bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic resonance imaging methods to reveal the real‐time distribution of nickel in porous media
Authors: Moradi A. B. , Oswald S. E. , Massner J. A. , Pruessmann K. P. , Robinson B. H. , Schulin R. 
Published: January 2008

SummaryDirect and non‐destructive measurement of the sorption, diffusion and mobility of ions and molecules in porous media has applications in industry and environmental science. We used magnetic resonance imaging (MRI) to visualize the dynamic distribution of paramagnetic nickel (Ni+2) ions in porous media. Various MRI sequences were tested to image Ni2+ at small concentrations. Noisy gradient echo images had poor contrast between samples containing various Ni2+ concentrations. Turbo spin echo and spoiled gradient echo images showed a linear relation between Ni2+ concentrations and signal intensity over a wide range of concentrations. Spoiled gradient echo images resolved Ni2+ concentrations (down to 30 mg litre−1) better than turbo spin echo images. However, for smaller concentrations, uncertainty in intensity values increased. A T1 measurement, obtained using an inversion recovery sequence, showed a linear correlation between T1 and Ni2+ concentration down to 1.5 mg litre−1. In a glass bead medium with an ion exchange resin as an Ni sink, the real‐time development of the Ni2+ depletion zone around the resin, as Ni was sorbed into the resin, was imaged by T1 mapping. A spatial resolution of 0.58 mm and a temporal resolution of less than a minute were achieved. The two‐dimensional Ni2+ gradient that was determined from MRI agreed well with geochemical modelling results. The results of this study showed that MRI, in particular T1 mapping, can quantify microscale behaviour of paramagnetic species in porous media. However, ferromagnetic components that naturally occur in most soils can easily disturb the MRI signal.
Modelling soil temperatures in northern peatlands
Authors: Kettridge N. , Baird A. 
Published: January 2008

SummaryMethane emissions from northern peatlands are strongly dependent on soil temperatures. Therefore, to predict methane emissions from northern peatlands under future climatic conditions, it is important to simulate the effect of these changing climatic conditions on peat temperatures. This article reports on the development and testing of two one‐dimensional (1D) models used to simulate soil temperatures at shallow depths in a northern peatland. First, the HIP‐Dlet (Heat in Peat – Dirichlet) model applies measured temperatures to the surface boundary of a conduction‐based temperature model. Secondly, the HIP‐Nmann (Heat in Peat – von Neumann) model simulates the surface boundary from standard meteorological measurements. The HIP‐Dlet model provides a reasonable to good approximation of measured temperatures showing that heat transport processes within the soil are adequately simulated. The model does not simulate an advective liquid heat flux. However, only substantial rainfall events (> 70 mm over 3 days) during the study period had any significant effect on model error. Errors in the HIP‐Nmann model were of a similar magnitude to the HIP‐Dlet model. Errors in the HIP‐Dlet model resulted predominantly from errors in the measured soil temperatures. Errors in the HIP‐Nmann were due to errors in the measured soil temperatures and the inaccurate simulation of the surface boundary condition. The development of future peatland temperature models should, therefore, focus on the simulation of the surface boundary condition, particularly the parameterisation of the surface resistance that is shown here to produce significant errors in the modelled soil temperatures.
Spatial scale affects bioclimate model projections of climate change impacts on mountain plants
Authors: TRIVEDI MANDAR R. , BERRY PAMELA M. , MORECROFT MICHAEL D. , DAWSON TERENCE P. 
Published: January 2008

