bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Grazing on Restoration of Endemic Dwarf Pine (Pinus culminicola Andresen et Beaman) Populations in Northeastern Mexico
Authors: Jiménez J , Jurado E , Aguirre O , Estrada E
Published: March 2005

A pilot experiment designed to test the effect of cattle, small mammals, and elevation on the success of reforestation of an endemic dwarf pine species in northeastern Mexico was implemented. Pinus culminicola (Andresen et Beaman) grows only in four high peaks in the Sierra Madre Oriental and is under pressure from grazing, wildfires, and human activities such as mining, road development for timber extraction, and telecommunication and aerial navigation devices. We planted and monitored 2‐year‐old seedlings at three elevations within the natural distribution range of this species at Cerro El Potosí in Nuevo León, Mexico. At each elevation three treatments were established: (1) seedlings protected from cattle plus small mammals, (2) seedlings protected from cattle, and (3) seedlings with free access to cattle and small mammals. Seedling survival was approximately 50% in (1) after 4 years, but there were no surviving seedlings with free access to cattle. Elevation in general did not account for variation in survival. Seedling growth was poor during the 4 years, which implies that seedlings remain susceptible to grazing and trampling by cattle and small mammals. The implications for a large‐scale restoration program are discussed.
Restoring Lepidopteran Communities to Oak Savannas: Contrasting Influences of Habitat Quantity and Quality
Authors: Summerville K.S. , R M. Steichen , Lewis M.N.
Published: March 2005

Ecological restoration is deemed important for the long‐term conservation of biodiversity, but ecologists still lack an understanding of how habitat availability and habitat quality in a restored system interact to determine species diversity. This problem seems particularly apparent in Tallgrass Prairie and savanna ecoregions, where restored management units represent the majority of extant habitat. In this study, we tested three principal hypotheses, each stating that the diversity of Lepidoptera would be greater in (1) patches of savanna habitat that were larger; (2) patches that were of higher habitat quality; and (3) patches that had greater connectivity to management units of similar physiognomy. Lepidoptera were sampled in 2003 from 13 unmanaged woodland remnants within Neal Smith National Wildlife Refuge, a 2,292‐ha prairie and savanna reconstruction project. We also measured 11 environmental variables within each site to assess variation in habitat quantity and quality. Principal components analysis (PCA) was used to identify major gradients of environmental variation among the 13 sites. Our PCA differentiated among woodlands along three environmental gradients, defined by (1) stand size, shape, topography, and oak dominance; (2) degree of disturbance; and (3) isolation. Total lepidopteran species richness, however, was only predicted by variation in the first principal component. Species richness of Lepidoptera known to be oak specialists was significantly affected by variation along all three PCA gradients. Surprisingly, more isolated woodland remnants contained a greater richness of oak feeders. Our results suggest that approaches to restoring oak savannas should emphasize aspects of both habitat quantity and quality. Beyond making individual management units larger, priority sites for restoration should possess a low importance of trees that are indicative of past habitat disturbance (e.g., Honey locust, White mulberry) even if canopy closure is substantial. Connectivity among restored habitats may benefit savanna moth communities only when habitat linkages contain a flora similar in composition to focal patches.
The Restoration of Degraded Mountain Woodlands: Effects of Seed Provenance and Microsite Characteristics onPolylepis australisSeedling Survival and Growth in Central Argentina
Authors: Renison D , Cingolani A.M. , Suarez R , Menoyo E , Coutsiers C , Sobral A , Hensen I
Published: March 2005

South American high‐mountain ecosystems are greatly influenced by human disturbance. In the mountains of Córdoba, Argentina,Polylepis australis(Rosaceae) woodlands are currently highly fragmented and subject to extensive burning and livestock grazing, resulting in severe changes of habitat characteristics, which hamper natural regeneration. In order to find out how to achieve successful reforestation, we comparedP. australisseedling survival and growth and the development of a shrubby habit for two seed provenances and different planting microsites. Survival of planted seedlings after 5 years was 70%, with most deaths (19%) in the first year and declining mortality with ongoing establishment. Survival did not show any relationship with seed provenance or microsite characteristics. Height growth averaged 34.6 ± 1.2 cm in 5 years. Seedlings produced from seeds collected in a well‐preserved woodland grew taller and showed a higher tendency for development of shrubby habit than those produced from seeds collected in a degraded woodland. Seedlings planted in more degraded microsites with exposed soil or rock due to past grazing pressure grew less and developed a more shrubby habit than those planted in better preserved microsites. Our results show that restoration of degraded areas withP. australisis possible and that there is potential to improve restoration success with a careful selection of seed provenance and planting microsites.
Epilogue: Toward a Transdisciplinary Science of Ecological and Cultural Landscape Restoration
Authors: Naveh Z
Published: March 2005

