bluuebunny/crossref_metadata_2025 huggingface dataset:
Case of unilateral focal dermal hypoplasia (Goltz syndrome)
Authors: AOYAMA Masako , SAWADA Hiroo , SHINTANI Yoichi , ISOMURA Iwao , MORITA Akimichi
Published: September 2010

Focal dermal hypoplasia (FDH) is a rare multisystem condition in which developmental defects of the skin are associated with ocular, dental and skeletal abnormalities. Herein, we report an 8‐year‐old girl with FDH. Her body halves were asymmetric and she had linear cutaneous atrophy with yellow nodules on her extremities. Syndactylies of the third and fourth fingers of the right hand and second and third toes of the right foot were also observed. Histological examination revealed dermal hypoplasia and upward extension of the adipose tissue. Based on these observations, she was diagnosed with unilateral FDH.
Effects of narrow‐band ultraviolet B and tazarotene therapy on keratinocyte proliferation and TIG3 expression
Authors: LUO Suju , ZHENG Yan , PENG Zhenhui , JIANG Ju , GONDOKARYONO Srie , WANG Guorong , IKEDA Shigaku
Published: September 2010

Tazarotene plus narrow‐band ultraviolet B (NB‐UVB) therapy has been shown to enhance the efficacy in treating patients with psoriasis, while the mechanism is not clear. The present study aims to investigate the alteration of cell proliferation and TIG3 in cultured normal human keratinocytes after NB‐UVB and/or tazarotene treatment. Keratinocytes were exposed to NB‐UVB, then incubated with or without tazarotene, and then cell proliferation was detected by methyl thiazoleterazolium colorimetric assay and TIG3 mRNA expression and protein production was examined by real‐time reverse transcription polymerase chain reaction and immunocytochemistry, respectively. The results show that keratinocyte proliferation was inhibited and TIG3 mRNA expression and protein production were elevated by tazarotene at a dose higher than 0.1 µmol/L. In NB‐UVB single irradiating groups, only 200 mJ/cm2 NB‐UVB inhibited keratinocyte proliferation, and none of the irradiated groups had an effect on TIG3 expression. Moreover, tazarotene plus NB‐UVB have stronger effects than those separately. These results indicate NB‐UVB plus tazarotene may have synergistic effects on inhibiting keratinocyte proliferation and elevating TIG3 expression, which may have some implications for the understanding of how to treat psoriasis patients with tazarotene plus NB‐UVB.
The Severity of Alcohol Dependence Questionnaire: Its Use, Reliability and Validity
Authors: Stockwell Tim , Murphy Denis , Hodgson Ray
Published: September 2010

The clinical value of assessing degree of alcohol dependence is discussed in relation to goals of treatment. Further information is then provided on the use, reliability and validity of an instrument designed for this purpose ‐the SADQ. ‘Norms’ for SADQ scores from three samples of problem drinkers are given. Data indicating that individual items, sections and also the total scores of the SADQ have consistently high test‐retest reliability coefficients are presented. A study is described in which a degree of construct validity is established by relating SADQ scores to one important component of the alcohol dependence syndrome [2]‐narrowing of drinking repertoire. In addition, it is shown that SADQ scores have low, but significant, correlations with indicators of withdrawal severity for individuals treated at a Detoxification Unit. SADQ scores failed to correlate with indices of liver functioning. These results are discussed and it is concluded the SADQ is a quick, reliable and valid instrument.
Long‐term drainage for forestry inhibits extracellular phenol oxidase activity in Finnish boreal mire peat
Authors: Toberman H. , Laiho R. , Evans C. D. , Artz R. R. E. , Fenner N. , Straková P. , Freeman C.
Published: September 2010

Drainage for forestry has been amongst the most extensive of land management practices applied to northern latitude peatlands, particularly in northern Europe. Extracellular phenol oxidases play an important role in the carbon cycle of soils. This study investigated the effects of long‐term (45 years) drainage for forestry upon surface peat extracellular phenol oxidase activity, soluble phenolic concentrations and pH at ombrotrophic bog, oligotrophic fen and mesotrophic fen sites at a Finnish mire complex. Phenol oxidase activity was reduced by drainage at all three sites. Phenol oxidase activity was positively correlated with peat pH across all sites irrespective of drainage treatment, suggesting that pH is a major factor influencing peat phenol oxidase activity at the mire complex. Peat pH became more acidic with drainage at the fen sites, and it is likely that this contributed to the suppression of peat phenol oxidase activity. The reduction of peat phenol oxidase activity with drainage was accompanied by increased concentrations of water‐soluble phenolics at all three sites, and the potential contribution of this to changes in peat carbon stocks following drainage is discussed.
Water repellency of fly ash‐enriched forest soils from eastern Germany
Authors: Hartmann P. , Fleige H. , Horn R.
Published: September 2010

Fly ash‐enriched soils occur widely throughout the industrial regions of eastern Germany and in other heavily industrialized areas. A limited amount of research has suggested that fly ash enrichment alters the water repellency (WR) characteristics of soil. This study concentrates on the influence of fly ash enrichment on WR of forest soils with a focus on forest floor horizons (FFHs). The soils were a Technosol developed from pure lignite fly ash, FFHs with lignite fly ash, and FFHs without lignite fly ash enrichment. Three different methods (water drop penetration time, WDPT, test; water and ethanol sorptivity measurement and the derived contact angle, θR; and the Wilhelmy‐plate method contact angle, θwpm) were used to characterize soil WR. Additionally, carbon composition was determined using 13C‐NMR spectra to interpret the influence of the organic matter.