AbstractPlant species have responded to recent increases in global temperatures by shifting their geographical ranges poleward and to higher altitudes. Bioclimate models project future range contractions of montane species as suitable climate space shifts uphill. The species–climate relationships underlying such models are calibrated using data at either ‘macro’ scales (coarse resolution, e.g. 50 km × 50 km, and large spatial extent) or ‘local’ scales (fine resolution, e.g. 50 m × 50 m, and small spatial extent), but the two approaches have not been compared. This study projected macro (European) and local models for vascular plants at a mountain range in Scotland, UK, under low (+1.7 °C) and high (+3.3 °C) climate change scenarios for the 2080s. Depending on scenario, the local models projected that seven or eight out of 10 focal montane species would lose all suitable climate space at the site. However, the European models projected such a loss for only one species. The cause of this divergence was investigated by cross‐scale comparisons of estimated temperatures at montane species' warm range edges. The results indicate that European models overestimated species' thermal tolerances because the input coarse resolution climate data were biased against the cold, high‐altitude habitats of montane plants. Although tests at other mountain ranges are required, these results indicate that recent large‐scale modelling studies may have overestimated montane species' ability to cope with increasing temperatures, thereby underestimating the potential impacts of climate change. Furthermore, the results suggest that montane species persistence in microclimatic refugia might not be as widespread as previously speculated.
Scaling environmental change through the community‐level: a trait‐based response‐and‐effect framework for plants
Authors: SUDING KATHARINE N. , LAVOREL SANDRA , CHAPIN F. S. , CORNELISSEN JOHANNES H. C. , DÍAZ SANDRA , GARNIER ERIC , GOLDBERG DEBORAH , HOOPER DAVID U. , JACKSON STEPHEN T. , NAVAS MARIE‐LAURE 
Published: January 2008

AbstractPredicting ecosystem responses to global change is a major challenge in ecology. A critical step in that challenge is to understand how changing environmental conditions influence processes across levels of ecological organization. While direct scaling from individual to ecosystem dynamics can lead to robust and mechanistic predictions, new approaches are needed to appropriately translate questions through the community level. Species invasion, loss, and turnover all necessitate this scaling through community processes, but predicting how such changes may influence ecosystem function is notoriously difficult. We suggest that community‐level dynamics can be incorporated into scaling predictions using a trait‐based response–effect framework that differentiates the community response to environmental change (predicted by response traits) and the effect of that change on ecosystem processes (predicted by effect traits). We develop a response‐and‐effect functional framework, concentrating on how the relationships among species' response, effect, and abundance can lead to general predictions concerning the magnitude and direction of the influence of environmental change on function. We then detail several key research directions needed to better scale the effects of environmental change through the community level. These include (1) effect and response trait characterization, (2) linkages between response‐and‐effect traits, (3) the importance of species interactions on trait expression, and (4) incorporation of feedbacks across multiple temporal scales. Increasing rates of extinction and invasion that are modifying communities worldwide make such a research agenda imperative.
Warming prevents the elevated CO2‐induced reduction in available soil nitrogen in a temperate, perennial grassland
Authors: HOVENDEN MARK J. , NEWTON P. C. D. , CARRAN R. A. , THEOBALD P. , WILLS K. E. , VANDER SCHOOR J. K. , WILLIAMS A. L. , OSANAI Y. 
Published: January 2008

AbstractRising atmospheric carbon dioxide concentration ([CO2]) has the potential to stimulate ecosystem productivity and sink strength, reducing the effects of carbon (C) emissions on climate. In terrestrial ecosystems, increasing [CO2] can reduce soil nitrogen (N) availability to plants, preventing the stimulation of ecosystem C assimilation; a process known as progressive N limitation. Using ion exchange membranes to assess the availability of dissolved organic N, ammonium and nitrate, we found that CO2 enrichment in an Australian, temperate, perennial grassland did not increase plant productivity, but did reduce soil N availability, mostly by reducing nitrate availability. Importantly, the addition of 2 °C warming prevented this effect while warming without CO2 enrichment did not significantly affect N availability. These findings indicate that warming could play an important role in the impact of [CO2] on ecosystem N cycling, potentially overturning CO2‐induced effects in some ecosystems.
CD22: an inhibitory enigma
Authors: Walker Jennifer A. , Smith Kenneth G. C. 
Published: January 2008

