bluuebunny/crossref_metadata_2025_split huggingface dataset:
The biogeochemistry of dissolved nitrogen, phosphorus, and organic carbon along terrestrial‐aquatic flowpaths of a montane headwater catchment in the Peruvian Amazon
Authors: Saunders Thomas J. , McClain Michael E. , Llerena Carlos A. 
Published: July 2006

AbstractDissolved nitrogen (N), phosphorus (P), and organic carbon (C) were sampled along two transects in a first‐order montane tropical (2414 m.a.s.l.) rainforest catchment of the Peruvian Amazon to investigate spatial and temporal controls on nutrient concentrations from uplands to streams. Surface and subsurface waters along transects were sampled during baseflow conditions and following rainfall events from March 2002 to March 2003. During baseflow conditions, we observed strong terrestrial controls on N, P, and dissolved organic carbon (DOC) concentrations in streams. Median NO3− concentrations were relatively constant during both dry and wet seasons in stream water (dry, 0·8 µM; wet, 1·7 µM) compared to upland soil water (dry, 15·5 µM; wet, 32·5 µM) despite significant seasonal fluctuations of NO3− in the upland, riparian, and hyporheic zones. During the dry season, concentrations of dissolved organic N (DON) also decreased markedly between the upland and the stream. Despite this decrease, DON remained the dominant component of total stream water dissolved N. Dissolved organic P (DOP) and soluble reactive P (SRP) concentrations generally followed a spatial trend inverse to that of N. Low median SRP concentrations were recorded during dry and wet seasons in the upland (dry, 0·11 µM; wet, 0·08 µM) while the highest median SRP concentrations were in stream water (dry, 0·22 µM; wet, 0·20 µM). DOP also dominated total dissolved P concentrations from the upland to the stream. Stoichiometric ratios of dissolved N and P contrasted between the upland (DON:DOP = 734, dissolved inorganic N (DIN):SRP = 166; dry season) and the stream (DON:DOP = 3, DIN:SRP = 12; dry season), indicating a clear divergence of nutrient composition between terrestrial and aquatic systems. Under baseflow conditions, strong mechanisms in the terrestrial environment and at the terrestrial–aquatic interface controlled the nutrient concentrations in the stream and buffered the seasonal fluctuations occurring in the terrestrial environment. In contrast, storm flowpaths may short‐circuit baseflow nutrient controls, thereby exporting a pulse of nutrients to the stream. Understanding the influences of storms in headwater catchments will be a valuable next step in determining the effects of changing precipitation regimes on the nutrient status of montane tropical forests and their receiving waters. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of novel genes associated with astrocytoma progression using suppression subtractive hybridization and real‐time reverse transcription‐polymerase chain reaction
Authors: van den Boom Jörg , Wolter Marietta , Blaschke Britta , Knobbe Christiane B. , Reifenberger Guido 
Published: July 2006

AbstractTo identify novel genes involved in glioma progression we performed suppression subtractive hybridization combined with cDNA array analysis on 4 patients with primary low‐grade gliomas of World Health Organization (WHO) grade II that recurred as secondary glioblastomas (WHO grade IV). Eight genes showing differential expression between primary and recurrent tumors in 3 of the 4 patients were selected for further analysis using real‐time reverse transcription‐PCR on a series of 10 pairs of primary low‐grade and recurrent high‐grade gliomas as well as 42 astrocytic gliomas of different WHO grades. These analyses revealed that 5 genes, i.e., AMOG (ATP1B2, 17p13.1), APOD (3q26.2‐qter), DMXL1 (5q23.1) DRR1 (TU3A, 3p14.2) and PSD3 (KIAA09428/HCA67/EFA6R, 8p22), were expressed at significantly lower levels in secondary glioblastomas as compared to diffuse astrocytomas of WHO grade II. In addition, AMOG, DRR1 and PSD3 transcript levels were significantly lower in primary glioblastomas than in diffuse astrocytomas. Treatment of glioma cell lines with 5‐aza‐2′‐deoxycytidine and trichostatin A resulted in increased expression of AMOG and APOD transcripts. Sequencing of sodium bisulfite‐modified DNA demonstrated AMOG promoter hypermethylation in the glioma cell lines and 1 primary anaplastic astrocytoma with low AMOG expression. Taken together, we identified interesting novel candidate genes that likely contribute to glioma progression and provide first evidence for a role of epigenetic silencing of AMOG in malignant glioma cells. © 2006 Wiley‐Liss, Inc.
Neuropathology, tremor and electromyogram in rats exposed to manganese phosphate/sulfate mixture
Authors: Salehi Fariba , Normandin Louise , Krewski Daniel , Kennedy Greg , Philippe Suzanne , Zayed Joseph 
Published: July 2006