This study showed that the actual WR characteristics of undisturbed, fly ash‐enriched soils can be explained in terms of the composition of soil organic matter, with the fly ash content playing only a minimal role. Regardless of the huge amounts of mainly mineral fly ash enrichment, all undisturbed FFHs were comparable in their WR characteristics and their carbon compositions, which were dominated by recently‐formed organic substances. The pure fly ash deposit was strongly influenced by lignite remains, with the topsoil having a greater content of recent plant residues. Thus, the undisturbed topsoil was more repellent than the subsoil. When homogenized samples were used, we found a distinct effect of fly ash enrichment and structure on WR. Water repellency of the pure fly ash horizons did not differ distinctly, while the fly ash enrichment in the FFHs caused a significant reduction in WR. The methods used (WDPT, θR and θwpm) identified these differences similarly. These results led to the assumption that water‐repellent structures of the topsoils were probably the result of hydrophobic coatings of recently formed organic substances, whereby the initially high wettability of the mainly mineral, hydrophilic fly ash particles was reduced.
Quantifying rhizosphere particle movement around mutant maize roots using time‐lapse imaging and particle image velocimetry
Authors: Vollsnes A. V. , Futsaether C. M. , Bengough A. G.
Published: September 2010

Soil surrounding a growing root must be displaced to accommodate the increased root volume. To ease soil penetration, root caps produce border cells and mucilage that lubricate the root surface, decreasing friction at the root‐soil interface. Rhizosphere deformations caused by roots with or without a functional root cap were compared to determine the effects of the root cap on sand displacement and penetration. Intact (KYS wild type) and decapped (agt1dec mutant) primary maize roots were grown in observation chambers filled with sand. Non‐destructive time‐lapse micro‐imaging combined with particle image velocimetry was used to visualize and quantify sand displacements as small as 0.5 µm caused by growing roots. Decapped (agt1dec) roots displayed typical responses of mechanically impeded roots at sand densities that did not affect intact KYS roots. Sand displacement decreased exponentially with distance from the root and extended four to eight root radii into the sand. The calculated mean sand density increase and the compressed sand area were doubled by decapping. Maximum density often occurred in front of the apex of decapped roots whereas it occurred along the sides of intact roots. Periodic variation in sand deformation was observed, probably associated with root circumnutation, which may also facilitate soil penetration. Sand particles moved alongside KYS roots more easily than they did alongside agt1dec roots. A functional exuding cap was therefore essential for efficient rhizosphere deformation and penetration by roots. Manipulating root tip, and specifically root cap, properties is a possible target for improving root penetration in hard soil.
A controlled neuropsychological study of HIV‐seropositive and HIV‐seronegative adolescent haemophiliacs
Authors: THOMPSON C. , WESTWELL P. , VINEY D. , WILSON B. A. , HILL F. , HARRINGTON R. , BRYANT T. N. , PICKERING R.
Published: September 2010

Sixty‐four males with haemophilia were assessed with a series of neuropsychological tests and a structured interview for psychiatric symptoms. Thirty‐one had been infected with human immunodeficiency virus (HIV) before the age of 18 and were in various stages of the disease at the time of testing and 33 were HIV negative. Sixteen male control subjects were recruited to match in age with the haemophilia group. The HIV‐seropositive group were older than the HIV‐negative group due to the cohort effect of the time of infection. Contrary to predictions from the known effects of HIV on the central nervous system the HIV‐seropositive group performed better on many of the tests than the HIV‐seronegative group. In some but not all of the tests this may have been an age effect. There was very little psychiatric morbidity, consistent with the view that high levels of psychological support provided by the haemophilia units can alleviate the effects of the illness on emotions and behaviour. These findings form a baseline for a 2‐year follow‐up study which is in progress.
Potency measurement of factor VIII in recombinant concentrates
Authors: FARRUGIA A. , ROCHFORT P. , FRY K. J. , TRAN E. , POULIS M.
Published: September 2010

