bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of increased temperature and nutrient enrichment on the stoichiometry of primary producers and consumers in temperate shallow lakes
Authors: VENTURA M. , LIBORIUSSEN L. , LAURIDSEN T. , SØNDERGAARD M. , SØNDERGAARD M. , JEPPESEN E. 
Published: February 2008

Summary1. We studied the effects of increased water temperatures (0–4.5 °C) and nutrient enrichment on the stoichiometric composition of different primary producers (macrophytes, epiphytes, seston and sediment biofilm) and invertebrate consumers in 24 mesocosm ecosystems created to mimic shallow pond environments. The nutrient ratios of primary producers were used as indicative of relative nitrogen (N) or phosphorus (P) limitation. We further used carbon stable isotopic composition (δ13C) of the different primary producers to elucidate differences in the degree of CO2 limitation.2. Epiphytes were the only primary producer with significantly higher δ13C in the enriched mesocosms. No temperature effects were observed in δ13C composition of any primary producer. Independently of the treatment effects, the four primary producers had different δ13C signatures indicative of differences in CO2 limitation. Seston had signatures indicating negligible or low CO2 limitation, followed by epiphytes and sediment biofilm, with moderate CO2 limitation, while macrophytes showed the strongest CO2 limitation. CO2 together with biomass of epiphytes were the key variables explaining between 50 and 70% of the variability in δ13C of the different primary producers, suggesting that epiphytes play an important role in carbon flow of temperate shallow lakes.3. The ratio of carbon to chlorophyll a decreased with increasing temperature and enrichment in both epiphytes and seston. The effects of temperature were mainly attributed to changes in algal Chl a content, while the decrease with enrichment was probably a result of a higher proportion of algae in the seston and epiphytes.4. Macrophytes, epiphytes and seston decreased their C : N with enrichment, probably as an adaptation to the different N availability levels. The C : N of epiphytes and Elodea canadensis decreased with increasing temperature in the control mesocosms. Sediment biofilm was the only primary producer with lower C : P and N : P with enrichment, probably as a result of higher P accumulation in the sediment.5. Independently of nutrient level and increased temperature effects the four primary producers had significantly different stoichiometric compositions. Macrophytes had higher C : N and C : P and, together with epiphytes, also the highest N : P. Seston had no N or P limitation, while macrophytes and epiphytes may have been P limited in a few mesocosms. Sediment biofilm indicated strong N deficiency.6. Consumers had strongly homeostatic stoichiometric compositions in comparison to primary producers, with weak or no significant treatment effects in any of the groups (insects, leeches, molluscs and crustaceans). Among consumers, predators had significantly higher N content and lower C : N than grazers.
Canal preparation using only one Ni‐Ti rotary instrument: preliminary observations
Authors: Yared G. 
Published: February 2008

AbstractAim  To describe a novel canal preparation technique using only one Ni‐Ti rotary instrument.Summary  In this novel technique, the canal is negotiated to the working length with a size 08 hand file. Then, the canal preparation is completed with an F2 ProTaper instrument used in a reciprocating movement. In larger canals, the use of additional hand files may be required to complete the apical enlargement.Key learning points

A novel canal preparation technique is introduced using only one Ni‐Ti rotary instrument in a reciprocating movement.
The advantages of the technique include a reduced number of instruments, lower cost, a reduced instrument fatigue and the elimination of possible prion cross‐contamination associated with the single use of endodontic instruments.
Degradation of trans‐polyisoprene after root filling with thermoplasticized techniques
Authors: Maniglia‐Ferreira C. , Bönecker G. , Silva J. B. A. , De Paula R. C. M. , Feitosa J. P. A. , Souza‐Filho F. J. 
Published: February 2008