AbstractIn Canada, Methylcyclopentadienyl manganese tricarbonyl (MMT) replaced tetraethyl lead in gasoline as an antiknock agent from 1976 until 2003. The combustion of MMT leads to increased manganese (Mn) concentrations in the atmosphere, and represents one of the main sources of human exposure to Mn. The nervous system is the major target of the toxicity of Mn and Mn compounds. The purpose of this study was to investigate exposure‐response relationships for neuropathology and tremor, and the associated electromyogram (EMG), following subchronic inhalation exposure of rats to a mixture of Mn phosphate/sulfate particles. Rats were exposed 6 h per day, 5 days per week for 13 consecutive weeks at 30, 300 or 3000 µg m−3 Mn phosphate/sulfate mixture and compared with controls. Half of the rats had EMG electrodes implanted in the gastrocnemius muscle of the hind limb to assess tremor at the end of Mn exposure. Two days after the end of Mn exposure, rats were killed by exsanguination and Mn concentrations in the brain (caudate putamen, globus pallidus and frontal cortex) were determined by neutron activation analysis while neuropathology was assessed by counting neuronal cells in 2.5 mm × 2.5 mm grid areas. Increased Mn concentrations were observed in all brain sections at the highest level of exposure. The neuronal cell loss was significantly different in the globus pallidus and the caudate putamen at the highest level of exposure (3000 µg m−3). No sign of tremor was observed among the rats. In conclusion, exposure to a high level of Mn phosphate/sulfate mixture brought on neuropathological changes in a specific area of the brain; however, no sign of tremor was observed. Copyright © 2006 John Wiley & Sons, Ltd.
Treatment of chromate‐polluted groundwater in a 200 dm3 pilot bioreactor fed with hydrogen
Authors: Battaglia‐Brunet Fabienne , Touzé Solène , Michel Caroline , Ignatiadis Ioannis 
Published: July 2006

AbstractChromate is a highly soluble, toxic and carcinogenic oxyanion commonly found in groundwaters and soils. A 200 dm3 pilot bioreactor was designed to treat typical Cr(VI)‐polluted groundwater. A fixed bed column was filled with pozzolana, inoculated with a bacterial population containing the sulfate‐reducing organism Desulfomicrobium norvegicum and fed with an H2 + CO2 gas mixture. The pilot was operated under continuous feed conditions for 3 months, first with a synthetic solution and then with real polluted groundwater containing 15 mg dm−3 Cr(VI). The residence time was decreased to 7 h, while the Cr(VI) concentration in the outflow remained lower than 0.2 mg dm−3. The bacterial population did not need any organic carbon supply thanks to acetogenesis. The highest Cr(VI) reduction rate was 2.2 mg dm−3 h−1. The CO2 flow rate was regulated in order to maintain the pH in the interval 7.5–8.5. The CO2 consumption rate increased with feed flow rate and sulfate reduction activity. The process worked satisfactorily between 10 and 35 °C. Copyright © 2006 Society of Chemical Industry
Ambiguous connections: entitlements and responsibilities of global networking
Authors: Mansell Robin 
Published: July 2006

AbstractThis article examines efforts to provide low‐cost Internet access devices for the poor in the light of debates about the appropriate role of information and communication technologies in development and the priority that should be given to enabling the poor to become connected to global networks. A critical analysis of recent private sector initiatives to design low‐cost laptop computers is offered in the wider context of the need to consider the politics of technology and the insights that can be drawn from ongoing debates about ICT4D and the need for public dialogue and evaluation of investment priorities in forums that enable the participation of the poor. Copyright © 2006 John Wiley & Sons, Ltd.
Should teachers stay at home? The impact of international teacher mobility
Authors: Appleton Simon , Morgan W. John , Sives Amanda 
Published: July 2006