To bridge the gaps between restoration as a science and as a practice, restoration ecology has to broaden its scope toward transdisciplinarity in close cooperation with landscape ecologists and other holistic environmentally oriented scientists, professionals, practitioners, and stakeholders. For restoration, the ongoing transdisciplinary scientific revolution has opened new insights to cope with the complex bio‐hydro‐ and human‐ecological network relations. The Total Human Ecosystem (THE), integrating humans with all other organisms and their total environment at the highest level of the global hierarchy, should become the unifying holistic paradigm for all synthetic “eco‐disciplines.” These should link ecological knowledge, wisdom, and ethics with their scientific and professional expertise from the natural and social sciences and the humanities. As the tangible matrix for all organisms, including humans, our industrial Total Human Landscape is the concrete spatial and functional system of the THE. It forms a closely interlaced network of solar energy–powered natural and seminatural biosphere landscapes and fossil energy–powered urban and agro‐industrial technosphere landscapes. The self‐organizing and self‐creative restoration capacities of biosphere landscapes are driven by mutually amplifying auto‐ and cross‐catalytic feedback loops, but the rapidly expanding technosphere landscapes are driven by destabilizing “run‐away” feedback loops. To prevent a global breakdown and to ensure the sustainable future for both humankind and nature, these positive feedbacks have to be counteracted by restraining, cultural feedbacks of environmental planning and management, conservation, and restoration. As the theme of this special issue alludes to, this template should become an integral part of an urgently needed sustainability revolution, to which the transdisciplinary landscape restoration could contribute its important share.
Frequent microsatellite alterations of chromosome locus 4q13.1 in oral squamous cell carcinomas
Authors: Lin Shu‐Chun , Chang Mei‐Fong , Chung Ming‐Yi , Chang Che‐Shoa , Kao Shou‐Yen , Liu Chung‐Ji , Chang Kuo‐Wei
Published: March 2005

Background:  Studies have revealed that losses of chromosome 4q24–25 regions are frequent in cancers including head and neck squamous cell carcinoma. Our previous comparative genomic hybridization analysis showed extensive losses of chromosome arm 4q in oral squamous cell carcinoma (OSCC).

Methods:  To be more precise in mapping the potential regions of allelic losses and to understand the microsatellite instability (MSI) on 4q involving in oral pathogenesis, we performed allelotypings using eight polymorphic markers. Microsatellite analyses were first performed on 100 randomly selected controls to confirm the high informative rates of markers. Twenty OSCC tissues were microdissected from surgical specimens for microsatellite alterations (MA) analysis.

Results:  MA was observed in 95% OSCC cases. The most eminently altered locus was 4q13.1 (75%), followed by 4q22.2 and 4q32.1 (55%). Allelic losses also occurred most frequently on these loci. Thirty‐five percent cases had MA spanning 4q13.1 to 4q21.1. MSI occurred in 35% OSCC, at a lesser extent compared with allelic losses. The most common locus for MSI was 4q21.2 (20%). In addition, 4q MSI was significantly associated with the lymph node metastasis of OSCC (P = 0.01). So far, most tumor suppressor genes on 4q have not been specified.

Conclusion:  Our results were additive to previous findings and proposed novel scenario of suppressor loci located at 4q13.1–21.1 whose inactivation could be important for progression of OSCC.
Hepatitis C virus‐associated oral lichen planus: is the geographical heterogeneity related to HLA‐DR6?
Authors: Carrozzo M. , Brancatello F. , Dametto E. , Arduino P. , Pentenero M. , Rendine S. , Porter S. R. , Lodi G. , Scully C. , Gandolfo S.
Published: March 2005

Background:  The association between hepatitis C virus (HCV) and oral lichen planus (OLP) is more common in the Mediterranean area and Japan, possibly because of immunogenetic factors.

Methods:  Intermediate‐resolution HLA‐DRB typing by hybridization with oligonucleotide probes was performed in 31 Italian OLP patients with HCV infection, in 45 Italian OLP and in 48 British OLP patients without HCV infection. As healthy controls we included data from 145 unrelated Italian and 101 unrelated British bone marrow donors.

Results:  Italian HCV+ve OLP patients possessed the HLA‐DR6 allele more frequently than Italian and British OLP patients without HCV infection (51.6% vs. 17.7% vs. 16.7%; P corrected = 0.028 and 0.017, respectively). There was no difference in the frequency of the HLA‐DR6 allele between Italian and British control subjects.

Conclusions:  The present data suggest that HLA‐DR6 may be responsible for the peculiar geographic heterogeneity of the association between HCV and OLP.
The phenotype of in vitro reconstituted normal human oral epithelium is essentially determined by culture medium
Authors: Costea Daniela Elena , Dimba Anne Okumo Elizabeth , Loro Lado Lako , Vintermyr Olav Karsten , Johannessen Anne Christine
Published: March 2005

Objective:  To evaluate the role of various culture media and serum supplement on growth of oral cells in monolayer, and on morphogenesis of in vitro reconstituted normal human oral epithelium.

Methods:  Primary keratinocytes and fibroblasts were isolated from normal human buccal mucosa. The monolayers were assessed by growth curve analysis and morphology. The organotypic cultures were evaluated by morphometry, immunohistochemistry, and TUNEL.

Results: 
FAD medium (a 3:1 mixture of Dulbecco's modified Eagle's medium and Ham's F12 medium) was able to support fibroblast growth in defined conditions, and to diminish the negative effect of physiological Ca concentration on keratinocytes in monolayers. Medium type had a profound influence on morphogenesis of in vitro reconstituted human oral epithelium. FAD medium was superior to other types of medium tested in supporting both epithelial growth and differentiation. Defined conditions supported epithelial morphogenesis equally well as serum‐containing medium.

Conclusions:  This study points to an essential role of medium composition for optimized growth and differentiation of primary organotypic cultures.
Pharmacokinetics and clinical effects of mono‐l‐aspartyl chlorin e6 (NPe6) photodynamic therapy in adult patients with primary or secondary cancer of the skin and mucosal surfaces
Authors: Chan Andrew L. , Juarez Maya , Allen Roblee , Volz William , Albertson Timothy
Published: March 2005

Background/Purpose: Mono‐l‐aspartyl chlorin e6 (NPe6) is a photosensitizer that exhibits chemical purity, absorption at 664 nm wavelength and may be useful in photodynamic therapy (PDT).