SummaryCD22 is an inhibitory coreceptor of the B‐cell receptor (BCR), and plays a critical role in establishing signalling thresholds for B‐cell activation. Like other coreceptors, the ability of CD22 to modulate B‐cell signalling is critically dependent upon its proximity to the BCR, and this in turn is governed by the binding of its extracellular domain to α2,6‐linked sialic acid ligands. Manipulation of CD22 ligand binding in various experimental settings has profound effects on B‐cell signalling, but as yet there is no complete model for how ligand binding in vivo controls normal CD22 function. Several elegant studies have recently shed light on this issue, although the results appear to suggest two mutually exclusive models for the role of ligand binding; in either promoting or inhibiting, CD22 function. We shall therefore discuss these results in detail, and suggest possible approaches by which these conflicting experimental findings might be reconciled. We shall also consider a second important issue in CD22 biology, which relates to the role that defects in this receptor might play in mediating autoimmune disease. We review the current evidence for this, and discuss the importance of genetic background in modifying CD22 function and predisposition to autoimmunity.
Hydrogen peroxide induces expression and activation of AMP‐activated protein kinase in a dental pulp cell line
Authors: Fukuyama Y. , Ohta K. , Okoshi R. , Kizaki H. , Nakagawa K. 
Published: January 2008

AbstractAim  To investigate the effects of hydrogen peroxide on cell viability and expression and activation of AMP‐activated protein kinase (AMPK) in rat dental pulp cell line RPC‐C2A.Methodology  RPC‐C2A cells derived from rat dental pulp were maintained in MEM supplemented with 10% FBS at 37 °C, in a humidified atmosphere at 5% CO2. Cells were cultured in the presence or absence of H2O2 for up to 60 min at concentrations of from 0.1 to 3.0 mmol L−1. Cell viability was analysed by WST‐1 reduction assay. Expression of AMPK subunit isoforms was analysed by Western blotting using antibodies to the catalytic α1 and regulatory β1 and γ1 subunit isoforms. The effect of silencing AMPKα1 on cell viability was determined using siRNA.Results  Exposure to H2O2 decreased cell viability in a time‐ and dose‐dependent manner. The catalytic AMPKα1 subunit and its activated form, phospho‐AMPKα, increased with exposure to H2O2 in a time‐ and dose‐dependent manner, whereas the regulatory β1 and γ1 subunits showed no change. Downregulation of AMPKα1 resulted in a reduction in cell viability in H2O2‐treated cells at a concentration of 0.1 mmol L−1 for 30 min incubation, indicating an increased sensitivity to H2O2.Conclusions  Reactive oxygen induced energy fuel gauge enzyme AMPKα expression and its activation by phosphorylation in RPC‐C2A cells, suggesting that AMPK is essential for protection against H2O2‐induced nonapoptotic cell death. Therefore, AMPK may be a therapeutic modulation target for treatment of the dentine–pulp complex injured by reactive oxygen.
Gingival and bone necrosis caused by accidental sodium hypochlorite injection instead of anaesthetic solution
Authors: Pontes F. , Pontes H. , Adachi P. , Rodini C. , Almeida D. , Pinto D. 
Published: January 2008

AbstractAim  To report clinical complications (pain, necrotic gingival tissue and bone sequestration) resulting from accidental injection of sodium hypochlorite.Summary  Root canal treatment is a routine clinical procedure with few reported complications. Sodium hypochlorite (NaOCl) is commonly used as an irrigant during the procedure because of its tissue‐dissolving, antibacterial and lubricating properties. This paper presents a case in which accidental injection of sodium hypochlorite into the lingual gingiva of a female patient caused gingival and bone necrosis. Surgical intervention was required.Key learning points

Sodium hypochlorite is dangerous if injected into the tissues.
The presentation of sodium hypochlorite in glass, anaesthetic type cartridges is potentially dangerous, and should be condemned.
All healthcare workers should check carefully the contents of any syringe before injecting into patients.
Micropush‐out bond strengths of gutta‐percha versus thermoplastic synthetic polymer‐based systems – an ex vivo study
Authors: Üreyen Kaya B. , Keçeci A. D. , Orhan H. , Belli S. 
Published: January 2008