AbstractAim  To evaluate ex vivo degradation of gutta‐percha following six thermoplastic obturation techniques.Methodology  Ninety human‐extracted mandibular premolars were selected and divided randomly into nine groups for filling. Group 1: thermomechanical compaction for 3 s with Konne gutta‐percha points (Konne Ind. e Com. de Mat. Odontol., Belo Horizonte, MG, Brazil); Group 2: thermomechanical compaction for 3 s with Dentsply TP gutta‐percha points (Dentsply Indústria e Comércio Ltda, Petrópolis, R.J. Brazil); Group 3: thermomechanical compaction for 10 s with Konne; Group 4: thermomechanical compaction for 10 s with Dentsply TP; Group 5: warm vertical condensation using System B (EIE/Analytic, Richmond, WA, USA) with Konne; Group 6: warm vertical condensation using System B with Dentsply TP; Group 7: vertical condensation with Konne; Group 8: vertical condensation with Dentsply TP; Group 9: Microseal cone (Analytic Endodontics, Glendora, CA, USA). A further four groups were assessed without using teeth, Group 10: Microseal microflow (Analytic Endodontics); Group 11: Obtura (Obtura Corporation, Penton, MO, USA); Group 12: Obtura flow (Obtura Corporation); Group 13: Thermafil (Dentsply Maillefer, Tulsa, OK, USA). The filling material was removed from the root canal and trans‐1,4‐polyisoprene isolated by solubilization of the root filling remnants in chloroform followed by filtration and centrifugation. By gel permeation chromatography and infrared spectroscopy, the occurrence and degree of degradation were assessed. The results were analysed statistically using the Kruskal–Wallis test. With differential scanning calorimetry, the thermal behaviour of the gutta‐percha was determined.Results  A significant decrease in polymer molar mass and the production of carboxyl and hydroxyl groups in the polymer were observed with thermomechanical compaction used for 10 s and vertical condensation filling techniques (P = 0.0001 and P = 0.0005, respectively). Other techniques caused no polymer degradation.Conclusion  Polyisoprene degrades with high temperature. Thermomechanical compaction for 10 s and vertical condensation were associated with the greatest degradative process.
Replantation of three avulsed permanent incisors with complicated crown fractures
Authors: Walter C. , Krastl G. , Izquierdo A. , Hecker H. , Weiger R. 
Published: February 2008

AbstractAim  To report a rare case of multiple avulsions of permanent teeth associated with complicated crown fractures.Summary  The case describes a 3‐year follow‐up of the treatment of three avulsed maxillary incisors with complicated crown fractures. The teeth were replanted after an extra‐oral time of 90 min (extra‐oral dry time 6 min). After root canal treatment, the fractured maxillary incisors were restored with a layered hybrid composite material to re‐establish aesthetics and function. Follow‐up visits showed signs of replacement resorption affecting the maxillary central incisors but only minor signs of root resorption on the maxillary right lateral incisor. These findings were supported by digital volume tomography, which was performed 18 and 36 months post‐trauma in order to assess extent, severity and progression of root resorption more accurately.Key learning points

Healing of avulsed teeth depends on the degree of periodontal ligament (PDL) damage.
Digital volume tomography might improve diagnostics of root resorption.
Influence of surface remodelling using burs on the macro and micro surface morphology of anatomically formed fibre posts
Authors: Plotino G. , Grande N. M. , Pameijer C. H. , Somma F. 
Published: February 2008

AbstractAim  To evaluate the effect of modifying preformed fibre‐reinforced composite (FRC) endodontic posts on their surface morphology and to determine how this procedure affects the integrity of the posts.Summary  Surfaces of 10 preformed glass‐fibre posts (group 1) and carbon‐fibre posts (group 2) were compared with those of individually formed glass‐fibre posts (group 3). Ten FRC posts were modelled in order to give them a shape as close as possible to the anatomy of oval root canals. Starting from a preformed cylindrical fibre post 2.5 mm in diameter, it was modelled in such a way as to passively occupy the entire post‐space length, using a cast previously created as a guide. Microscopic analyses (optical stereomicroscope and scanning electron microscope) of the post surfaces revealed similar features in all three groups. All posts had regular surfaces after cutting with a diamond bur. Smear layer mainly attributable to the cutting procedures covered the cut surface of some specimens. In conclusion, modulation of a fibre post using a diamond‐coated bur did not show a loss of integrity of the post.Key learning points