AbstractThis article assesses the impact of international teacher migration on developing countries, based on a project covering Botswana, England, Jamaica and South Africa. It draws upon fieldwork conducted in 2003, including surveys of schools, migrant teachers and trainee teachers. The article estimates the extent of the movements and argues that they are largely transitional. The salary gains from migration are reported, along with estimates of the costs to sending countries in terms of training subsidies. International recruitment is not found to lead to harmful shortages of teachers in Jamaica and South Africa, but may ‘cream off’ the more effective teachers. Copyright © 2006 John Wiley & Sons, Ltd.
Sahelian action spaces: an examination of livelihood configurations in a rural Hausa community
Authors: Manvell Adam 
Published: July 2006

AbstractThe premise of this article is that understanding how people are connected in time and space can provide important insights for policies that seek to improve the livelihoods of the poor. The concept of action space is presented as means of situating the individual within their unique set of temporal and spatial connections. Data from a rural Hausa community in Niger are examined regarding three inter‐related factors connecting individuals: marriage, personal communities and migration. The article concludes with a discussion of how the mobile telephone throws into focus the fundamental problems of managing these connections. Copyright © 2006 John Wiley & Sons, Ltd.
Women migrant workers in the UK: social capital, well‐being and integration
Authors: Giusta Marina Della , Kambhampati Uma 
Published: July 2006

AbstractThis paper addresses the role of social connections in helping women migrants to settle in the UK. We focus on micro‐ and macro‐social capital with the former including local social networks and organisation (comprising immediate family, other immigrants, neighbours, churches) and the latter including experience with local government supporting institutions. In this context, we present results from a pilot study based on data collected amongst women immigrant workers in the care sector in the UK. A majority of respondents in our sample come from Africa and Asia and 62 per cent arrived without family. Our results indicate that while education decreases the extent to which women in our sample feel settled, contact with the local community as well as living within an immigrant community helped the women to feel settled. Finally, their experience with services like housing and immigration proved very significant. Copyright © 2006 John Wiley & Sons, Ltd.
An efficient two step purification and molecular characterization of β‐galactosidases from Aspergillus oryzae
Authors: Todorova‐Balvay Daniela , Stoilova Ivanka , Gargova Stoyanka , Vijayalakshmi Mookambeswaran A. 
Published: July 2006

Abstractβ‐Galactosidases (β‐D‐galactoside‐galactohydrolases (EC 3.2.1.23), lactases) are important industrial enzymes used for the hydrolysis of lactose from milk and milk whey. These enzymes are produced by different organisms and purified by multi‐step procedures. The multi‐step purification schemes are cost and time ineffective which can also lead to poor yield, denaturation and loss of enzymatic activity. In our study, extracellular β‐galactosidase from mutant strain Aspergillus oryzaeH26‐10‐7 was purified by a two step procedure, Metal‐ion Affinity Chromatography (IMAC) followed by size‐exclusion separation. Purified enzyme was characterized by sodium dodecyl Sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) and zymographic analysis. This fungal β‐galactosidase was characterized as a protein corresponding to 113 kDa. Enzyme from mutant strain was found to have five times higher catalytic activity on the synthetic substrate o‐nitrophenyl‐β‐D‐galactopyranoside (ONPG) compared to the wild type enzyme. Moreover, the mutant enzyme was more thermo resistant compared to the wild type. This highly important technological characteristic can be exploited in food industry. Moreover, based on the IMAC patterns of wild type and mutant enzymes, similarities in their His topography were supposed. Copyright © 2006 John Wiley & Sons, Ltd.
pSTAT1, pSTAT3, and T‐bet expression in peripheral blood mononuclear cells from relapsing‐remitting multiple sclerosis patients correlates with disease activity
Authors: Frisullo Giovanni , Angelucci Francesco , Caggiula Marcella , Nociti Viviana , Iorio Raffaele , Patanella Agata Katia , Sancricca Cristina , Mirabella Massimiliano , Tonali Pietro Attilio , Batocchi Anna Paola 
Published: July 2006

AbstractMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system, and it is considered to be a T helper 1 (Th1) cell‐mediated autoimmune disease. T‐bet has been identified as a key transcription factor for the development of Th1 cells and the induction of interferon (IFN)‐γ production. T‐bet is induced during T‐cell activation by the IFN‐γ signal transducer and activator of transcription (STAT)‐1 signalling pathway. In this study we found an up‐regulation of T‐bet and pSTAT1 in peripheral blood CD4+ and CD8+ T cells and monocytes from relapsing‐remitting MS patients in relapse compared with patients in remission and with healthy subjects. The increased expression of pSTAT1 strongly correlated with T‐bet expression in CD4+ and CD8+ cells and monocytes from patients in relapse and was associated with an increased production of IFN‐γ by peripheral blood mononuclear cells (PBMCs). pSTAT3 was also up‐regulated in CD4+ and CD8+ cells and monocytes from patients in relapse and was associated with an increased production of interleukin (IL)‐10 but not of IL‐6. pSTAT1, pSTAT3, and T‐bet expression strongly correlated with Gd‐DTPA‐enhanced lesions on brain and spinal cord magnetic resonance imaging. Our data show for the first time that there is an up‐regulation of type 1 immunity‐correlated transcription factors such as STAT1 and T‐bet in peripheral blood subpopulations of MS patients in the active phase of disease. The evaluation of T‐bet and pSTAT1 expression in peripheral blood CD4+, CD8+ T cells and monocytes could be used as a marker of disease activity in relapsing‐remitting MS. © 2006 Wiley‐Liss, Inc.
A gap 1 cardinal transfer theorem
Authors: Villegas‐Silva Luis M. 
Published: July 2006

AbstractWe extend the gap 1 cardinal transfer theorem (κ +, κ ) → (λ +, λ ) to any language of cardinality ≤λ, where λ is a regular cardinal. This transfer theorem has been proved by Chang under GCH for countable languages and by Silver in some cases for bigger languages (also under GCH). We assume the existence of a coarse (λ, 1)‐morass instead of GCH. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kolmogorov complexity and set theoretical representations of integers
Authors: Ferbus‐Zanda Marie , Grigorieff Serge 
Published: July 2006

AbstractWe reconsider some classical natural semantics of integers (namely iterators of functions, cardinals of sets, index of equivalence relations) in the perspective of Kolmogorov complexity. To each such semantics one can attach a simple representation of integers that we suitably effectivize in order to develop an associated Kolmogorov theory. Such effectivizations are particular instances of a general notion of “self‐enumerated system” that we introduce in this paper. Our main result asserts that, with such effectivizations, Kolmogorov theory allows to quantitatively distinguish the underlying semantics. We characterize the families obtained by such effectivizations and prove that the associated Kolmogorov complexities constitute a hierarchy which coincides with that of Kolmogorov complexities defined via jump oracles and/or infinite computations (cf. [6]). This contrasts with the well‐known fact that usual Kolmogorov complexity does not depend (up to a constant) on the chosen arithmetic representation of integers, let it be in any base n ≥ 2 or in unary. Also, in a conceptual point of view, our result can be seen as a mean to measure the degree of abstraction of these diverse semantics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
n‐linear weakly Heyting algebras
Authors: Celani Sergio A. 
Published: July 2006

AbstractThe present paper introduces and studies the variety 𝒲ℋ︁n of n‐linear weakly Heyting algebras. It corresponds to the algebraic semantic of the strict implication fragment of the normal modal logic K with a generalization of the axiom that defines the linear intuitionistic logic or Dummett logic. Special attention is given to the variety 𝒲ℋ︁2 that generalizes the linear Heyting algebras studied in [10] and [12], and the linear Basic algebras introduced in [2]. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The covering number and the uniformity of the ideal ℐf
Authors: Osuga Noboru 
Published: July 2006

AbstractLet f, g ∈ ω ω . We will denote by g ≫ f that for every k < ω, f (n k ) ≤ g (n ) except for finitely many n . The ideal ℐf on ω 2 is the collection of sets X such that, for some g ≫ f and τ ∈ ∏n <ω g (n )2, every x ∈ X satisfies τ (n ) ⊂ x for infinitely many n . In the present paper, we will prove the consistency of cov(ℐf ) < 𝔠 and non(ℐf ) < 𝔠. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On hyper‐torre isols
Authors: Barback Joseph 
Published: July 2006