Methods: This open label phase I clinical trial at the University of California, Davis Medical Center examined the pharmacokinetic properties of Npe6 and clinical response to PDT with this photosensitizer. A single intravenous dose of Npe6 was administered to 14 cancer patients with superficial malignancies (basal cell carcinoma=22 lesions, squamous cell cancer=13 lesions, papillary carcinoma=14 lesions). Patients received one of five ascending doses (0.5 mg/kg (n=4), 1.0 mg/kg (n=3), 1.65 mg/kg (n=3), 2.5 mg/kg (n=3), or 3.5 mg/kg (n=1)) 4–8 h prior to light activation. The total light dose (range 25–200 J/cm2) depended on the tumor shape and size. Light was delivered using an argon‐pumped tunable dye laser. Serum NPe6 concentrations were measured over a 28‐day period. The toxicity and cutaneous clinical efficacy of NPe6 were observed.

Results: Four weeks post‐PDT, 20 of 22 basal cell carcinoma tumors (91%) showed a complete response. Eighteen of 27 other malignant cutaneous tumors showed a complete (n=15/27, 56%) or partial (n=3/27, 11%) response. Fewer non‐responders were seen at an Npe6 dose level of 1.65 mg/kg or higher. Only 2 of 14 patients experienced an adverse event that was definitely related to NPe6 administration. Photosensitivity resolved within 1 week of NPe6 dosing in 12 of 14 patients. Analysis of serum levels of 11 individual patients indicated that a two‐compartment model with a residual phase best fits the data. The mean α, β, and terminal half‐lives were 8.63±2.92, 105.90±37.59 and 168.11±53.40 h (±1 SD), respectively. The observed mean volume of distribution was 5.94±2.55 l, and the mean clearance was 0.0394±0.0132 l/h. These values were independent of the dose administered.

Conclusion: The photosensitizer, NPe6, was well tolerated with minimal phototoxic side effects, and demonstrated preliminary efficacy against cutaneous malignancies.
Fixed solar urticaria induced by UVA and visible light: a report of a case
Authors: Tuchinda C. , Leenutaphong V. , Sudtim S. , Lim H. W.
Published: March 2005

Fixed solar urticaria (FSU) is a rare and less severe subgroup of solar urticaria. It is characterized by urticarial eruptions, which occurs on the same parts of the body following sun exposure. The lesions are reproducible at the same sites with similar morphology and distribution pattern after repeated sun exposure. The action spectrum of FSU is broad (300–700 nm). We reported a case of FSU induced by UVA and visible light. The patient responded well to cetirizine treatment.
Characterization of Endocytic Vesicles Using Magnetic Microbeads Coated with Signalling Ligands
Authors: Li Hai‐sheng , Stolz Donna B. , Romero Guillermo
Published: March 2005

Iron microbeads coated with the protein ligands insulin and EGF (Fe‐INS and Fe‐EGF) were prepared. Examination of the traffic of these ligand‐coated microbeads demonstrated their internalization via clathrin‐coated vesicles. Using magnetic methods, we have purified vesicles derived from the endocytic pathway. Vesicles prepared by this method are essentially free of contamination with other endomembrane compartments. Examination of the vesicles derived from cells treated with Fe‐INS beads demonstrated the presence of the components of the Ras/Erk cascade on their surface. We conclude that the coupling of the Erk‐signalling cascade induced by insulin takes place on the surface of endocytic vesicles derived from the internalization of the insulin receptor.
Effect of coenzyme modification on the structural and catalytic properties of wild‐type transketolase and of the variant E418A from Saccharomyces cerevisiae
Authors: Golbik Ralph , Meshalkina Ludmilla E. , Sandalova Tatjana , Tittmann Kai , Fiedler Erik , Neef Holger , König Stephan , Kluger Ronald , Kochetov German A. , Schneider Gunter , Hübner Gerhard
Published: March 2005

Transketolase from baker's yeast is a thiamin diphosphate‐dependent enzyme in sugar metabolism that reconstitutes with various analogues of the coenzyme. The methylated analogues (4′‐methylamino‐thiamin diphosphate and N1′‐methylated thiamin diphosphate) of the native cofactor were used to investigate the function of the aminopyrimidine moiety of the coenzyme in transketolase catalysis. For the wild‐type transketolase complex with the 4′‐methylamino analogue, no electron density was found for the methyl group in the X‐ray structure, whereas in the complex with the N1′‐methylated coenzyme the entire aminopyrimidine ring was disordered. This indicates a high flexibility of the respective parts of the enzyme‐bound thiamin diphosphate analogues. In the E418A variant of transketolase reconstituted with N1′‐methylated thiamin diphosphate, the electron density of the analogue was well defined and showed the typical V‐conformation found in the wild‐type holoenzyme [Lindqvist Y, Schneider G, Ermler U, Sundstrøm M (1992) EMBO J11, 2373–2379]. The near‐UV CD spectrum of the variant E418A reconstituted with N1′‐methylated thiamin diphosphate was identical to that of the wild‐type holoenzyme, while the CD spectrum of the variant combined with the unmodified cofactor did not overlap with that of the native protein. The activation of the analogues was measured by the H/D‐exchange at C2. Methylation at the N1′ position of the cofactor activated the enzyme‐bound cofactor analogue (as shown by a fast H/D‐exchange rate constant). The absorbance changes in the course of substrate turnover of the different complexes investigated (transient kinetics) revealed the stability of the α‐carbanion/enamine as the key intermediate in cofactor action to be dependent on the functionality of the 4‐aminopyrimidine moiety of thiamin diphosphate.
Dehydroepiandrosterone inhibits the proliferation of human umbilical vein endothelial cells by enhancing the expression of p53 and p21, restricting the phosphorylation of retinoblastoma protein, and is androgen‐ and estrogen‐receptor independent
Authors: Zapata Estrella , Ventura José L. , De la Cruz Karina , Rodriguez Emma , Damián Pablo , Massó Felipe , Montaño Luis F. , López‐Marure Rebeca
Published: March 2005