Because of the importance of micromechanical retention, the surface integrity of fibre posts may be important for adhesion between post and composite resin.
Modification of a fibre post using a diamond‐coated bur did not damage the surface integrity of the posts.
Fibre posts can be ground to a different shape without losing their surface integrity, resulting in posts with a surface that is not visibly different from unmodified commercially available fibre posts.
The influence of grazing intensity and landscape composition on the diversity and abundance of flower‐visiting insects
Authors: Sjödin N. Erik , Bengtsson Jan , Ekbom Barbara 
Published: February 2008

Summary

The loss of semi‐natural grasslands in agro‐ecosystems has increased the importance of adequate management of remaining grasslands. Recommendations for intensive grazing have been debated because the effects of different management practices may differ between taxa and species. The increased fragmentation of grasslands suggests that the influence of management practices should be studied in a landscape context.
We studied four groups of flower visitors, many of which are pollinators, bees (Apoidea), butterflies (Lepidoptera), hoverflies (Syrphidae) and beetles (Coleoptera), in semi‐natural grasslands managed at three intensity levels in eight areas in central Sweden. Local characteristics of the grasslands were recorded and landscape diversity was quantified. Vegetation height was correlated with grazing intensity: intensive grazing with the shortest vegetation and abandoned grassland with the tallest.
The insect groups responded differently to grazing intensity. Species richness and abundance differed between management regimes for beetles and hoverflies but not for bees and butterflies.
The effects of local habitat and landscape composition on species richness, abundance and composition differed between groups. Bee diversity responded to both local and landscape factors. Butterflies were mainly affected by local vegetation height and linear elements in the landscape. More species of hoverflies were recorded in tall vegetation and in landscapes with high forest cover. Beetles responded only to local environment characteristics.
Synthesis and applications. We demonstrate the importance of studying different insect groups simultaneously when evaluating habitat and landscape qualities for diversity. The results suggest that planning for conservation of biodiversity at landscape scales may be better than implementing grazing guidelines for individual grasslands. Grazing intensity should vary within or between landscapes to preserve pollinator diversity. Conservation management to encourage flower visitors cannot be generalized to include all groups simultaneously.
Bayesian modelling procedures for the evaluation of changes in wildlife habitat suitability: a case study of roe deer in the Italian Alps
Authors: Morgia Valentina La , Bona Francesca , Badino Guido 
Published: February 2008

Summary

Combining species protection with land management is a central concern for nature conservation but requires a collaborative, problem‐solving approach. Existing procedures do not guarantee the participation of stakeholders in the decision‐making process and, thus, do not necessarily support the development of acceptable management strategies. An analytical framework is required to assess the consequences of human land use for wildlife habitats, incorporating a quantitative structure for including stakeholder opinions. We provide such a framework.
As an example, we used the procedure to evaluate the consequences of different building scenarios for the Turin 2006 Winter Olympic Games on potential roe deer Capreolus capreolus habitats. The analysis involved four steps: (i) three Bayesian models were developed to assess the suitability of six study areas for roe deer; (ii) the outcome of the models was converted into a habitat suitability index (HSI) for each study area; (iii) for each area, the building scenario chosen by the Olympic Games organizers was compared with alternative scenarios by means of HSI values; (iv) an HSI value was chosen as a benchmark to evaluate the ecological consequences of landscape changes.
The building projects chosen by the Olympic Games organizers caused changes in HSI values in each study area, especially at one site. In three of the six study areas, the chosen projects minimized the loss of suitable roe deer habitat, while in the remaining areas the alternative building locations could have reduced the negative consequences of human activities.
Synthesis and applications. A habitat suitablility index calculated with our procedure can be used to (i) compare different hypothetical land‐use scenarios and make decisions about the location of human infrastructures to minimize habitat loss; and (ii) assess the consequences of human activities in relation to an ecological benchmark. The Bayesian approach provides a way to involve local stakeholders in the decision‐making process, and thus is a useful tool for discussion of land‐use policies. Our procedure could be applied to rare and common species and to assessing the consequences of all human activities involving reductions in natural habitat.
Direct visualization of the dynamics of membrane‐anchor proteins in living cells
Authors: WANG C. , FU G. , WANG J. , WANG G. , CHENG Y. , XU Z.‐Z. 
Published: February 2008