In preliminary studies on the stability of recombinant factor VIII (rFVIII) concentrates post reconstitution, a rise in potency to 200% of labelled values was observed in concentrates stored at 22 °C over 24 h. This was observed in potency estimates by the one‐stage clotting, but not the two‐stage clotting or chromogenic assays, and was not observed for intermediate‐purity product derived from plasma (IPVIII). Use of human serum albumin (HSA), rather than the usual bovine material (BSA), to dilute product for the stability study abolished the rise in potency. Incorporating purified von Willebrand Factor (VWF) in the diluent buffer abolished the rise observed in BSA. A similar rise was observed upon incubating rFVIII in the presence of 10−4 u of thrombin per mL in HSA buffer. Potency estimates using the HSA in the dilution buffer resulted in severe underpotency in relation to the label claim when using the two‐stage clotting and the chromogenic assays, but not the one‐stage clotting assay. Predilution in severe haemophilic plasma restored potency levels to those claimed. We conclude that (i) commercial preparations of BSA may be unsuitable for inclusion in buffers for rFVIII studies; (ii) FVIII in rFVIII concentrates is exquisitely sensitive to activation by thrombin, presumably as a result of the lack of VWF; (iii) accurate potency estimation in the two‐stage assay systems requires VWF in the assay system.
Comparison of the quality of life between HIV‐positive haemophilia patients and HIV‐negative haemophilia patients
Authors: DJULBEGOVIC B. , GOLDSMITH G. , VAUGHN D. , BIRKIMER J. , MARASA M. , JOSEPH G. , HUANG A. , HADLEY T.
Published: September 2010

Summary. In a prospective study, we tested the hypothesis that an already reduced quality of life in haemophilia patients is further diminished in those haemophilia patients who contracted the human immunodeficiency virus (HIV) as a result of transfusion of coagulation factor preparations. From an available pool of 92 males with haemophilia A or B, 18 patients seropositive for HIV infection and 11 seronegative patients were randomly selected for the study.

We applied two instruments to measure the quality of life (QOL) in our patients. The first instrument was the quality of well‐being (QWB) scale that unifies QOL into a single score based upon an assessment of the patient's symptoms and health‐related reductions in mobility, physical activity and social activity. The second instrument was SF‐36, the questionnaire from the Medical Outcome Study (MOS) that measures six dimensions of health status (physical functioning, role functioning, social functioning, pain, mental health and health perception). Measurements were obtained with both instruments at three interviews with each patient over a 1‐year interval.

As expected, HIV disease reduces QOL in haemophiliacs. The number of bleeding episodes within 2 months of interview was increased in the HIV‐positive cohort but not within 6 days of interview, indicating that HIV disease independently affects QOL in haemophilia patients. In a typical 30‐year‐old patient, haemophilia itself has reduced quality of their lives by 9.3 years, and HIV disease additionally from 8.5 to 20 years. On the MOS scales, the two patient groups differed significantly only in the dimensions of health perception and pain magnitude. Although HIV disease led to a decrement in QOL of haemophilia patients, it also appears that haemophilia patients are able to develop coping skills to prevent more drastic effects of HIV disease on their QOL. Future studies will need to explore the nature and mechanisms of this ‘buffering’ effect.
Clinical endodontic and surgical management of tooth and associated bone resorption
Authors: HEITHERSAY GEOFFREY S.
Published: September 2010

Summary. The management of root and bone resorption has been divided on clinical grounds into four categories:

(i)conditions that respond to conservative endodontics;

(ii) conditions that require surgical endodontics;

(iii) conditions that require combined therapy, e.g. endodontics, orthodontics, periodontics, prosthodontics;

(iv) conditions that will not respond to, or do not require any, treatment.

Using this classification, a conservative treatment rationale based on an understanding of the underlying disease can be evolved.

The diagnosis of whether the lesion is internal, external or combined is essential if rational therapy is to be carried out. Internal resorption requires the removal of the blood supply supporting this resorptive defect; the process should cease, provided that this can be effectively achieved.

External root resorption is more complicated, requiring either stimulation of natural repair processes by removing the aetiological agents, artificial repair involving the curettage of the defect and the placement of a suitable repair material, or partial or complete resection. Combined therapy involving orthodontic extrusion is useful in some defects at or near the cervical region.

Treatment should not be instituted where there is no therapeutic advantage or where the process would naturally cease with the removal of the initiating cause.
The influence of different engine‐driven, sound ultrasound systems and the Canal Master on root canal preparation: an in vitro study
Authors: MARROQUÍN B. BRISEÑO , SOBARZ0‐NAVARRO V. , DEVENS S.
Published: September 2010

Different methods and automated devices have been developed to accomplish the enlarging and debriding of root canals. The occurrence of undesired effects on the root canal walls was compared in vitro between a theoretically ideally shaped canal and the Canal Leader, Canal Finder, 3000 Endo Sonic Air, Cavi Endo 25, Enac System, Piezon Master 400 and the Canal Master. Clear casting resin models were used for this purpose. A photographic double exposure was used to superimpose the images of the original canals on the enlarged canals, thus enabling measurement of the material removed. Measurements were made at six different points. Significance was defined at the 5% level (P= 0.05).