AbstractAim  To compare the interfacial strength and failure mode of root fillings consisting of different technique–material combinations.Methodology  Human mandibular premolars (n = 144) instrumented to apical size 40 and .06 taper were divided into 12 experimental groups. The root canals were filled with either gutta‐percha (groups 1–6) or Resilon (groups 7–12) core materials combined with AH Plus (groups 1, 4, 7, 10), Ketac‐Endo (groups 2, 5, 8, 11) or Epiphany (groups 3, 6, 9, 12) using cold lateral compaction (groups 1–3, groups 7–9) or System B with Obtura II (groups 4–6, groups 10–12).Three serial 1.00 ± 0.05‐mm‐thick root slices were prepared and push‐out tests on the filling material were performed. Interactions amongst the compaction techniques, core materials and sealers were analysed using a three‐way analysis of variance (anova) (P < 0.05). One‐way anova and Duncan’s Multiple Range tests were used to compare the bond strengths of the 12 groups. Fracture modes of all root slices were evaluated stereomicroscopically at ×40 magnification.Results  All the parameters except compaction techniques had significant interactions (P < 0.05). A significant difference was found amongst the groups (P < 0.05). Gutta‐percha/Ketac‐Endo/cold lateral compaction and gutta‐percha/AH Plus/cold lateral compaction groups had the highest micropush‐out bond strength values (P < 0.05). The number of overall cohesive failures was significantly more than that of adhesive failures (P < 0.05).Conclusions  The push‐out bond strengths of Resilon/Epiphany combinations were lower than those of gutta‐percha/conventional root canal sealer combinations. Core materials and sealers may affect the push‐out bond strengths of root canal filling materials.
Root form and canal morphology of mandibular premolars in a Jordanian population
Authors: Awawdeh L. A. , Al‐Qudah A. A. 
Published: January 2008

AbstractAim  To investigate the root canal anatomy of mandibular premolars in a Jordanian population.Methodology  Nine hundred extracted mandibular premolars were examined. After the length of the teeth was measured, the presence of developmental grooves and furcated roots was noted. Following the preparation of access cavities, pulp tissue was removed and the canal systems were stained. The teeth were then rendered clear by demineralization and immersion in methyl salicylate. Cleared teeth were examined and the following features were evaluated: (i) type of root canals; (ii) presence and location of lateral canals; transverse anastomosis; (iii) location of apical foramina; and (iv) frequency of apical deltas.Results  The mean lengths of first and second mandibular premolars were 22.6 mm (18–27.5 mm) and 22.2 mm (16–26.5 mm), respectively. Although the majority of the specimens corresponded to Vertucci’s classification scheme, analysis of this large data set revealed four additional root canal morphologies. Variable root canal morphologies were found in the mandibular first premolars; two separate apical foramina were found in 33% of the teeth with two canals, compared to 6.2% with one apical foramen. Teeth with three separate apical foramina were scarce (2.2%). The majority of the mandibular second premolars had a single canal; 72% of teeth possessed type I canal systems, whilst 22.8% of the roots had two canals with two separate apical foramina.Conclusions  The prevalence of multiple canals in the investigated Jordanian mandibular premolars was high, especially for the second mandibular premolar, in comparison with previous studies performed on populations of different racial origin.
Developmental toxicity of UV filters and environmental exposure: a review
Authors: Schlumpf Margret , Durrer Stefan , Faass Oliver , Ehnes Colin , Fuetsch Michaela , Gaille Catherine , Henseler Manuel , Hofkamp Luke , Maerkel Kirsten , Reolon Sasha , Timms Barry , Tresguerres Jesus A. F. , Lichtensteiger Walter 
Published: January 2008

SummarySeveral ultraviolet (UV) filters exhibit estrogenic, some also anti‐androgenic activity. They are present in waste water treatment plants, surface waters and biosphere including human milk, suggesting potential exposure during development. Developmental toxicity was studied in rats for the UV filters 4‐methylbenzylidene camphor (4‐MBC, 0.7, 7, 24, 47 mg/kg/day) and 3‐benzylidene camphor (3‐BC, 0.07, 0.24, 0.7, 2.4, 7 mg/kg/day) administered in chow to the parent generation before mating, during pregnancy and lactation, and to the offspring until adulthood. Neonates exhibited enhanced prostate growth after 4‐MBC and altered uterine gene expression after both chemicals. 4‐MBC and 3‐BC delayed male puberty and affected reproductive organ weights of adult offspring. Effects on the thyroid axis were also noted. Expression and oestrogen sensitivity of oestrogen‐regulated genes and nuclear receptor coregulator levels were altered at mRNA and protein levels in adult uterus, prostate and brain regions involved in gonadal control and sexual behaviour. Female sexual behaviour was impaired by both filters; 3‐benzylidene camphor caused irregular cycles. Classical endpoints exhibited lowest observed adverse effect levels (LOAELs) and no observed adverse effect levels (NOAELs) of 7/0.7 mg/kg for 4‐MBC and 0.24/0.07 mg/kg for 3‐BC. Molecular endpoints were affected by the lowest doses studied. Our data indicate that the potential risk posed by endocrine active UV filters warrants further investigations.
The effect of pinealectomy and leptin hormone on the proliferation and apoptosis activation in Syrian hamster testis in different photoperiods
Authors: Gündüz Bülent , Karakaş Alper , Terzi Hakan , Öner Jale , Serin Erdinç , Kükner Aysel 
Published: January 2008