SummaryDynamic properties of proteins have crucial roles in understanding protein function and molecular mechanism within cells. In this paper, we combined total internal reflection fluorescence microscopy with oblique illumination fluorescence microscopy to observe directly the movement and localization of membrane‐anchored green fluorescence proteins in living cells. Total internal reflect illumination allowed the observation of proteins in the cell membrane of living cells since the penetrate depth could be adjusted to about 80 nm, and oblique illumination allowed the observation of proteins both in the cytoplasm and apical membrane, which made this combination a promising tool to investigate the dynamics of proteins through the whole cell. Not only individual protein molecule tracks have been analyzed quantitatively but also cumulative probability distribution function analysis of ensemble trajectories has been done to reveal the mobility of proteins. Finally, single particle tracking has acted as a compensation for single molecule tracking. All the results exhibited green fluorescence protein dynamics within cytoplasm, on the membrane and from cytoplasm to plasma membrane.
New controlled environment vitrification system for preparing wet samples for cryo‐SEM
Authors: GE H. , SUSZYNSKI W. J. , DAVIS H. T. , SCRIVEN L. E. 
Published: February 2008

SummaryA new controlled environment vitrification system (CEVS) has been designed and constructed to facilitate examination by cryogenic scanning electron microscopy (Cryo‐SEM) of initial suspension state and of microstructure development in latex, latex–composite and other coatings while they still contain solvent. The new system has a main chamber with provisions for coating as well as drying, and for well‐controlled plunging into cryogen. An added subsidiary chamber holds samples for drying or annealing over minutes to days before they are returned to the main chamber and plunged from it. In the main chamber, samples are blade‐coated on 5 × 7 mm pieces of silicon wafer and held at selected temperature and humidity for successively longer times, either there or after transfer along a rail into the subsidiary chamber. They are then placed in the sample holder mounted on the plunge rod, so as to permit adjustment of the sample's attitude when it plunges, at controlled speed, into liquid ethane at its freezing point, to a chosen depth, in order to solidify the sample without significant shear or freezing artifacts. The entries of plunging samples and related sample holders into liquid ethane were recorded with a high‐speed, high‐resolution Photron digital camera. The data were interpreted with a new hypothesis about the width of the band of extremely rapid cooling by deeply subcooled nucleate boiling below the line of entry. Complementary cryo‐SEM images revealed that the freezing rate and surface shearing of a sample need to be balanced by adjusting the plunging attitude.
Scanning‐less wide‐field single‐photon counting device for fluorescence intensity, lifetime and time‐resolved anisotropy imaging microscopy
Authors: SPITZ J.‐A. , YASUKUNI R. , SANDEAU N. , TAKANO M. , VACHON J.‐J. , MEALLET‐RENAULT R. , PANSU R.B. 
Published: February 2008

SummaryA scanning‐less single‐photon counting system for FLIM and fluorescence anisotropy wide‐field imaging is described and characterized in this paper. The two polarizations of the fluorescence are divided by a Glan prism and acquired at the same time by the QA detector. Fluorescence decay profiles can be reconstructed for any desired area up to each pixel and used to calculate time‐resolved fluorescence anisotropy decays.
Measuring the velocity of fluorescently labelled red blood cells with a keyhole tracking algorithm
Authors: REYES‐ALDASORO C. C. , AKERMAN S. , TOZER G. M. 
Published: February 2008