Dehydroepiandrosterone (DHEA), a steroid hormone, modified the proliferation of human umbilical vein endothelial cells in a dose‐dependent manner. Its inactive sulfate ester (DHEA‐S) and two of its metabolites – estradiol and testosterone – had no inhibitory effect at physiological concentrations. Antiproliferation was associated with arrest in the G1 phase of the cell cycle, but not with cell death, as evaluated by cleavage of poly(ADP‐ribose) polymerase and exposure of phosphatidylserine. The effect was not blocked by inhibitors of androgen or estrogen receptors. DHEA diminished the levels of phosphorylated retinoblastoma protein and increased the expression of p53 and p21 mRNAs. These results show that DHEA inhibits endothelial cell proliferation by regulating cell cycle relevant proteins through a cytoplasmic steroid hormone‐independent pathway.
Entamoeba histolytica TATA‐box binding protein binds to different TATA variants in vitro
Authors: de Dios‐Bravo Guadalupe , Luna‐Arias Juan Pedro , Riverón Ana María , Olivares‐Trejo José J , López‐Camarillo César , Orozco Esther
Published: March 2005

The ability of Entamoeba histolytica TATA binding protein (EhTBP) to interact with different TATA boxes in gene promoters may be one of the key factors to perform an efficient transcription in this human parasite. In this paper we used several TATA variants to study the in vitro EhTBP DNA‐binding activity and to determine the TATA‐EhTBP dissociation constants. The presence of EhTBP in complexes formed by nuclear extracts (NE) and the TATTTAAA oligonucleotide, which corresponds to the canonical TATA box for E. histolytica, was demonstrated by gel‐shift assays. In these experiments a single NE‐TATTTAAA oligonucleotide complex was detected. Complex was retarded by anti‐EhTBP Igs in supershift experiments and antibodies also recognized the cross‐linked complex in Western blot assays. Recombinant EhTBP formed specific complexes with TATA variants found in E. histolytica gene promoters and other TATA variants generated by mutation of TATTTAAA sequence. The dissociation constants of recombinant EhTBP for TATA variants ranged between 1.04 (±0.39) × 10−11 and 1.60 (±0.37) × 10−10 m. TATTTAAA and TAT_ _AAA motifs presented the lowest KD values. Intriguingly, the recombinant EhTBP affinity for TATA variants is stronger than other TBPs reported. In addition, EhTBP is more promiscuous than human and yeast TBPs, probably due to modifications in amino acids involved in TBP‐DNA binding.
Conserved pore‐forming regions in polypeptide‐ transporting proteins
Authors: Moslavac Suncana , Mirus Oliver , Bredemeier Rolf , Soll Jürgen , von Haeseler Arndt , Schleiff Enrico
Published: March 2005

Transport of solutes and polypeptides across membranes is an essential process for every cell. In the past, much focus has been placed on helical transporters. Recently, the β‐barrel‐shaped transporters have also attracted some attention. The members of this family are found in the outer bacterial membrane and the outer membrane of endosymbiotically derived organelles. Here we analyze the features and the evolutionary development of a specified translocator family, namely the β‐barrel‐shaped polypeptide‐transporters. We identified sequence motifs, which characterize all transporters of this family, as well as motifs specific for a certain subgroup of proteins of this class. The general motifs are related to the structural composition of the pores. Further analysis revealed a defined distance of two motifs to the C‐terminal portion of the proteins. Furthermore, the evolutionary relationship of the proteins and the motifs are discussed.
Caspase‐2 is resistant to inhibition by inhibitor of apoptosis proteins (IAPs) and can activate caspase‐7
Authors: Ho Po‐ki , Jabbour Anissa M. , Ekert Paul G. , Hawkins Christine J.
Published: March 2005

Caspases are a family of cysteine proteases with roles in cytokine maturation or apoptosis. Caspase‐2 was the first pro‐apoptotic caspase identified, but its functions in apoptotic signal transduction are still being elucidated. This study examined the regulation of the activity of caspase‐2 using recombinant proteins and a yeast‐based system. Our data suggest that for human caspase‐2 to be active its large and small subunits must be separated. For maximal activity its prodomain must also be removed. Consistent with its proposed identity as an upstream caspase, caspase‐2 could provoke the activation of caspase‐7. Caspase‐2 was not subject to inhibition by members of the IAP family of apoptosis inhibitors.
A novel glycogen‐targeting subunit of protein phosphatase 1 that is regulated by insulin and shows differential tissue distribution in humans and rodents
Authors: Munro Shonagh , Ceulemans Hugo , Bollen Mathieu , Diplexcito Julie , Cohen Patricia T.W.
Published: March 2005

