bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of water‐extractable copper in soil with time as a function of organic matter amendments and aeration
Authors: Wang G. , Staunton S. 
Published: September 2005

SummaryVariations in soil conditions can influence the speciation and hence availability of copper. We have followed the evolution of water‐extractability of both native and added copper in a clay‐loam topsoil over 5 months. The effects of addition of organic amendments, either leaf compost or lucerne straw, were studied. Soils were incubated under controlled conditions either moist and well‐aerated, or flooded. Other chemical properties were monitored (pH, redox potential, water‐extractable organic carbon, iron and manganese). Freshly added Cu was initially more soluble than native Cu, but the contrast decreased with time. Solubility was greater in flooded soils than in aerated samples. Solubility also increased with increasing pH, contrary to often‐reported trends. Although the extractability of added Cu increased with increasing dissolved organic carbon, as expected from the formation of complexes in solution, that of native soil Cu did not. Large, short‐lived flushes of Cu were associated with flushes of dissolved organic matter, particularly from decomposition of lucerne straw, but these relations were not always statistically significant when the entire data set was considered. The total amount of dissolved organic carbon is not a sufficiently sensitive probe to assess the extent to which Cu is solubilized by the formation of complexes in soil solution. The changing composition of soil and soil solution during incubation led to 10‐fold differences in the proportion of Cu that was water‐extractable. Single measurements of extractability can therefore never give an accurate estimation of mobility and availability of copper in soil.
Total and soluble fluorine concentrations in relation to properties of soils in New Zealand
Authors: Loganathan P. , Gray C. W. , Hedley M. J. , Roberts A. H. C. 
Published: September 2005

SummarySoil fluorine (F) concentrations continue to increase in agricultural soils receiving regular applications of phosphatic fertilizer. Continued accumulation of soil F poses a risk to grazing ruminants and may pose a future risk to groundwater quality. This paper examines the range of total F (Ft) concentrations and forms of soluble F species and their relationship to selected soil properties in New Zealand agricultural soils. The Ftand soluble F (soil F extracted with water (Fwater) and 0.01 mKCl (FKCl)) concentrations in 27 soil samples (0–75 mm depth) taken from predominantly pasture sites in the North and South Islands of New Zealand were much less than those reported in the literature for sites contaminated with F from industry. The Ftconcentrations ranged from 212 to 617 µg F g−1soil. The F‐toxicity risk to grazing animals in farms at these sites through soil ingestion is small at present, but farms with very large Ftconcentrations (i.e. > 500 µg F g−1) need to adopt suitable grazing and fertilizer management practices to avoid future F‐toxicity risk. The Ftconcentration had very strong positive correlations with both total soil P and total soil Cd concentrations, reflecting the link between P fertilizer use and F accumulation in the soils. It also had significant positive correlations with organic matter and amorphous Al oxides contents, indicating that F is strongly bound to Al polymers adsorbed to organic matter and amorphous Al oxides. The Fwaterand FKClconcentrations and free F–ion concentrations in water (F–water) and 0.01 mKCl (F–KCl) extracts were generally two and three orders of magnitude, respectively, less than the Ftconcentrations and were much less than the concentrations considered phytotoxic. The Fwaterand FKClconcentrations were positively related to soil organic matter content and negatively related to soil pH. Regression models relating Fwaterand FKClconcentrations to soil organic matter content and soil pH suggest that F can be very soluble in extremely acidic soils (pH(water) < 4.9) with large organic matter contents and therefore F potentially may contaminate groundwater if these soils are also coarse‐textured and the water table is shallow.
Estimating the contribution of leaf litter decomposition to soil CO2efflux in a beech forest using13C‐depleted litter
Authors: Ngao Jérôme , Epron Daniel , Brechet Claude , Granier André 
Published: September 2005

