bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of artificial exclusion and augmentation of fungal plant pathogens on a regenerating grassland
Authors: PETERS J. C. , SHAW M. W. 
Published: April 2006

summaryPlots of rough grassland dominated by Holcus lanatus L. were cleared of vegetation in three successive years and allowed to regenerate without grazing or harvesting. Vegetation cover and foliar disease severity were measured using pin sampling in each plot, two to four times per year. One third of plots were sprayed regularly with propiconazole to reduce fungal disease; one third of plots were sprayed with rust (Puccinia coronata f. sp. holci Corda.) urediospores in the second and third years of the study and with conidia of the leaf‐spotting fungus Ascochyta leptospora (Trail) Hara. In the third year. The fungicide had direct effects on the growth of perennial herbs and grasses, and indirect effects through disease control on perennial herbs. Both fungicide treatment and disease augmentation tended to raise diversity in plots where grasses were only partly dominant. Fungicides increased diversity because both direct and indirect effects were greater in perennial herbs than in grasses. Disease augmentation raised diversity because the diseases introduced were more specific to the most common component of the vegetation, H. lanatus.
Effect of 700 μmol mol −1CO2 and infection with powdery mildew on the growth and carbon partitioning of barley
Authors: HIBBERD J. M. , WHITBREAD R. , FARRAR J. F. 
Published: April 2006

summaryThe dry weight of barley plants in 700 μmol mol−1CO2 was increased by 19 d after planting relative to plants grown in 350 μmol mol−1CO2. Infection of the second leaf by powdery mildew led to reduced growth rates in both 350 and 700 μmol mol−1CO2, but the reduction in growth was transitory in 350 μmol mol−1CO2. Neither the allometric coefficient k between shoot and root, nor the leaf weight ratio, was altered by growth in 700 μmol mol−1CO2 or by infection with powdery mildew. The number of tillers produced increased per plant but not per unit d. wt in 700 μmol mol−1CO2. The growth response of barley to increased concentrations of CO2 and/or to infection with powdery mildew was not associated with alterations in net carbon partitioning, so a change in the ratio of photosynthetic to non‐photosynthetic tissue, contributed to neither the growth response of barley to 700 μmol mol−1CO2 nor to infection with powdery mildew. The increase in the growth rate of barley in 700 μmol mol−1CO2 and the reduction in the growth rate after infection occurred at the same time as increased and reduced rates of net photosynthesis respectively.
Vertical patterns of testate amoebae (Protozoa: Rhizopoda) and peat‐forming vegetation on cutover bogs in the Jura, Switzerland
Authors: BUTTLER ALEXANDRE , WARNER BARRY G. , GROSVERNIER PHILIPPE , MATTHEY YVAN 
Published: April 2006

summaryThe spatial and temporal processes of secondary vegetation development on abandoned cutover bog surfaces in the Jura region of northwest Switzerland have been examined. Descriptions of post‐abandonment development of peatland based on the vegetation composition of replacement series from previous studies of vegetation ecology have been confirmed by analysis of testate amoebae (Protozoa) in vertical sequences of secondary peat underlying the most advanced vegetation communities in the series. Recovery of bog habitats to conditions similar to those before cutting was rapid. Testate amoebae show this recovery occurred through several different developmental series, all of which led to a common convergence regardless of the initial condition of the old cutover surface. Cutover bogs can be fully restored and testate amoebae are a sensitive new means of monitoring habitat changes in bogs.
Phragmites die‐back: sulphide‐ and acetic acid‐induced bud and root death, lignifications, and blockages within aeration and vascular systems
Authors: ARMSTRONG J. , AFREEN‐ZOBAYED F. , ARMSTRONG W. 
Published: April 2006

summary Phragmites rhizome cuttings, and plantlets raised from seed, were exposed to the phytotoxins acetic acid or dissolved sulphide in unstirred solution cultures to determine whether die‐back symptoms found in field‐grown plants, and attributed to phytotoxin damage, could be induced. Many of the die‐back symptoms associated with field sites, namely stunted adventitious roots and laterals, bud death, callus blockages of the gas‐pathways, and vascular blockages, were all reproduced, and were particularly acute at the higher concentrations of the phytotoxins: acetic acid (1.67 mm), sulphide (1.4 mm).The results accord with the hypothesis that phytotoxins may play a critical role in Phragmites australis die‐back.
Some foliar characteristics of ash trees (Fraxinus excelsior) exposed to ozone episodes
Authors: WILTSHIRE J. J. J. , WRIGHT C. J. , COLLS J. J. , CRAIGON J. , UNSWORTH M. H. 
Published: April 2006