SummaryThe effects of pinealectomy and leptin hormone on proliferative and apoptotic processes in the epithelia of testicular seminiferous tubules of Syrian hamsters have been investigated. Proliferative and apoptotic processes were assessed semi‐quantitatively by proliferating cell nuclear antigen (PCNA) and caspase‐3 immune stainings. Animals used in the study were divided into four groups; control, pinealectomy (PinX), leptin‐treated (10 μg/mL/day/kg body weight, intraperitoneally) and pinealectomy + leptin groups. Half of the hamsters in each group were exposed to short and the other half to long photoperiods for 8 weeks. In short photoperiod, PCNA activity especially in spermatogonia was significantly higher in the pinealectomy and leptin‐treated groups compared with the control group. Histological score (HSCORE) value of PCNA in the PinX + leptin group was lower than those of PinX and leptin‐treated groups. HSCORE value of caspase‐3 in PinX and PinX + leptin groups was increased. In the long photoperiod, PCNA activation in the PinX group was significantly lower than the control group while the differences between the controls and other groups were not significant. The difference between the increases in caspase‐3 activity in the PinX and control groups was significant. Thus, it was observed that photoperiods had no effect on the proliferation activity in the control groups. The inhibiting effect of short photoperiod on testis was not observed throughout 8 weeks. PinX eliminated the inhibiting effect of short photoperiod but did not alter the stimulating effect of long photoperiod. Leptin did not show any effect in long photoperiod but decreased proliferation by stimulating melatonin in short photoperiod.
ORIGINAL ARTICLE: Origins of Bradyrhizobium nodule symbionts from two legume trees in the Philippines
Authors: Andam Cheryl P. , Parker Matthew A. 
Published: January 2008

AbstractAim  Geographic affinities were analysed for nodule bacteria (Bradyrhizobium sp. Jordan) associated with two legume trees indigenous to the Philippines: Pterocarpus indicus (Papilionoideae) and Wallaceodendron celebicum (Mimosoideae).Location  Nodule bacteria from Luzon, the Philippines, were compared with reference strains from Central America, eastern North America, Japan, Korea, China and Australia.Methods  Two PCR assays targetting length polymorphisms in the rRNA region were carried out on 96 Philippine bacterial isolates. A 496‐bp portion of the 23S rRNA gene was sequenced in 14 representative isolates. Eight strains were analysed in greater depth by sequencing portions of four other genes (16S rRNA [1410 bp], dnaK [603 bp], nifD [822 bp], recA [512 bp]), and phylogenetic trees were constructed by maximum parsimony, neighbour joining and maximum likelihood methods.Results  Most of the Philippine Bradyrhizobium strains showed greater similarity to reference strains from Central America than to strains from other source regions included in the analysis. However, phylogenetic trees for the five genes had significantly conflicting topologies, suggesting that lateral gene transfer events had altered genealogical relationships at different loci. In particular, two Philippine strains resembled Bradyrhizobium strains from Central America or China for 16S rRNA, dnaK and recA sequences, but had nifD sequences that clustered with Australian strains (with bootstrap support values of 90–96%).Main conclusions  The Philippines have been colonized by Bradyrhizobium strains from multiple source regions. Subsequent lateral gene transfer has resulted in the evolution of Bradyrhizobium strains that combine DNA segments of different geographic origin.