Ail instruments and/or devices, with the exception of the Cavi Endo 25. enlarged the convex side of the canals significantly greater at level 1 in comparison to the ideal. On the concave side, significantly smaller differences were found between the ideal and the results of all the enlarging devices, with the exception of the Canal Master. On the convex side at level 2, the Canal Leader, Canal Finder, Cavi Endo, Enac System and Endo Sonic Air showed no statistical differences between ideal and effective material removal. The Piezon Master showed significantly lower material removal in comparison to the ideal. The Canal Master demonstrated statistically higher differences when compared with the ideal. On the concave side, all devices showed a statistically higher difference between the ideal and actual material removed, with the exception of the Canal Master and Cavi Endo. On the convex side at level 3, the Canal Finder, Canal Leader, Endo Sonic Air and Cavi Endo removed significantly less material than desired. At this level on the concave side, the Canal Master removed insignificantly more material than ideal. All other devices exhibited statistically higher differences.
Simulation models for teaching endodonticsurgical procedures
Authors: JACKSON A.P. , TIDMARSH B.G.
Published: September 2010

Models which simulate oral conditions pertaining to endodontic surgical procedures are most suitable if they contain natural teeth and have hard and soft tissues which handle realistically. In addition, the model should possess radiological characteristics similar to bone. A simple custom‐b&t model which fulfils these requirements is described.
Efficacy of various concentrations of NaOCl and instrumentation techniques in reducing Enterococcus faecalis within root canals and dentinal tubules
Authors: Berber V. B. , Gomes B. P. F. A. , Sena N. T. , Vianna M. E. , Ferraz C. C. R. , Zaia A. A. , Souza‐Filho F. J.
Published: September 2010

Aim  To evaluate the efficacy of 0.5%, 2.5% and 5.25% sodium hypochlorite (NaOCl) as intracanal irrigants associated with hand and rotary instrumentation techniques against Enterococcus faecalis within root canals and dentinal tubules.

Methodology  A total of 180 extracted human premolar teeth were infected for 21 days with E. faecalis. The specimens were divided into 12 groups, as follows: group 1: 5.25% NaOCl + Hybrid technique (Valdrighi et al. 1998); group 2: 5.25% NaOCl + nickel–titanium (NiTi) rotary technique 4 mm shorter than the apex (by FOP‐UNICAMP); group 3: 5, 25% NaOCl + NiTi rotary technique (Hero 642); group 4: 2.5% NaOCl +Hybrid technique; group 5: 2.5% NaOCl + NiTi rotary technique 4 mm shorter than the apex; group 6: 2.5% NaOCl + NiTi rotary technique (Hero 642); group 7: 0.5% NaOCl + Hybrid technique; group 8: 0.5% NaOCl + NiTi rotary technique 4 mm shorter than the apex; group 9: 0.5% NaOCl + NiTi rotary technique (Hero 642); group 10: sterile saline solution + Hybrid technique; group 11: sterile saline solution + NiTi rotary technique 4 mm shorter than the apex; group 12: sterile saline solution + NiTi rotary technique (Hero 642). Canals were sampled before and after preparation. After serial dilution, samples were plated onto brain heart infusion (BHI) agar, and the colony forming units (CFU) that were grown were counted. The teeth were sectioned into three thirds and dentine chips were removed from the canals with conical burs. The samples obtained with each bur were immediately collected into test tubes containing BHI broth, and were incubated at 37 °C and plated onto BHI agar. The CFU were counted and analysed.

Results  At all depths and thirds of the root canals and for all techniques used, 5.25% NaOCl was shown to be the most effective irrigant solution tested when dentinal tubules were analysed, followed by 2.5% NaOCl. No differences among concentrations in cleaning the canals were found.

Conclusions  Especially at higher concentrations, NaOCl, was able to disinfect the dentinal tubules, independent of the canal preparation technique used.
The adhesion between fibre posts and composite resin cores: the evaluation of microtensile bond strength following various surface chemical treatments to posts
Authors: Vano M. , Goracci C. , Monticelli F. , Tognini F. , Gabriele M. , Tay F. R. , Ferrari M.
Published: September 2010

Aim  To evaluate the influence of various surface treatments to fibre posts on the microtensile bond strength with different composite resins.

Methodology  A total of 110 fibre posts were randomly divided into five groups, according to the surface pre‐treatment performed. Group 1: immersion in 24% H2O2 for 10 min and silanization for 60 s; group 2: immersion in 10% H2O2 for 20 min and silanization for 60 s; group 3: immersion in 4% hydrofluoric acid gel for 60 s and silanization for 60 s; group 4: silanization of the post surface for 60 s and application of the bonding agent G‐Bond; group 5: silanization of the post surface for 60 s (control group). After treatment, two posts were randomly selected from each group to evaluate the morphological aspect of the post surface with scanning electron microscopy. The remaining posts in each group were divided into five subgroups of five posts each, which differed in the type of composite resin used for the core build‐up. Post‐core strength were calculated and the differences among experimental groups were analysed with two‐way anova and the Tukey test (α = 0.05).