summaryYoung ash trees (Fraxinus excelsiorL.) growing in the field were exposed to episodes of 150 nl 1−1ozone, or to clean air, in open‐top chambers at the University of Nottingham, Sutton Bonington Campus, UK, May–October, 1992–1994. The episodes were for 8 h daily and for 1–4 d in succession, with seasonal totals of 24–27 d. A nondestructive method for estimating whole‐tree leaf area was developed in 1992 and used to monitor leaf area, leaf number and leaf size in 1993 and 1994. Stomatal density and leaf abscission were also studied. No effects of exposure to ozone on leaf area and leaf number were detected. In 1994 there were consistent trends towards greater mean leaf size and higher stomatal density in trees exposed to ozone, but these effects were not significant at the 95% confidence level. Leaf abscission was slower in trees exposed to ozone in 1992 and 1994, but not in 1993 when there were fewer exposure days late in the season.
TheSauromatum guttatumappendix as an osmophore: excretory pathways, composition of volatiles and attractiveness to insects
Authors: SKUBATZ HANNA , KUNKEL DENNIS D. , HOWALD WILLIAM N. , TRENKLE ROBERT , MOOKHERJEE BRAJA 
Published: April 2006

summaryThis report combines chemical, electron microscopic and ecological studies on the volatiles liberated by theSauromatum guttatumappendix on D‐Day, the day of inflorescence‐opening and heat‐production. More than 100 compounds from at least nine different chemical classes (monoterpenes, sesquiterpenes, fatty acids, ketones, alcohols, aldehydes, indole, and phenolic and sulphur compounds) are liberated during the thermogenic activity. The volatiles were identified using gas chromatography‐mass spectrometry. Electron microscopy provides additional evidence that the endoplasmic reticulum (ER) interacts with the plasma membrane, creating novel routes of excretion of the volatiles to the exterior of the cell. It seems that the fusion event creates channels from the interior to the exterior of the cell. Furthermore, a multitubular body, conceivably originating in the ER, seems to fuse with the plasma membrane and to appear only on D‐day. This multitubular body is closely associated with lipid bodies during heat‐production and might be involved in the oxidation of lipids to volatile products. The foul odour produced by the appendix attracts at least 30 species of insects.
The effects of long‐term elevated ozone concentrations on the growth and photosynthesis of Sphagnum recurvum and Polytrichum commune
Authors: POTTER L. , FOOT J. P. , CAPORN S. J. M. , Lee J. A. 
Published: April 2006

summaryAlthough ozone is generally accepted to be an important phytotoxic air pollutant, little is known of its effects on natural and semi‐natural vegetation. In this study two bryophyte species, Sphagnum recurvum P. Beauv. and Polytrichum commune Hedw., were exposed to long‐term chronic ozone concentrations, i.e. 70–80 ppb (nl 1−1), for 6–9 wk in summer conditions (mean 15°C) and in winter conditions (mean 6.4°C) in open‐top chambers (OTC), in the field, and at 15°C and 5°C in controlled‐environment chambers, under laboratory conditions.Fumigation with ozone caused a significant reduction in the growth of treated plants in comparison with that of control plants. However, there were differences between species. S. recurvum was more affected than P. commune. In the controlled‐environment chambers growth of S. recurvum was reduced under both winter and summer conditions by 21 and 15%, respectively. In the OTCs, S. recurvum growth was reduced (by 17%) only under summer conditions. P. commune growth was only significantly reduced following ozone exposure in the OTCs under winter conditions. Here the growth reduction was by 22%.Net CO2 assimilation of the two species was also significantly reduced by ozone exposure but only in the OTCs under winter conditions. Net CO2 assimilation of S. recurvum and P. commune was reduced by 60 and 80%, respectively.The ratio of variable to maximal fluorescence (Fv/Fm ratio) was the least affected of the parameters measured. Only for P. commune fumigated in the OTCs under winter conditions was the Fv/Fm ratio significantly reduced (by 4.4%).Bryophytes, by the very nature of their morphology and physiology are, perhaps, more likely to be susceptible to ozone pollution than higher plants; these results are discussed in relation to their possible ecological significance.
The effect of different temperatures on the fatty acid composition of Rhizobium leguminosarum bv. viciae in the faba bean symbiosis
Authors: THÉBERGE MARIE‐CLAUDE , PRÉVOST DANIELLE , CHALIFOUR FRANÇOIS‐P. 
Published: April 2006