SummaryIn this paper we propose a tracking algorithm to measure the velocity of fluorescently labelled red blood cells travelling through microvessels of tumours, growing in dorsal skin flap window chambers, implanted on mice. Preprocessing removed noise and artefacts from the images and then segmented cells from background. The tracking algorithm is based on a ‘keyhole’ model that describes the probable movement of a segmented cell between contiguous frames of a video sequence. When a history of cell movement exists, past, present and a predicted landing position of the cells will define two regions of probability that resemble the shape of a keyhole. This keyhole model was used to determine if cells in contiguous frames should be linked to form tracks and also as a postprocessing tool to join split tracks and discard links that could have been formed due to noise or uncertainty. When there was no history, a circular region around the centroid of the parent cell was used as a region of probability. Outliers were removed based on the distribution of the average velocities of the tracks. Since the position and time of each cell is recorded, a wealth of statistical measures can be obtained from the tracks. The algorithm was tested on two sets of experiments. First, the vasculatures of eight tumours with different geometries were analyzed; average velocities ranged from 86 to 372 μm s−1, with minimum and maximum track velocities 7 and 1212 μm s−1, respectively. Second, a longitudinal study of velocities was performed after administering a vascular disrupting agent to two tumours and the time behaviour was analyzed over 24 h. In one of the tumours there is a complete shutdown of the vasculature whereas in the other there is a clear decrease of velocity at 30 min, with subsequent recovery by 6 h. The tracking algorithm enabled the simultaneous measurement of red blood cell velocity in multiple vessels within an intravital video sequence, enabling analysis of heterogeneity of flow and response to treatment in mouse models of cancer.
Analysis of photopolymerized acrylic films by AFM in pulsed force mode
Authors: JRADI S. , SOPPERA O. , LOUGNOT D. J. 
Published: February 2008

SummaryThis paper highlights the potential of atomic force microscopy in the pulsed force mode to investigate the photopatterning of acrylic‐based films. The pulsed force mode is a nonresonant mode designed to allow approach curves to be recorded along the scanning path. It thereby provides the topography of the sample and a direct and simple local characterization of adhesion and stiffness. This mode can be used either for imaging or for locally probing the mechanical properties of a surface. In particular, a correlation between stiffness and conversion of the monomer was established. The close examination of the pulsed force mode signal brought accurate information on the photoinduced modification of the film. Polymer films with submicron photopatterning generated by interferometric illumination were analyzed by pulsed force mode. It was established that the gradient of mechanical properties throughout the films was strongly dependant on the irradiation conditions.
Surface plasmon‐assisted widefield non‐linear imaging of gold structures
Authors: QIAN C. , VELINOV T. S. , PITTER M. C. , SOMEKH M. G. 
Published: February 2008

SummaryIn this paper, we demonstrate how the confinement and enhancement of optical fields by surface plasmon resonance can allow non‐linear microscopy to be performed in a simple, cost‐effective widefield configuration, rather than the more usual laser‐scanning arrangement. We present second harmonic and two‐photon luminescence widefield images of dielectric and gold samples obtained with both prism‐based and high numerical aperture objective (‘prismless’) microscope arrangements.
Concentrated dyes as a source of two‐dimensional fluorescent field for characterization of a confocal microscope
Authors: MODEL M. A. , BLANK J. L. 
Published: February 2008

SummaryThe axial spread function is a useful tool for evaluation of a confocal microscope. It can be obtained experimentally by scanning a uniform fluorescent layer whose thickness is significantly below the resolution limit. Previous researchers have created thin fluorescent films by chemical synthesis. We show here that concentrated fluorescent dyes with a strong absorption at the excitation wavelength can serve as a good approximation of thin fluorescent films. The vertical intensity profiles of such dyes are symmetrical and represent the true axial resolution of a microscope. Solutions of dyes sufficiently opaque to test confocal microscopes with high‐NA objectives can be prepared from sodium fluorescein, acid fuchsin and acid blue 9 for excitation at 488 nm, 543 nm and 633 nm, respectively.