Results  The post‐core strengths achieved in groups 1 and 2 were significantly higher (P < 0.05), than those of groups 3, 4 and 5. The post‐core strength in the control group was significantly lower (P < 0.05) than all other groups.

Conclusions  Hydrogen peroxide and hydrofluoric acid both modified the surface morphology of fibre posts and with silane, significantly enhanced the interfacial strength between them and core materials.
Ex vivo study of the efficacy of H‐files and rotary Ni–Ti instruments to remove gutta‐percha and four types of sealer
Authors: Kosti E. , Lambrianidis T. , Economides N. , Neofitou C.
Published: September 2010

Aim  To compare the efficacy of ProFile rotary Nickel–Titanium (Ni–Ti) instruments and Hedstroem‐files (H‐files) combined with Gates‐Glidden (GG) drills during removal of gutta‐percha root fillings used in combination with one of the four representative sealers.

Methodology  Forty‐eight single‐rooted human teeth, with fully formed apices and straight root canals were used. The root canals were accessed and instrumented using a stepback technique with H‐files. They were randomly assigned to four groups and subsequently filled with a combination of lateral and vertical condensation of gutta‐percha and one of the following sealers: Roth 811, AH26, Endion and Roekoseal. The root fillings were removed 1 year later, using either H‐files in combination with GG drills or the ProFile Ni–Ti system. Teeth were then grooved longitudinally and split. The amount of gutta‐percha and sealer remaining on the root canal walls was traced and scored visually with the aid of a stereomicroscope. The scores were analysed and statistically compared with the Kruskal–Wallis test between the ProFile and H‐file groups, as well as among the four sealer subgroups. Two samples from each group were studied under the scanning electron microscope to enhance inspection of canal walls and remaining material.

Results  Sealer remnants were observed with both techniques mainly in the middle and apical third of the root canal. The ProFile system and the H‐files were associated with similar amounts of remaining filling material (P > 0.05). In the cervical third of the root canal all sealer remnants were removed with both techniques. In the middle and apical third AH26 was associated with a statistically significant greater quantity of remnants on the root canal walls with both removal techniques (P < 0.05). Endion, Roth 811 and Roekoseal were associated with approximately the same amount of filling material in the middle third of the root canal (P > 0.05), whereas in the apical third Endion was associated with significantly more remnants of filling material than the other two sealers with either ProFile or H‐files (P < 0.05).

Conclusions  None of the methods used for the removal of root fillings was totally effective, especially in the apical third of the root canal.
Removal efficacy of various calcium hydroxide/chlorhexidine medicaments from the root canal
Authors: Lambrianidis T. , Kosti E. , Boutsioukis C. , Mazinis M.
Published: September 2010

Aim  To compare the efficiency of removing calcium hydroxide [Ca(OH)2]/chlorhexidine (CHX) (gel), Ca(OH)2/CHX (solution) and Ca(OH)2/saline pastes with the use of instrumentation and irrigation with sodium hypochlorite and ethylene diamine tetraacetic acid (EDTA) solutions. Moreover the role of the patency file in the cleanliness of the apical third of the root canal was evaluated.

Methodology  Sixty‐four human single‐rooted teeth with straight canals were used. Root canal preparation was performed with a stepback technique using Hedström (H) files. Teeth were randomly assigned to three groups and subsequently filled with one of the pastes: Ca(OH)2/CHX (gel), Ca(OH)2/CHX (solution) and Ca(OH)2/saline paste. The medicaments were removed 10 days later using instrumentation and irrigation with 1% sodium hypochlorite and 17% EDTA, with or without obtaining patency of the apical foramen with a size 10 H‐file. The crowns were removed at the cemento‐enamel junction and the roots were grooved longitudinally and split into halves. Images of all halves were acquired with the use of a flatbed scanner. A scoring system of 1 to 4 was used to assess the amount of residue on the cervical, middle and apical third of the canal. Data were subjected to statistical analysis using Kruskal–Wallis and Mann–Whitney tests, with Bonferroni correction, at 95% confidence level (P < 0.05).

Results  Remnants of medicament were found in all experimental teeth regardless of the experimental material used and the use of the patency file. When examining the root canal as a whole, Ca(OH)2/CHX (gel) paste was associated with significantly larger amount of residue, whereas the Ca(OH)2/CHX (solution) paste was associated with less amount (P < 0.05) than the other two medicaments with or without the use of a patency file.

Conclusions  None of the techniques used in this study removed the inter‐appointment root canal medicaments effectively; the use of the patency file facilitated removal of more of the medicament in the apical third of those straight canals.
A comparative study of root canal preparation with NiTi‐TEE and K3 rotary Ni‐Ti instruments
Authors: Jodway B. , Hülsmann M.
Published: September 2010

Aim  To evaluate and compare several parameters of curved root canal preparation using two different Ni‐Ti systems: NiTi‐TEE (Sjöding Sendoline, Kista, Sweden) and K3 (Sybron Endo, Orange County, CA, USA).