summaryFatty acid composition was determined in cells of strains CBhS and CBp7 of Rhizobium leguminosarum bv. viciae grown at four temperatures (10, 15, 22 and 30°C), and in bacteroids and nodules formed with faba bean (Vicia faba L.) grown at two day/night temperature regimes (22/15 and 15/10°C). Growth temperature markedly affected the fatty acid composition of free‐living bacteria in both strains studied, and both showed similar variations at each temperature. The proportion of unsaturated fatty acids increased significantly with lowering of temperature. The major fatty acid found in bacteria and bacteroids was cis‐vaccenic (C18: 1Δ11), which comprised up to c. 78 (bacteria) and 56% (bacteroids) of total fatty acids. The presence of polyunsaturated fatty acids (linoleic (C18:Δ,9,12) and linolenic (C18:3Δ9,12,15) acids) was noted only in bacteroids, indicating changes following the differentiation of bacteria into bacteroids in the nodules. The fatty acid composition of nodules was similar to that of bacteroids, although major differences were found in their proportions. The different day/night temperature regimes had contrasting effects in bacteroids and in nodules. In bacteroids of both strains, the proportions of stearic (C18:0) and linoleic (C18:Δ9,12) acids decreased at the lower temperature regime. In nodules, the proportion of stearic (C18:0) acid decreased, while that of linolenic (C18:3Δ9,12,15) acid increased at the lower temperature regime. However, those of cis‐vaccenic (C18:1Δ11), linoleic (C18:Δ9,12,15) and palmitic (C16:0) acids increased or decreased depending on the rhizobial strain. The proportion of unsaturated fatty acids increased with the lowering of temperatures in bacteroids of both strains, and varied in whole nodules depending on the strain. Strain CBp7 showed a greater symbiotic efficiency (dry matter yield) than strain CBh5 under both temperature regimes, but no relationship was found with the proportion of unsaturated fatty acids of bacteria, bacteroids or nodules.
Genetic selection of sox1GFP‐expressing neural precursors removes residual tumorigenic pluripotent stem cells and attenuates tumor formation after transplantation
Authors: Chung S. , Shin B.‐S. , Hedlund E. , Pruszak J. , Ferree A. , Kang Un Jung , Isacson Ole , Kim Kwang‐Soo 
Published: April 2006

AbstractBecause of their ability to proliferate and to differentiate into diverse cell types, embryonic stem (ES) cells are a potential source of cells for transplantation therapy of various diseases, including Parkinson's disease. A critical issue for this potential therapy is the elimination of undifferentiated cells that, even in low numbers, could result in teratoma formation in the host brain. We hypothesize that an efficient solution would consist of purifying the desired cell types, such as neural precursors, prior to transplantation. To test this hypothesis, we differentiated sox1‐green fluorescent protein (GFP) knock‐in ES cells in vitro, purified neural precursor cells by fluorescence‐activated cell sorting (FACS), and characterized the purified cells in vitro as well as in vivo. Immunocytofluorescence and RT‐PCR analyses showed that this genetic purification procedure efficiently removed undifferentiated pluripotent stem cells. Furthermore, when differentiated into mature neurons in vitro, the purified GFP+ cell population generated enriched neuronal populations, whereas the GFP– population generated much fewer neurons. When treated with dopaminergic inducing signals such as sonic hedgehog (SHH) and fibroblast growth factor‐8 (FGF8), FACS‐purified neural precursor cells responded to these molecules and generated dopaminergic neurons as well as other neural subtypes. When transplanted, the GFP+ cell population generated well contained grafts containing dopaminergic neurons, whereas the GFP– population generated significantly larger grafts (about 20‐fold) and frequent tumor‐related deaths in the transplanted animals. Taken together, our results demonstrate that genetic purification of neural precursor cells using FACS isolation can effectively remove unwanted proliferating cell types and avoid tumor formation after transplantation.
Sustained viral response prolonged survival of patients with C‐viral hepatocellular carcinoma
Authors: Akamatsu Masatoshi , Yoshida Haruhiko , Shiina Shuichiro , Teratani Takuma , Obi Shuntaro , Tateishi Ryousuke , Mine Norio , Kondo Yuji , Kawabe Takao , Omata Masao 
Published: April 2006