AbstractThe contribution of leaf litter decomposition to total soil CO2efflux (FL/F) was evaluated in a beech (Fagus sylvaticaL.) forest in eastern France. The Keeling‐plot approach was applied to estimate the isotopic composition of respired soil CO2from soil covered with either control (−30.32‰) or13C‐depleted leaf litter (−49.96‰). Theδ13C of respired soil CO2ranged from −25.50‰ to −22.60‰ and from −24.95‰ to −20.77‰, respectively, with depleted or control litter above the soil. TheFL/Fratio was calculated by a single isotope linear mixing model based on mass conservation equations. It showed seasonal variations, increasing from 2.8% in early spring to about 11.4% in mid summer, and decreasing to 4.2% just after leaf fall. Between December 2001 and December 2002, cumulatedFandFLreached 0.98 and 0.08 kgC m−2, respectively. On an annual basis, decomposition of fresh leaf litter accounted for 8% of soil respiration and 80% of total C loss from fresh leaf litter. The other fraction of carbon loss during leaf litter decomposition that is assumed to have entered the soil organic matter pool (i.e. 20%) represents only 0.02 kgC m−2.
Alterations in the production and concentration of selected alkaloids as a function of rising atmospheric carbon dioxide and air temperature: implications for ethno‐pharmacology
Authors: Ziska L. H. , Emche S. D. , Johnson E. L. , George K. , Reed D. R. , Sicher R. C. 
Published: September 2005

AbstractThe influence of recent and projected changes in atmospheric carbon dioxide concentration [CO2] with and without concurrent increases in air temperature was determined with respect to growth characteristics and production of secondary compounds (alkaloids) in tobacco (Nicotiana tabacum L.) and jimson weed (Datura stramonium L.) over a ca. 50‐day period. Rising [CO2] above that present at the beginning of the 20th century resulted in consistent, significant increases in leaf area, and above ground dry weight (both species), but decreased leaf area ratio (LAR) and specific leaf area (SLA) in jimson weed. Increased temperature resulted in earlier development and increased leaf area for both species, but increases in above ground final dry weight were observed only for jimson weed. The secondary compounds evaluated included the alkaloids, nicotine, atropine and scopolamine. These compounds are generally recognized as having impacts with respect to herbivory as well as human physiology. Rising [CO2] reduced the concentration of nicotine in tobacco; but had no effect on atropine, and increased the concentration of scopolamine in jimson weed. However, because of the stimulatory effect of [CO2] on growth, the amount of all three secondary compounds increased on a per plant basis in both species. Temperature per se had no effect on nicotine or scopolamine concentration, but significantly increased the concentration and amounts of atropine per plant. Overall, the underlying mechanism of CO2 induced changes in secondary compounds remains unclear; however, these data suggest that the increase in [CO2] and temperature associated with global climate change may have significant effects not only with respect to herbivory, but on the production of secondary compounds of pharmacological impact.
Impacts of an anomalously warm year on soil CO2 efflux in experimentally manipulated tallgrass prairie ecosystems
Authors: Verburg Paul S. J. , Larsen Jessica , Johnson Dale W. , Schorran David E. , Arnone John A. 
Published: September 2005

AbstractModeling analyses suggest that an increase in growth rate of atmospheric CO2 concentrations during an anomalously warm year may be caused by a decrease in net ecosystem production (NEP) in response to increased heterotrophic respiration (Rh). To test this hypothesis, 12 intact soil monoliths were excavated from a tallgrass prairie site near Purcell, Oklahoma, USA and divided among four large dynamic flux chambers (Ecologically Controlled Enclosed Lysimeter Laboratories (EcoCELLs)). During the first year, all four EcoCELLs were subjected to Oklahoma air temperatures. During the second year, air temperature in two EcoCELLs was increased by 4°C throughout the year to simulate anomalously warm conditions. This paper reports on the effect of warming on soil CO2 efflux, representing the sum of autotrophic respiration (Ra) and Rh.During the pretreatment year, weekly average soil CO2 efflux was similar in all EcoCELLs. During the late spring, summer and early fall of the treatment year, however, soil CO2 efflux was significantly lower in the warmed EcoCELLs. In general, soil CO2 efflux was correlated with soil temperature and to a lesser extent with moisture. A combined temperature and moisture regression explained 64% of the observed variation in soil CO2 efflux. Soil CO2 efflux correlated well with a net primary production (NPP) weighted greenness index derived from digital photographs. Although separate relationships for control and warmed EcoCELLs showed better correlations, one single relationship explained close to 70% of the variation in soil CO2 efflux across treatments and years. A strong correlation between soil CO2 efflux and canopy development and the lack of initial response to warming indicate that soil CO2 efflux is dominated by Ra. This study showed that a decrease in soil CO2 efflux in response to a warm year was most likely dominated by a decrease in Ra instead of an increase in Rh.
Estimating annual N2O emissions from agricultural soils in temperate climates
Authors: Roelandt Caroline , Van Wesemael Bas , Rounsevell Mark 
Published: September 2005