Methodology  Fifty extracted mandibular molars with mesial root canal curvatures ranging from 20 to 40° were divided into two groups. In one group, 50 root canals were instrumented using NiTi‐TEE files to an apical size 30; 0.04 taper (the largest available size at the time of this study). In the other group, 50 root canals were prepared with K3 instruments to an apical size 45; 02 taper. Both systems were used in a crowndown manner, with copious NaOCl (3%) irrigation and a chelating agent (Calcinase Slide, lege artis, Dettenhausen, Germany), employing torque‐controlled motors. For assessment of shaping ability, pre‐ and postinstrumentation radiographs and cross‐sectional photographs of canals were taken and changes in canal curvature and root canal diameter documented. Cleaning ability was evaluated by investigating specimens of the apical, medial and coronal third of the root canal wall under a scanning electron microscope using 5‐score indices for debris and smear layer. Procedural errors (instrument separations, perforations, apical blockages, loss of working length) and working time were recorded. Nonparametric anova was used to compare straightening of canal curvatures, canal cross‐sections and canal wall cleanliness (P < 0.05), whereas working time was analysed using the parametric anova (P < 0.05).

Results  Both Ni‐Ti systems maintained curvature well: the mean degree of straightening was 0.2° for NiTi‐TEE and 0.4° for K3 with no statistical significance between the groups. Post‐instrumentation cross‐sections of the root canals revealed an acceptable contour (round or oval) in 50.6% of cases for the NiTi‐TEE group and in 65.3% of cases for the K3 group. The difference was not significant. The SEM investigation of canal walls showed equally good debris removal for both systems: NiTi‐TEE prepared canal walls in 74.7% of cases with scores I and II; K3 achieved these scores in 78.7% of cases. For smear layer, NiTi‐TEE and K3 only received good scores (I and II) in 38.7% and 40% of canal wall specimens, respectively. For both parameters, no significant differences were found between groups. File fractures did not occur, but loss of working length was observed in one case following the preparation with NiTi‐TEE and in three cases during K3 instrumentation. Mean working time was significantly shorter for NiTi‐TEE (170 s) than for K3 (208 s).

Conclusions  Both systems maintained original canal curvature well and were safe to use. Whilst debridement of canals was considered satisfactory, both systems failed to remove smear layer sufficiently.
The trade‐off between thermal tolerance and behavioural dominance in a subtropical South American ant community
Authors: Bestelmeyer Brandon T.
Published: September 2010

1. The distribution, ecology, and behaviour of ants (Hymenoptera: Formicidae) is profoundly influenced by environmental stress and competition. As in plants, trade‐offs in adaptations to these factors are the basis for functional classifications of ant taxa and communities at a global scale.

2. Theory predicts a trade‐off between stress tolerance and competitive dominance in both plants and ants. In ants, low temperature is thought to be stressful, so I hypothesized that there would be a positive relationship between temperature and behavioural dominance. I evaluated this relationship in a South American, Chaco ant community.

3 The activity and behaviour of ground‐foraging, omnivorous ants were examined at baits in open and closed, forested habitats during different seasons and times of day to characterize the responses of ant taxa to variation in microclimate and competitors.

4. Behaviourally dominant ants were most active at moderately high temperatures, whereas subordinate species were active at extreme temperatures, when they had virtually exclusive access to resources.

5. The patterns presented here and those observed in other studies suggest that there is a general trade‐off between behavioural dominance and thermal tolerance in ants. This trade‐off creates a linear relationship between temperature use and dominance for ants up to ≈ 35 °C, but extremely high temperatures may also be stressful such that the full relationship is actually unimodal.
Breeding territory size affects fitness: an experimental study on competition at the individual level
Authors: Both Christiaan , Visser Marcel E.
Published: September 2010

1.Descriptive studies have shown that the annual mean fecundity and survival in bird populations decline as density increases. Experimental studies in which breeding density has been manipulated show that density causally affects reproduction in some but not other species.

2.In a 3‐year study on great titsParus majorwe manipulated density by removing about one‐third of territorial great tit pairs from half the study area each year. The removal resulted in an increase in territory size of the remaining birds in the experimental sub‐area.

3.Fecundity and survival did not differ between the experimental low‐density and the control sub‐areas. The experiment thus did not show a causal relationship between breeding density and fecundity and survival at the level of the population.

4.The data were analysed further with respect to individual territory size, the level at which competition is assumed to operate. Pairs in the experimental sub‐area enlarged their territories. We argue that variation in territory enlargement is not caused by individual quality.

5.Both pre‐manipulation territory size and territory enlargement positively affected the probability that a territorial pair nested, the growth rate of their chicks, the number of fledglings that recruited into the breeding population and the survival of the territorial adults. No effect of territory enlargement was observed on clutch size, nor on the probability that pairs started a second brood.

6.The positive effect of the experimental territory enlargement argues for a causal effect of territory size on these reproductive parameters, independent of individual quality.