Abstract: Background: We conducted this retrospective study to evaluate the position of interferon therapy in the curative treatment of hepatitis C virus‐associated hepatocellular carcinoma (HCC).Methods: We compared overall and recurrence‐free survival rates between 191 patients who received interferon therapy before HCC development (15 with sustained virologic response (SVR)), 53 who received interferon therapy after HCC ablation (17 with SVR), and 399 HCC patients with Child–Pugh class A liver function who did not receive interferon (controls).Results: The overall survival rate in the controls was 82.4%, 53.2%, and 28.3% at 3, 6, and 9 years, respectively, whereas that in patients who developed HCC after achieving SVR was 93.3%, 93.3%, and 93.3%; those with HCC after non‐SVR, 87.8%, 56.5%, and 35.8%; SVR after HCC, 100%, 87.5%, and 59.7%; and non‐SVR after HCC, 94.3%, 70.9%, and 53.2%. Cox proportional hazard regression analysis revealed that the risk of death was significantly reduced in patients with HCC after SVR and those with SVR after HCC, with a risk ratio of 0.124 (95% confidence interval (95% CI): 0.017–0.890, P=0.0378) and 0.388 (95% CI: 0.169–0.887, P=0.0250), respectively, compared with the controls. Improved survival was attributable mainly to sustained liver function among patients with SVR, and recurrence‐free survival did not differ significantly.Conclusion: Interferon therapies before and after HCC development were both significantly associated with prolonged survival when SVR was achieved.
The natural history of parallel transjugular intrahepatic portosystemic stent shunts using uncovered stent: the role of host‐related factors
Authors: Helmy Ahmed , Redhead Doris N. , Stanley Adrian J. , Hayes Peter C. 
Published: April 2006

Abstract: Objectives: Parallel shunts (PS) are used in the management of transjugular intrahepatic portosystemic stent‐shunt (TIPS) insufficiency, a major limitation of the technique. This study describes the natural history of PS, and uses them as a model to assess the role of host factors in the development of primary shunt insufficiency.Methods: Out of 338 patients with TIPS, 40 (11.8%) patients required insertion of a PS. Baseline and follow‐up data of these patients were collected. Regular shunt surveillance involved biannual clinic visits and transjugular portography.Results: The non‐PS group (group 1; n=298) and the PS group (group 2; n=40) had similar baseline demographic and disease characteristics. Index shunts of both groups and the PS produced a significant portal pressure gradient drop (P<0.001), which was less in the index shunts of Group 2 (P<0.02 for both). PS had similar cumulative shunt patency rates to those of the index shunts of Group 1, and both were greater than those of index shunts in Group 2 (P<0.001 for both). The intervention rate (number of interventions/number of check portograms × 100) was similar for PS and the index shunts of Group 1 (38.7% and 43% respectively), but was significantly higher in the index shunts of Group 2 (85.6%; P<0.01 for both). In Group 1 and Group 2, 144 patients (48.3%) and 21 patients (52.5%) died during follow‐up after a median period of 23.4 and 8.9 months respectively.Conclusions: These findings do not support the hypothesis that shunt insufficiency is related to host factors.
Activated hepatic stellate cells overexpress p75NTR after partial hepatectomy and undergo apoptosis on nerve growth factor stimulation
Authors: Asai Keiko , Tamakawa Susumu , Yamamoto Masahiro , Yoshie Masumi , Tokusashi Yoshihiko , Yaginuma Yuji , Kasai Shinichi , Ogawa Katsuhiro 
Published: April 2006