Stimulation of glycogen‐targeted protein phosphatase 1 (PP1) activity by insulin contributes to the dephosphorylation and activation of hepatic glycogen synthase (GS) leading to an increase in glycogen synthesis. The glycogen‐targeting subunits of PP1, GL and R5/PTG, are downregulated in the livers of diabetic rodents and restored by insulin treatment. We show here that the mammalian gene PPP1R3E encodes a novel glycogen‐targeting subunit of PP1 that is expressed in rodent liver. The phosphatase activity associated with R3E is slightly higher than that associated with R5/PTG and it is downregulated in streptozotocin‐induced diabetes by 60–70% and restored by insulin treatment. Surprisingly, although mRNA for R3E is most highly expressed in rat liver and heart muscle, with only low levels in skeletal muscle, R3E mRNA is most abundant in human skeletal muscle and heart tissues with barely detectable levels in human liver. This species‐specific difference in R3E mRNA expression has similarities to the high level of expression of GL mRNA in human but not rodent skeletal muscle. The observations imply that the mechanisms by which insulin regulates glycogen synthesis in liver and skeletal muscle are different in rodents and humans.
An engineered disulfide bridge mimics the effect of calcium to protect neutral protease against local unfolding
Authors: Dürrschmidt Peter , Mansfeld Johanna , Ulbrich‐Hofmann Renate
Published: March 2005

The extreme thermal stabilization achieved by the introduction of a disulfide bond (G8C/N60C) into the cysteine‐free wild‐type‐like mutant (pWT) of the neutral protease from Bacillus stearothermophilus[Mansfeld J, Vriend G, Dijkstra BW, Veltman OR, Van den Burg B, Venema G, Ulbrich‐Hofmann R & Eijsink VG (1997) J Biol Chem272, 11152–11156] was attributed to the fixation of the loop region 56–69. In this study, the role of calcium ions in the guanidine hydrochloride (GdnHCl)‐induced unfolding and autoproteolysis kinetics of pWT and G8C/N60C was analyzed by fluorescence spectroscopy, far‐UV CD spectroscopy and SDS/PAGE. First‐order rate constants (kobs) were evaluated by chevron plots (ln kobs vs. GdnHCl concentration). The kobs of unfolding showed a difference of nearly six orders of magnitude (ΔΔG# = 33.5 kJ·mol−1 at 25 °C) between calcium saturation (at 100 mm CaCl2) and complete removal of calcium ions (in the presence of 100 mm EDTA). Analysis of the protease variant W55F indicated that calcium binding‐site III, situated in the critical region 56–69, determines the stability at calcium ion concentrations between 5 and 50 mm. In the chevron plots the disulfide bridge in G8C/N60C shows a similar effect compared with pWT as the addition of calcium ions, suggesting that the introduced disulfide bridge fixes the region (near calcium binding‐site III) that is responsible for unfolding and subsequent autoproteolysis. Owing to the presence of the disulfide bridge, the ΔΔG# is 13.2 kJ·mol−1 at 25 °C and 5 mm CaCl2. Non‐linear chevron plots reveal an intermediate in unfolding probably caused by local unfolding of the loop 56–69. The occurrence of this intermediate is prevented by calcium concentrations of > 5 mm, or the introduction of the disulfide bridge G8C/N60C.
Self-regulated active galactic nuclei heating in elliptical galaxies
Authors: Kawata D. , Gibson B. K.
Published: March 2005

We study the effect of active galactic nuclei (AGN) heating on the chemodynamical evolution of elliptical galaxies and their X-ray and optical properties using high-resolution Λ-dominated cold dark matter cosmological simulations. Our model considers an AGN as being ‘active’ when a convergent gas inflow condition exists within the nucleus of a galaxy; otherwise, the AGN is assumed to remain dormant. This induces a self-regulated activity for the AGN, the result of which leads to a stable hot corona and the suppression of significant late-time star formation – characteristics not encountered in traditional chemodynamical models of ellipticals. These properties of our AGN heating model lead to a system consistent with both the X-ray and optical properties of comparable elliptical galaxies.
A Comparison of Dirichlet and Neumann Wavemakers for the Numerical Generation and Propagation of Nonlinear Long-Crested Surface Waves
Authors: Baddour R. E. , Parsons W.
Published: March 2005

We are studying numerically the problem of generation and propagation of long-crested gravity waves in a tank containing an incompressible inviscid homogeneous fluid initially at rest with a horizontal free surface of finite extent and of infinite depth. A nonorthogonal curvilinear coordinate system, which follows the free surface, is constructed and the full nonlinear kinematic and dynamic free surface boundary conditions are utilized in the algorithm. “Wavemakers” are modeled using both the Dirichlet and Neumann lateral boundary conditions and a full comparison is given. Overall, the Dirichlet model was more stable than the Neumann model, with an upper limit steepness S=2A/λ of 0.08 using good resolution compared with the Neumann’s maximum of 0.05.
Through-Thickness Properties of TMCP Steels
Authors: Salama Mamdouh M.
Published: March 2005

Two failure modes were observed in tensile test specimens machined from TMCP steel pipe. Longitudinal centerline cracks were formed after necking followed by the conventional cup and cone transverse failure. The formation of the longitudinal cracks was attributed to sulfur segregation and grain growth at the centerline. This gave rise to concerns that TMCP steels might exhibit low through-thickness ductility that could lead to lamellar tear failures in highly constrained joints or joints with through-thickness loadings such as in the case of tubular joints and lifting lugs. It also gave rise to a concern regarding the potential of hydrogen-induced cracking in TMCP steel vessels, pipelines, and cathodically protected tubular joints. The results of through-thickness tensile tests showed that this TMCP steel has good through-thickness ductility in spite of the presence of high sulfur segregation at the centerline. However, the results of slow strain tests on a hydrogen charged through-thickness tensile specimen showed some deterioration in ductility. In addition, the fracture of the specimen was characterized by the presence of multiple circumferential cracks that are characteristic of hydrogen embrittled materials.
Optical properties and microstructure of plasma deposited Ta2O5 and Nb2O5 films
Authors: Szymanowski H. , Zabeida O. , Klemberg-Sapieha J. E. , Martinu L.
Published: March 2005

