfate (APS).

image

The UV irradiation time dependence of light scattering intensity, 〈I(q)〉T, for pre‐gel solutions containing N‐isopropylacrylamide (NIPAm) and/or ammonium persulfate (APS).