7.An effect of the density reduction on fecundity may not be detectable at the population level, either due to the large variation in territory sizes within the experimental treatments or to the negative effect of the experimentper se, which counter balances the positive effect of territory enlargement.
Species‐specific utilization of food sources by sympatric woodlice (Isopoda: Oniscidea)
Authors: Zimmer Martin , Topp Werner
Published: September 2010

1. In long‐term laboratory studies, the influence of different food materials on parameters of population dynamics was compared in the sympatric woodlice, Porcellio scaber and Oniscus asellus, as a measure of interspecific differences in the utilization of food.

2. Freshly fallen leaf litter of different tree species had been acidified and microbially inoculated prior to the experiments. By analysing the influence of pH level, density and activity of litter‐colonizing microbiota and several physico‐chemical characteristics of the leaf litter, we obtained information on those factors that determine food quality.

3. The studied species responded similarly to different leaf litter species in that both P. scaber and O. asellus performed better on litter with low C:N ratio. Overall, both isopod species reproduced more successfully on litter with higher pH levels, containing half the levels of tannins and other phenolics.

4. Interspecific differences were obvious with respect to the significance of litter‐colonizing microbiota, and the dependence of juveniles on particular food parameters. While the performance of adult P. scaber was influenced by both litter‐colonizing microbiota and physico‐chemical characteristics of the leaf litter, adult O. asellus were influenced by leaf litter characteristics, but not by litter‐colonizing microbiota. Juvenile mortality was affected by the tested food parameters in O. asellus, but not in P. scaber. Growth rates of juveniles of both species were influenced by physico‐chemical characteristics of the leaf litter. Additionally, leaf litter microbiota had a significant influence on growth rates in juvenile P. scaber, but not in juvenile O. asellus.

5 Reasons for, and consequences of, similarities and differences between the observed sympatric species, and intraspecific differences between ontogenetic stages, are important aspects of soil ecology and may help explain the sympatric coexistence of two species belonging to the same guild of saprophagous soil animals.
Population density of migratory and resident brown trout (Salmo trutta) in relation to altitude: evidence for a migration cost
Authors: Bohlin T. , Pettersson J. , Degerman E.
Published: September 2010

For anadromous salmonids, the positive relations found in previous studies between adult size/age and stream characteristics suggest that the migration cost increases with stream length, water discharge and the altitude of the spawning site. In this study we hypothesized that the altitude of the spawning site is positively related to the migration effort.

Life‐history theory predicts (i) that the equlibrium egg density, which is a fitness measure, thereby will decline more rapidly with altitude in migratory than in stream‐resident populations, and therefore (ii) that residency will be selected for at large enough altitudes.

As the density of juveniles is a function of egg density, we hypothesized that (a) altitude has stronger effect on juvenile density in migratory than in resident populations, and (b) juvenile density is larger in migratory than in resident populations.

We tested (a) and (b) using multivariate methods for electrofishing data from 164 sea‐migratory and 167 stream‐resident populations of brown troutSalmotruttaL. in Sweden. Both predictions were supported; the juvenile density was larger and declined more rapidly with altitude in migratory than in resident populations.

The results are further evidence that migration costs reduce fitness in anadromous salmonids.
Long‐term variability in secondary production of an intertidal bivalve population is primarily a matter of recruitment variability
Authors: Van Der Meer Jaap , Beukema Jan J. , Dekker Rob
Published: September 2010

The importance of recruitment processes in determining benthic population dynamics has received considerable interest among marine ecologists in the last two decades. Observational demographic studies, in which recruits were followed to and through the adult state, aimed to estimate whether the variation in the numbers of recruits is dampened by density‐dependent post‐recruitment processes. These studies revealed conflicting results on the importance of post‐recruitment density dependence, but were performed over at most a few years.

Based on a study of the demography and growth of the bivalve Macoma balthica (L.) on an intertidal flat in the Dutch Wadden Sea for a period of almost 30 years, we explored the extent to which the among‐cohort variability in recruitment was reflected in the secondary production (which results from the combined action of recruitment, mortality and growth) of the adult population.

Since growth in length was of the Von Bertalanffy type and post‐recruitment instantaneous mortality rate was approximately constant for each cohort, production could be explicitly written in terms of the following parameters: recruit density, condition (ratio of mass to cubic length), Von Bertalanffy growth coefficient, asymptotic cubic length, and expected life span.

Decomposing the among‐cohort variability in production in terms of the covariance matrix of these parameters revealed that most of the variance in production could be attributed to year‐to‐year variability in recruit density.

Small negative covariances between recruit density and asymptotic size and expected life span indicated weak density dependence after recruitment.

The major cause of temporal variation in abundance and production is inter‐annual variation in recruitment and competition for resources seems to play a small role in affecting post‐recruitment population density and production.
Predator behaviour and prey density: evaluating density‐dependent intraspecific interactions on predator functional responses
Authors: P. Anders Nilsson
Published: September 2010

In models of size‐structured predator–prey systems, the effects are evaluated of gape‐size limited predation on prey population growth and density when predators are non‐interacting, cannibalistic, interfering, and cannibalistic and interfering.