Advanced optical filter applications require an appropriate control of the optical constants, as well as of other suitable film properties such as mechanical performance, thermal and environmental stability, absence of refractive index inhomogeneities, and others. In the present work we studied the characteristics of two high index optical materials, namely amorphous tantalum pentoxide (Ta2O5) and niobium pentoxide (Nb2O5) prepared by plasma enhanced chemical vapor deposition, using penta-ethoxy tantalum Ta(OC2H5)5 and penta-ethoxy niobium, Nb(OC2H5)5, precursors. We particularly investigated the effect of energetic conditions on the film growth by using different modes of plasma excitation, namely rf, microwave, and dual-mode microwave/radio frequency discharges. Under sufficient ion bombardment, controlled by the rf-induced negative substrate bias, the dense Ta2O5 and Nb2O5 films exhibited a refractive index of 2.16 and 2.26 (at 550nm), respectively, while the extinction coefficient was below 10−5, as determined by spectroscopic ellipsometry, and spectrophotometry. We found that increasing ion bombardment during the film growth leads to an appreciable increase of carbon concentration, as indicated by a strong double peak at 1400 and 1500cm−1 in the Fourier transform infrared spectra. Elastic recoil detection measurements revealed an atomic concentration of 2.5% and 5.5% of carbon in the bulk of the Ta2O5 and Nb2O5 films. The presence of carbon did not appear to negatively affect the film optical and mechanical performance and stability. We discuss the relationship between the optical properties and microstructure, and the possible mechanism of carbon bonding in the form of chelate and bridging groups.
Target material pathways model for high power pulsed magnetron sputtering
Authors: Christie D. J.
Published: March 2005

The potential of high power pulsed magnetron sputtering (HPPMS) has created growing interest, because it can generate a dense plasma with high target material ion content. However, reported deposition rates are significantly lower than for dc or midfrequency ac sputtering at the same average power in most cases. The fraction of target material arriving at the workpiece, which is ionized, ranges from 5% to 70% as reported so far by workers in the field, even though optical emission spectroscopy suggests a highly metallic plasma. A simple pathways model has been developed to explain these experimental results. In addition, evaluation of the model for various interesting materials suggests target material characteristics which are desirable in order to achieve higher deposition rates and a greater ionized fraction of target material reaching the substrate. The model will be presented, with representative characteristic results and implications on HPPMS processes. In addition, insights from approximate model equations will be presented.
Navier–Stokes modeling of a Gaede pump stage in the viscous and transitional flow regimes using slip-flow boundary conditions
Authors: Giors S. , Subba F. , Zanino R.
Published: March 2005

A three-dimensional model for a Gaede pump, based on the Navier–Stokes equations with no-slip boundary conditions, was introduced by the authors in a previous work. A commercial computational fluid dynamics code was used to obtain the solution in an outlet pressure range corresponding to the viscous laminar regime and incipient transition to molecular flow and the validation against the experimental data showed a good level of accuracy in terms of compression ratio. However, the mechanical power dissipation predicted by the no-slip model shows a trend diverging from the measured data for decreasing pressure, in the transitional flow regime. As most of the mechanical power is dissipated into heat by viscosity, slip-flow boundary conditions are introduced here in order to model the transitional effects on the wall shear stress and improve the accuracy of the Navier–Stokes description at low pressure. The calculation is carried out up to Knudsen numbers Kn≈1, showing a very good agreement of the Navier–Stokes model, even close to molecular flow conditions, and leaving a residual error acceptable for design purposes. The model is used to analyze the flow fields in the Gaede pump and explain its behavior. The slip model needs just one adjusting parameter, i.e., the momentum accommodation coefficient, but exhibits a small sensitivity to its variations. Hence it can predict the compression ratio and power dissipation of Gaede pumps of any size in their whole operating pressure range, from the laminar viscous regime down to the transition to the molecular flow regime.
Specific Inhibitory Action of Anisodamine against a Staphylococcal Superantigenic Toxin, Toxic Shock Syndrome Toxin 1 (TSST-1), Leading to Down-Regulation of Cytokine Production and Blocking of TSST-1 Toxicity in Mice
Authors: Nakagawa Saori , Kushiya Koji , Taneike Ikue , Imanishi Ken'ichi , Uchiyama Takehiko , Yamamoto Tatsuo
Published: March 2005

Toxic shock syndrome toxin 1 (TSST-1), produced byStaphylococcus aureus(including methicillin-resistantS. aureus), is a superantigenic toxin responsible for toxic shock syndrome as well as neonatal TSS-like exanthematous disease. TSST-1 exhibits its deleterious effects by leading to the abnormal proliferation of, e.g., Vβ2+T cells and overproduction of proinflammatory cytokines. In the present study we examined the inhibitory effect of a Chinese herbal extract, anisodamine, on TSST-1 using human peripheral blood mononuclear cells (PBMCs). Anisodamine inhibited the production of proinflammatory cytokines better than interleukin-10 (an anti-inflammatory cytokine). The inhibitory effect of anisodamine was greater than that of any tropane alkaloid examined. Anisodamine acted directly on both monocytes and T cells in human PBMCs, and the effect was confirmed at the transcriptional level. Inhibition of NF-κB activation was also demonstrated. In contrast, no significant inhibition of Vβ2+T-cell proliferation was observed. In mice injected with TSST-1, anisodamine treatment significantly decreased serum proinflammatory cytokine levels and prevented TSST-1-induced death. These results suggest that anisodamine specifically acts against the production of cytokines (inflammatory cytokines in particular) and not against Vβ2+T-cell proliferation and that anisodamine may have a beneficial effect on TSST-1-associated disease.
Interleukin-18 Primes the Oxidative Burst of Neutrophils in Response to Formyl-Peptides: Role of Cytochrome b558 Translocation and N-Formyl Peptide Receptor Endocytosis
Authors: Elbim Carole , Guichard Cécile , Dang Pham M. C. , Fay Michèle , Pedruzzi Eric , Demur Hélène , Pouzet Cécile , El Benna Jamel , Gougerot-Pocidalo Marie-Anne
Published: March 2005