AbstractIn this paper we present a contribution to a classical result of E. Ellentuck in the theory of regressive isols. E. Ellentuck introduced the concept of a hyper‐torre isol, established their existence for regressive isols, and then proved that associated with these isols a special kind of semi‐ring of isols is a model of the true universal‐recursive statements of arithmetic. This result took on an added significance when it was later shown that for regressive isols, the property of being hyper‐torre is equivalent to being hereditarily odd‐even. In this paper we present a simplification to the original proof for establishing that equivalence. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel One‐Step Route for Preparing Amphiphilic Block Copolymers of Styrene and N‐Isopropylacrylamide in a Microemulsion
Authors: Zheng Cheng , He Wei‐Dong , Liu Wei‐Jun , Li Jian , Li Jun‐Fang 
Published: July 2006

AbstractSummary: Copolymerizations of St and NIPAM have been carried out through interfacial‐initiated microemulsion polymerization in a frozen state. FT‐IR and NMR spectroscopies confirm the occurrence of copolymerization between the two monomers. DSC analysis shows the existence of two glass transition temperatures of the resultant copolymers. The micellization of the copolymers is investigated by DLS and the temperature‐responsive behavior of the resultant micelles is observed. DSC and DLS results reveal the block feature of the obtained copolymers. Thus amphiphilic poly(styrene‐block‐N‐isopropylacrylamide) is prepared by a one‐step interfacial‐initiated microemulsion polymerization.Hydrodynamic radius of the micellar particles formed by (left), and a typical DSC trace of (right), the poly(styrene‐block‐N‐isopropylacrylamide) prepared here.magnified imageHydrodynamic radius of the micellar particles formed by (left), and a typical DSC trace of (right), the poly(styrene‐block‐N‐isopropylacrylamide) prepared here.
Catch and Release of DNA in Coacervate‐Dispersed Gels
Authors: Ohsugi Asami , Furukawa Hidemitsu , Kakugo Akira , Osada Yoshihito , Gong Jian Ping 
Published: July 2006

AbstractSummary: We have synthesized novel coacervate‐droplet gels, which were applied to controlling the transportation of DNA in electrophoresis. Coacervate droplets are colloidal particles and they are usually composed of positive and negative polyelectrolytes. However, the polyzwitterion (polyampholyte) PDMAPS can form coacervate droplets in water by itself, since PDMAPS has both positive and negative charges in each side group of main chain. Coacervate droplets have a unique nature and can catch charged macromolecules such as DNA. In order to utilize the nature of the PDMAPS coacervate droplets for the catch and release of DNA, we stabilized PDMAPS droplets in gels. The droplets catch the DNA in electrophoresis and the release of DNA can be controlled by temperature and salt addition.Electrophoresis of DNA, using coacervate‐dispersed PAAm gels, prepared at various PDMAPS concentrations. The circles indicate the PAAm gels embedded in agarose gels.magnified imageElectrophoresis of DNA, using coacervate‐dispersed PAAm gels, prepared at various PDMAPS concentrations. The circles indicate the PAAm gels embedded in agarose gels.
A New Approach to Prepare Poly(ethylene terephthalate)/Silica Nanocomposites with Increased Molecular Weight and Fully Adjustable Branching or Crosslinking by SSP
Authors: Bikiaris Dimitris , Karavelidis Vassilis , Karayannidis George 
Published: July 2006

AbstractSummary: In the present study, it has been unexpectedly found that solid‐state polycondensation (SSP) can act as a facile method to prepare poly(ethylene terephthalate)/silica (PET/SiO2) nanocomposites with high molecular weight and an adjustable degree of branching or crosslinking. Fumed silica, with its surface silanol groups, seems to participate in some kind of reaction, probably esterification with the hydroxy end‐groups of PET, during SSP, to act as a multifunctional chain extender. Differential scanning calorimetry and FT‐IR spectroscopy reveal this ability of the silanol groups. The molecular weight increase depends on the used temperatures of SSP as well as on the amount of SiO2 added. As the amount of silica increases the rate of increase of the intrinsic viscosity slows because of the higher extent of branching. At 5 wt.‐% SiO2 the extensive branching produces a crosslinked polymeric material. Such polyesters with increased molecular weight and low silica content could be suitable for blown bottle production, while the high SiO2 content and adjustable branching or crosslinking could make them ideal high‐melt‐strength resins suitable for the preparation of low‐density closed‐shell foams.Schematic representation of PET/SiO2 crosslinked macromolecules.magnified imageSchematic representation of PET/SiO2 crosslinked macromolecules.