Predation from non‐interacting predators markedly reduces prey density, compared with prey densities in the absence of predation. When density‐dependent cannibalism between predators is introduced, predator density and therefore total functional response decrease, resulting in a decrease in predation pressure and higher prey densities.

Size‐ and density‐dependent interference between predators substantially decreases functional responses in the predators, and the prey population is thus allowed to grow more dense. Allowing for cannibalism between interfering predators also decreases predator density, but here the decreased number of predators does not have the releasing effect seen in solely cannibalistic predators. The interference between predators decreases with predator density, and per capita functional responses increase and compensate for the decrease in predator density.

These theoretical results are compared with results from natural systems with pikeperch and northern pike. Both species are cannibalistic, and pike are also kleptoparasitic, mirroring the models. Results from introductions of the different piscivores into natural systems corroborate the outcome of the models, since introduction or increased densities of pikeperch have shown to have severe and long‐lasting effects on prey, while pike have only initial, decreasing over time effects on prey stock. Thus, predator behaviour may seriously affect predator impact on prey, and size‐ and density‐dependent interactions between predators may be a major key to the understanding of predator–prey dynamics and community composition in lakes.
Non‐competitive phenotypic differences can have a strong effect on ideal free distributions
Authors: Ruxton Graeme D. , Humphries Stuart , Farnsworth Keith D.
Published: September 2010

We present a model of the ideal free distribution (IFD) where differences between phenotypes other than those involved in direct competition for resources are considered. We show that these post‐acquisitional differences can have a dramatic impact on the predicted distributions of individuals.

Specifically, we predict that, when the relative abilities of phenotypes are independent of location, there will be a continuum of mixed evolutionarily stable strategy (ESS) distributions (where all phenotypes are present in all patches).

When the relative strengths of the post‐acquisitional trait in the two phenotypes differ between patches, however, we predict only a single ESS at equilibrium. Further, this distribution may be fully or partially segregated (with the distribution of at least one phenotype being spatially restricted) but it will never be mixed.

Our results for post‐acquisitional traits mirror those ofParker (1982)for direct competitive traits. This comparison illustrates that it does not matter whether individual differences are expressed before or after competition for resources, they will still exert considerable influence on the distribution of the individuals concerned.
A hidden cost of reproduction: the trade‐off between clutch size and escape take‐off speed in female zebra finches
Authors: Veasey Jake S. , Houston David C. , Metcalfe Neil B.
Published: September 2010

The concept of reproductive costs is a central tenet of life‐history theory, but the proximate mechanisms whereby such costs are mediated remain poorly understood. In this paper we demonstrate a link between clutch size and escape take‐off speed in small birds, mediated through changes in flight muscle volume during laying.

In a series of experiments the same adult female zebra finches (Taeniopygia guttata) were made to lay both large and small clutches. When producing the larger clutches, females lost more flight muscle condition and became significantly slower to take off during escape flights.

This reduction in take‐off speed with increased egg production was evident after the last egg was laid, and was independent of changes in body mass, so was not simply due to the presence of the eggs inside the female.

This indicates that there is a trade‐off between fecundity and the maintenance of somatic musculature critical to an animal’s escape response. As changes in take‐off speed can have disproportionate effects on the chances of ground‐feeding birds surviving a predatory attack, the degree of reduction in flight muscle condition during laying could be a constraint on clutch sizes in such birds.
Effects of intra‐ and interspecific interactions on species responses to environmental change
Authors: Jeremy W. Fox , Peter J. Morin
Published: September 2010

The extent of directional environmental change expected in the next century underscores the need to understand density‐dependent population regulation.

Direct density dependence generated by intraspecific competition and/or predator–prey interactions should buffer environmentally produced changes in density‐independent growth rates (r). Density dependence generated by interspecific competition should magnify sensitivity to changes in r.

We tested these predictions by assembling protist communities in laboratory microcosms and subjecting the communities to directional environmental change. Two experiments used pairs of competing protists (Colpidium striatum Stein and Tetrahymena thermophila Nanney & McCoy, and Paramecium tetraurelia Sonneborn and Blepharisma americanum Suzuki) along with single‐species controls. Two experiments used predator–prey pairs (Didinium nasutum Müller or Euplotes patella Ehrenberg preying on Colpidium) and controls containing only prey. We grew replicates of each species combination in two temperature regimes (constant or slowly increasing temperature). Independent of these experiments, we quantified the temperature dependence of r (intrinsic rate of increase) for each species.

Comparison of effects of temperature on r to effects on mean density revealed that intraspecific competition buffered species densities against temperature changes that increased r by over 200%. Interspecific interactions did not affect species responses to environmental change. Temperature change had weak effects on species densities, whether or not other species were present.

The results suggest that natural populations, regulated by direct density dependence, may be buffered against directional environmental change. Environmental change will have large effects when populations experience little density dependence, and when environmental change has different effects on the vital rates of different species.