Using flow cytometry, we observed that interleukin-18 (IL-18) primed human neutrophils (PMNs) in whole blood to produce superoxide anion (O2°−) in response to N-formyl peptide (fMLP) stimulation, whereas IL-18 alone had no significant effect. In contrast to tumor necrosis factor alpha (TNF-α), which is a cytokine known to strongly prime O2°−production, IL-18 did not induce either p47phoxphosphorylation or its translocation from the cytosol to the plasma membrane. However, IL-18 increased PMN degranulation, as shown by increased levels of cytochrome b558 and CD11b expression at the PMN surface. Moreover, addition of IL-18 to whole blood for 45 min reduced the ability of PMNs to bind to fMLP, suggesting endocytosis of fMLP receptors, as visualized by confocal microscopy. 2,3-Butanedione 2-monoxime, which inhibits endosomal recycling of plasma membrane components back to the cell surface, concomitantly accentuated the diminution of fMLP binding at the PMN surface and increased IL-18 priming of O2°−production by PMNs in response to fMLP. This suggests that fMLP receptor endocytosis could account, at least in part, for the priming of O2°−production. In addition, genistein, a tyrosine kinase inhibitor, and SB203580, a p38 mitogen-activated protein kinase (p38MAPK) inhibitor, completely reversed the decreased level of fMLP binding and increased the level of CD11b expression after IL-18 treatment. Flow cytometric analysis of intact PMNs in whole blood showed that IL-18 increased p38MAPK phosphorylation and tyrosine phosphorylation. In particular, IL-18 induced phosphorylation of focal adhesion kinase (p125FAK), which has been implicated in cytoskeleton reorganization. Taken together, our findings suggest several mechanisms that are likely to regulate cytokine-induced priming of the oxidative burst in PMNs in their blood environment.
Impaired Accessory Cell Function in a Human Dendritic Cell Line after Human Immunodeficiency Virus Infection
Authors: Beuria Prarthana , Chen Houchu , Timoney Michael , Sperber Kirk
Published: March 2005

We generated human dendritic cell (DC) hybridoma cell lines by fusing HGPRT-deficient promonocytic U937 cells with immature DCs obtained by culturing peripheral blood monocytes with interleukin-4 (IL-4; 1,000 U/ml) and granulocyte-macrophage colony-stimulating factor (100 U/ml) for 7 days and mature DCs by treatment with tumor necrosis factor alpha (12.5 μg/ml) for 3 days. Only one fusion with immature DCs was successful and yielded four cell lines—HB-1, HB-2, HB-3, and HB-9—with an overall fusion efficiency of 0.0015%. The cell lines were stable in long-term culture, displayed morphological features typical of DCs, and expressed distinct class I and class II molecules not present on U937 (A*031012, B*51011, Cw*0701, DRB3*01011 52, and DR5*01011). A representative cell line, HB-2, that expressed DC markers including CD83, CD80 and CD86 could be induced to produce IL-12 through CD40 stimulation. After human immunodeficiency virus (HIV) infection, there was impairment of antigen-presenting cell (APC) function, which was manifested by an inability to stimulate allogeneic T-cell responses. There was no change in expression of major histocompatibility complex class I and class II antigens, CD83, CD40, CD4, CD11c, CD80, CD86, CD54, and CD58, or IL-12 production in the HIV-infected HB-2 cells. The HIV-infected HB-2 cells induced T-cell apoptosis in the cocultures. T-cell proliferation could be partially restored by using ddI, indinivir, and blocking anti-gp120 and anti-IL-10 antibodies. Our data suggest that there are multiple mechanisms that DCs use to inhibit T-cell responses in HIV-infected patients. The HB-2 cell line could be a useful model system to study APC function in HIV-infected DCs.
Use of the COOH Portion of the Nucleocapsid Protein in an Antigen-Capturing Enzyme-Linked Immunosorbent Assay for Specific and Sensitive Detection of Severe Acute Respiratory Syndrome Coronavirus
Authors: Qiu Maofeng , Wang Jin , Wang Hongxia , Chen Zeliang , Dai Erhei , Guo Zhaobiao , Wang Xiaoyi , Pang Xin , Fan Baoxing , Wen Jie , Wang Jian , Yang Ruifu
Published: March 2005

Antibody detection with a recombinant COOH portion of the severe acute respiratory syndrome (SARS) coronavirus nucleocapsid (N) protein, N13 (amino acids 221 to 422), was demonstrated to be more specific and sensitive than that with the full-length N protein, and an N13-based antigen-capturing enzyme-linked immunosorbent assay providing a convenient and specific test for serodiagnosis and epidemiological study of SARS was developed.
The timing of spawning migration: implications of environmental variation, life history, and sex
Authors: Dahl Jonas , Dannewitz Johan , Karlsson Lars , Petersson Erik , Löf Anna , Ragnarsson Bjarne
Published: March 2005