AbstractThe Kyoto protocol requires countries to provide national inventories for a list of greenhouse gases including N2O. A standard methodology proposed by the Intergovernmental Panel on Climate Change (IPCC) estimates direct N2O emissions from soils as a constant fraction (1.25%) of the nitrogen input. This approach is insensitive to environmental variability. A more dynamic approach is needed to establish reliable N2O emission inventories and to propose efficient mitigation strategies. The objective of this paper is to develop a model that allows the spatial and temporal variation in environmental conditions to be taken into account in national inventories of direct N2O emissions. Observed annual N2O emission rates are used to establish statistical relationships between N2O emissions, seasonal climate and nitrogen‐fertilization rate. Two empirical models, MCROPS and MGRASS, were developed for croplands and grasslands. Validated with an independent data set, MCROPS shows that spring temperature and summer precipitation explain 35% of the variance in annual N2O emissions from croplands. In MGRASS, nitrogen‐fertilization rate and winter temperature explain 48% of the variance in annual N2O emissions from grasslands. Using long‐term climate observations (1900–2000), the sensitivity of the models with climate variability is estimated by comparing the year‐to‐year prediction of the model to the precision obtained during the validation process. MCROPS is able to capture interannual variability of N2O emissions from croplands. However, grassland emissions show very small interannual variations, which are too small to be detectable by MGRASS. MCROPS and MGRASS improve the statistical reliability of direct N2O emissions compared with the IPCC default methodology. Furthermore, the models can be used to estimate the effects of interannual variation in climate, climate change on direct N2O emissions from soils at the regional scale.
Calcium release and pH‐characteristics of calcium hydroxide plus points
Authors: Lohbauer U. , Gambarini G. , Ebert J. , Dasch W. , Petschelt A. 
Published: September 2005

AbstractAim  To evaluate calcium ion release and pH‐characteristics of calcium hydroxide plus points (CHPP), conventional calcium hydroxide points (CHP, both Coltène/Whaledent, Langenau, Germany) and aqueous calcium hydroxide suspension (CHS) (Calxyl, OCO, Dirmstein, Germany).Methodology  Ten CHPP or CHP of size 50 were immersed into 5 mL isotonic sodium chloride solution. Conventional Ca(OH)2‐free gutta‐percha points served as negative control. Calcium release was measured up to 44 days by means of complexometric titration. Time dependent pH behaviour of all points in comparison with CHS was determined immersing 30 points of size 50 into 2.3 mL 0.9% wt NaCl‐solution at time intervals of 0.5–72 h by a microelectrode measuring chain and a pH‐meter. The surface morphologies of new and used gutta‐percha points were evaluated qualitatively under a scanning electron microscope. Statistical evaluation was carried out using Kolmogorov–Smirnov‐tests, Mann–Whitney‐tests and multifactorial anova.Results  For CHPP, a threefold greater calcium release was measured compared with CHP. Both types of points as well as CHS showed a maximum pH of approximately 12. Differences between groups were statistically significant for calcium release and pH (multifactorial anova; P < 0.001). Both types of points showed porous surfaces after usage, with a rougher surface for CHPP.Conclusions  CHPP and CHP increased the pH of isotonic sodium chloride >11 within 3 min. CHPP had a greater release of Ca2+ compared with CHP.
Presence of pores and vacuoles in set endodontic sealers
Authors: Mutal L. , Gani O. 
Published: September 2005