During 1960–2002, the arrival times of all spawning male and female Atlantic salmon (Salmo salar L., 1758) and brown trout (Salmo trutta L., 1758) entering Dalälven River were recorded. To study the role of environmental variation in spawning migration timing, we used long-term temperature (river and sea) and river discharge data. For salmon, the spawning migration peak was strongly correlated with mean monthly sea and river temperatures during spring: salmon arrived earlier when temperatures were higher and later when temperatures were lower. River discharge explained little of the variation in migration timing. Female salmon migration showed a stronger correlation with temperature than male salmon migration, and female salmon arrived ≈18 days earlier than males. Trout showed a larger variation in their spawning migration, but river and sea temperatures and river discharge explained little of the variation. Trout females arrived ≈7 days earlier than males. The sea and river temperatures were highly correlated during the spawning migration, indicating that large climate processes determine the temperature regimes in the Baltic Sea and its tributaries. Time of arrival at the river was not correlated with ovulation date; a female salmon or brown trout arriving late could ovulate almost immediately, whereas a female arriving early could wait to ovulate.
Physical factors affecting the relative abundance of native and invasive amphipods in the St. Lawrence River
Authors: Palmer M E , Ricciardi A
Published: March 2005

The Ponto-Caspian amphipod Echinogammarus ischnus (Stebbing, 1899) is reportedly replacing the North American amphipod Gammarus fasciatus Say, 1818, in the lower Great Lakes, but the two species appear to coexist in the upper St. Lawrence River several years after invasion by E. ischnus. A multi-site survey in the river between Lake Ontario and Montreal (Quebec) found that E. ischnus and G. fasciatus respond differently to substrate characteristics, water chemistry variables, and current velocity. Both species increase in abundance in the presence of dreissenid mussels. However, E. ischnus density is positively correlated with current velocity and an increasing proportion of gravel-sized sediment, while G. fasciatus density is positively correlated with benthic filamentous algal (Cladophora spp.) biomass, macrophyte biomass, and pH. Habitat heterogeneity within the river may be promoting the coexistence of native and exotic amphipods by allowing them to segregate along physicochemical gradients.
Reproductive life-span and sources of mortality for alternative male life-history strategies in sockeye salmon,Oncorhynchus nerka
Authors: Carlson Stephanie M , Rich, Jr. Harry B , Quinn Thomas P
Published: March 2005

In anadromous salmonid fishes, a fraction of the males ("jacks") spend fewer years at sea than females and most males in the population. It has been hypothesized that the higher survival rates of jacks at sea are balanced by their reduced reproductive success. One component of reproductive success is in-stream longevity, and jacks were reported to have a shorter reproductive life-span than older males. To test this hypothesis, we examined the interactions between arrival date, mode of death (senescent, bear-killed, gull-killed, stranded), and reproductive life-span of male sockeye salmon, Oncorhynchus nerka (Walbaum in Artedi, 1792), in a small Alaskan creek. Of the senescent males, early-arriving fish lived longer than later arrivals, and jacks and older males had similar reproductive life-spans (p = 0.932). Jacks were less susceptible to premature mortality (mostly from bears and gulls) than older males. The life-span of fish that died prematurely was greater for jacks than non-jacks (p < 0.001). Considering all sources of mortality (both premature and senescent), jacks had a greater mean life-span than older males (5.84 vs. 3.12 days; p < 0.001). Despite this fact, jacks are scarce (1.7% in this population), suggesting that they suffer in other components of fitness such as proportion of eggs fertilized.
Edge effects on nest predators in two forested landscapes
Authors: Smith Michelle L
Published: March 2005

Few studies have systematically examined edge effects on nest predators, although many invoke these processes as potential mechanisms for decreased nesting success of songbirds. Species richness and relative abundance of avian and mammalian nest predators were compared between forest edge and interior in two landscapes, Allegan State Game Area and Fort Custer Training Center (FCTC), in southwest Michigan. One avian predator, the American crow (Corvus brachyrhynchos Brehm, 1822), was more abundant at edges than forest interior at FCTC; however, other predators did not demonstrate an edge response. Abundance of the brood parasite (Molothrus ater (Boddaert, 1783)) was greater at edges in FCTC. Overall abundance was higher at FCTC in both years; however, this could not be attributed to a greater extent of fragmentation. Total species richness for both landscapes did not differ between edge and interior. Remote-camera systems captured three predation events, two involving red squirrels (Tamiasciurus hudsonicus (Erxleben, 1777)) and one involving a blue jay (Cyanocitta cristata (L., 1758)). Vegetation characteristics were similar between edge and interior sites, which suggests that vegetation structure did not influence edge response. The variability in response indicates a need to assess patterns of predator distributions through long-term studies at multiple spatial scales.
Partitioning of diving effort in foraging trips of northern gannets
Authors: Lewis Sue , Benvenuti Silvano , Daunt Francis , Wanless Sarah , Dall'Antonia Luigi , Luschi Paolo , Elston David A , Hamer Keith C , Sherratt Thomas N
Published: March 2005

Many species of seabirds are known to undertake foraging trips that vary in duration, lasting from a few hours up to several days. However, the important question of how individuals allocate their time during foraging trips of different durations has received relatively little attention until recently. Using activity loggers, we examined the foraging behavior of chick-rearing northern gannets, Morus bassanus (L., 1758), during trips of different durations, and tested predictions concerning how foraging activity varies across trips. There was no evidence of a relationship between dive frequency during the first 3 h of a trip and trip duration, suggesting that the decision to continue on a longer trip was not affected by an adult's initial rate of encounter with prey. Flight constituted approximately 50% of total trip time, and the dive rate of birds per daylight hour was apparently unaffected by trip duration. Birds dived at similar rates on the outward and return sections of their foraging trips, which suggests that they may have been "topping up" on food on their return. Overall our results suggest that, unlike other pelagic seabirds, northern gannets at the Bass Rock do not adjust their individual foraging strategies among trips of different durations.