AbstractAim  To assess qualitatively the presence of pores and vacuoles in the structure of various endodontic sealers when set.Methodology  Eight specimens were prepared in keeping with Instituto Argentino de Racionalización de Materiales (IRAM) and ISO regulations for each of the 10 sealers assessed. Four specimens per sealer were examined to identify the presence of structural defects, termed pores, on the external surface. The remaining four specimens were used to examine the presence of defects on the surface exposed by cross‐sectional fracture; these were termed vacuoles. The largest and smallest diameters of the pores and vacuoles were measured by scanning electron microscope on both surfaces. The structural defects were classified according to their frequency as abundant, frequent, scarce or exceptional.Results  Pores and vacuoles were consistently found in every specimen of each sealer. However, their frequency and dimensions were greater in zinc‐eugenol‐based sealers than in epoxy‐resins and glass–ionomer sealers; they increased if the sealer contained calcium hydroxide. The diameter of the pores ranged from 5 to 320 μm and the diameter of the vacuoles ranged from 80 to 500 μm. The diameter of the vacuoles always exceeded that of the pores.Conclusions  Pores and vacuoles were a consistent finding in set sealers. Their frequency and size depended on the density of the sealer and increased when the sealers contained calcium hydroxide.
Temperature rise of the post and on the root surface during ultrasonic post removal
Authors: Budd J. C. , Gekelman D. , White J. M. 
Published: September 2005

AbstractAim  To determine the temperature rise on the root surface caused by ultrasonic post removal using different devices and techniques in a laboratory setting.Methodology  Two ultrasonic devices, one piezoelectrical (Pi) and one magnetostrictive (Ma), were investigated. A serrated titanium post was placed into the distal root canal of a human mandibular first molar. Four coolant parameters were utilized: no air, no water, no evacuation (NN), air only with high‐speed evacuation (A), 15 mL min−1 water coolant with high‐speed evacuation (W15) and 30 mL min−1 water coolant with high‐speed evacuation (W30). Five simulated post removals were measured at two locations, the post (P) and the root (R), for each coolant parameter. Temperature rise was measured at 30, 60, 90 and 120 s intervals using calibrated infrared thermography (n = 80). Temperatures were recorded at 45 ms intervals. Data were analysed using repeated measures anova with the Scheffe post hoc test (P ≤ 0.05).Results  The overall mean pooled effect showed that temperature rise for P = 20.1 ± 27.9 °C and R = 10.9 ± 7.9 °C were significantly different. Significant differences in temperature rise were: Pi > Ma, P > R, NN > A = W15 = W30 however, A > W30.Conclusions  There were significant differences in temperature rise as a function of ultrasonic device, location on the tooth and cooling method utilized for post removal.
Calcitonin gene‐related peptide receptor expression in healthy and inflamed human pulp tissue
Authors: Caviedes‐Bucheli J. , Arenas N. , Guiza O. , Moncada N. A. , Moreno G. C. , Diaz E. , Munoz H. R. 
Published: September 2005

AbstractAim  To use radioreceptor analysis for comparing calcitonin gene‐related peptide (CGRP) receptor expression in human pulp tissue samples collected from teeth having a clinical diagnosis of acute irreversible pulpitis, healthy pulps and teeth with induced inflammation.Methodology  Six pulp samples were obtained from teeth having a clinical diagnosis of acute irreversible pulpitis. Another eight pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic purposes. In four of these premolars, inflammation was induced prior to pulp collection. All the samples were processed and labelled with 125I‐CGRP. Binding sites were identified by 125I‐CGRP and standard CGRP competition assays.Results  CGRP receptor expression was found in all human pulp tissue samples. Most receptors were found in the group of pulps from teeth having a clinical diagnosis of acute irreversible pulpitis, followed by the group of pulps having induced inflammation. The least number of receptors was expressed in the group of healthy pulps. The Kruskal–Wallis and Mann–Whitney (post‐hoc) tests showed statistically significant differences between the groups (P < 0.05).Conclusion  CGRP receptor expression in human pulp tissue is significantly increased during inflammatory phenomena such as acute irreversible pulpitis.
Technical quality of root canal treatment and detection of iatrogenic errors in an undergraduate dental clinic
Authors: Eleftheriadis G. I. , Lambrianidis T. P. 
Published: September 2005

AbstractAim  To evaluate the technical quality of root canal treatment (RCT) and detect iatrogenic errors in an undergraduate dental clinic.Methodology  Three‐hundred and eighty‐eight root‐filled teeth from the records of the Department of Endodontology at the Aristotle University of Thessaloniki, Greece were evaluated. Evaluation of root‐filled teeth was based on two variables: length and presence of voids within the root filling. The technical standard of root fillings was categorized as: ≤2 mm from the apex with no voids (acceptable); >2 mm from the apex with no voids; overfilling with no voids; ≤2 mm from the apex with voids; >2 mm from the apex with voids and overfilling with voids. Iatrogenic errors that were detected included ledges, root perforations, furcation perforations, strip perforations and presence of fractured instruments. Chi‐squared analysis was used to determine statistically significant differences between frequencies of root fillings between each tooth type. Significant differences were also determined between frequencies of ledges and root perforations according to tooth type and separately in molars according to tooth number, canal location and root canal curvature.Results  Three‐hundred and forty‐three out of 620 root canals (55.3%) had a root filling that was classified as ‘acceptable’. The frequency of root canals with an ‘acceptable’ filling was significantly greater in the anterior teeth (72.1%) than in pre‐molars (55.2%) (P < 005) or in molars (46.7%) (P < 0.001). One‐hundred and fifty‐four (24.8%) root canals had ledges and 17 (2.7%) had a root perforation. The frequency of ledged root canals was significantly greater (P < 0.001) in molars than in anterior teeth. In molars, 105 out of 270 root canals (38.9%) had been ledged. Mesiobuccal, mesiolingual and distobuccal root canals were the most frequently ledged. Canal curvature was found to be the most important factor associated with ledges and root perforations.Conclusions  Technical quality was found to be acceptable more often in anterior teeth. Ledges were identified more often in curved canals in molar teeth.
The efficacy of ultrasonic irrigation to remove artificially placed dentine debris from human root canals prepared using instruments of varying taper
Authors: Van Der Sluis L. W. M. , Wu M‐K. , Wesselink P. R. 
Published: September 2005

AbstractAim  To investigate the influence of the taper of root canals on the effectiveness of ultrasonic irrigation to remove artificially placed dentine debris.Method  Forty‐four maxillary and mandibular canines were selected after bucco‐lingual and mesio‐distal radiographs indicated that their internal diameters were smaller than the diameters of a size 20, .06 taper System GT instrument (Dentsply Maillefer, Ballaigues, Switzerland). These canines were divided into three groups and prepared using either size 20, .06 taper System GT instruments, size 20, .08 taper or size 20, .10 taper System GT instruments. Each root was then split longitudinally through the canal, forming two halves. In one canal wall, a standard groove was cut 2–6 mm from the apex, to simulate uninstrumented canal extensions. Each groove was filled with dentine debris mixed with 2% NaOCl to simulate a situation when dentine debris accumulates in the uninstrumented canal extensions. Each canal was reassembled by joining the two halves of the teeth by means of wires and sticky wax. In each canal ultrasonic irrigation was performed with a size 15 K file using 2% NaOCl as an irrigant. Before and after irrigation, images of each half of the canal with a groove were taken using a microscope and a digital camera, after which they were scanned into a PC as TIFF images. The quantity of dentine debris in the groove was evaluated using a scoring system: the higher the score, the larger the amount of debris. The scores before and after irrigation were compared. The differences in percentage of score reduction between the three groups were analysed by means of one‐way anova.Results  After ultrasonic irrigation, the debris score reduced by 74, 81 and 93%, respectively, in the size 20, .06, 20, .08 and 20, .10 taper groups. However, the difference amongst groups was not statistically significant (P = 0.078).Conclusion  There was a tendency that ultrasonic irrigation was more effective in removing artificially placed dentine debris from simulated canal extensions from canals with greater tapers.
Quality of care: the need for medical, contextual and policy evidence in primary care
Authors: Van Driel Mieke L. , De Sutter An I. , Christiaens Thierry C. M. , De Maeseneer Jan M. 
Published: September 2005

AbstractThe increasing availability of medical evidence in clinical practice was expected to improve the quality of care. However, this has not been realized. A possible explanation is that quality of care is a complex concept and needs a wider scope. Starting from the Donabedian triangle of structure, process and outcome, a framework for the analysis of quality of care is presented. The need for three types of evidence is identified and discussed: medical, contextual and policy evidence. Although the body of medical evidence is increasing, it has major flaws and gaps hampering its applicability in primary care. There is also a need to focus on the context of the medical encounter, which has been shown to influence outcome, but is still not well researched. Finally, evidence on costs, cost utility and equity needs to be considered. Taking these different aspects of evidence into account, an agenda for research in primary care is set. The analytical framework may provide new insights in the quest for improving quality of health care.