Abstract: Background: Expression of neurotrophins (NTs) and their receptors is increased during hepatic regeneration, but their role is not well understood.Methods: NTs and their receptors were investigated by RT‐PCR and immunostaining in regenerating livers after two‐thirds hepatectomy (PH) and in hepatocytes and hepatic stellate cells (HSCs) isolated from regenerating livers in mice. Induction of apoptosis after treatment with NGF and the expression of α‐smooth muscle actin (SMA), interleukin 6 (IL‐6) and hepatocyte growth factor (HGF) were also investigated in regenerating HSCs.Results: Nerve growth factor (NGF) and p75 NT receptor (p75NTR) mRNA were elevated after PH, while other NTs and NT receptors showed no remarkable change. NGF was detected in regenerating hepatocytes, but not in normal hepatocytes. Regenerating HSCs expressed increased p75NTR and SMA in vivo and showed an activated phenotype and the high expression of HGF and IL‐6 in vitro. Enhanced cell death was seen in HSCs, both from normal and regenerating liver, after treatment with NGF.Conclusions: Although activated HSCs may produce the factors that regulate liver regeneration, the de novo NGF production by regenerating hepatocytes may induce the death of activated HSCs via p75NTR, leading to termination of hepatic regeneration.
Preloads Generated with Repeated Tightening in Three Types of Screws Used in Dental Implant Assemblies
Authors: Byrne Declan , Jacobs Stuart , O'Connell Brian , Houston Frank , Claffey Noel 
Published: April 2006

Purpose:
Abutment screw loosening, especially in the case of cemented single tooth restorations, is a cause of implant restoration failure. This study compared three screws (titanium alloy, gold alloy, and gold‐coated) with similar geometry by recording the preload induced when torques of 10, 20, and 35 Ncm were used for fixation.
Materials and Methods: Two abutment types were used—prefabricated preparable abutments and cast‐on abutments. A custom‐designed rig was used to measure preload in the abutment–screw–implant assembly with a strain gauge. Ten screws of each type were sequentially tightened to 10, 20, and 35 Ncm on ten of the two abutment types. The same screws were then loosened and retightened. This procedure was repeated. Thus, each screw was tightened on three occasions to the three insertion torques. A linear regression model was used to analyze the effects on preload values of screw type and abutment type for each of the three insertion torques.
Results: The results indicated that the gold‐coated screw generated the highest preloads for all insertion torques and for each tightening episode. Further analysis focused on the effects of screw type and abutment type for each episode of tightening and for each fixation torque. The gold‐coated screw, fixed to the prefabricated abutment, displayed higher preloads for the first tightening at 10, 20, and 35 Ncm. Conversely, the same screw fixed to the cast‐on abutment showed higher values for the second and third tightening for all fixation torques. All screws showed decay in preload with the number of times tightened. Given the higher preloads generated using the gold‐coated screw with both abutment types, it is more likely that this type of screw will maintain a secure joint when tightened for the second and third time.
Conclusion:
All screw types displayed some decay in preload with repeated tightening, irrespective of abutment type and insertion torque. The gold‐coated screw showed markedly higher preloads for all insertion torques and for all instances of tightening when compared with the uncoated screws.
Pattern of dental caries experience on tooth surfaces in an adult population
Authors: Hopcraft Matthew Scott , Morgan Michael Vivian 
Published: May 2006

Abstract –  Objectives:  To determine the pattern of caries experience across teeth and surfaces in an adult population depending on age and exposure to water fluoridation.Methods:  Between November 2002 and March 2003 a total of 973 subjects aged 17–51 years had a clinical examination using visual and tactile criteria. Subsequent to this examination, bitewing radiographs were taken and viewed separately. Approximal and occlusal surfaces of molars and premolars were examined on the radiographs.Results:  Caries experience was relatively low, with mean DMFS scores of 3.21, 5.12, 9.61, 13.04 and 24.35 for subjects aged 17–20, 21–25, 26–30, 31–35 and 36–51 years respectively. The first molar teeth had the greatest caries experience, and occlusal surfaces had more caries experience than approximal surfaces. Subjects with a lifetime exposure to fluoridated drinking water had significantly lower caries experience than those who had no exposure to fluoridated drinking water.Conclusion:  This study showed that caries prevalence, although relatively low in the study population, was found predominantly in occlusal surfaces, with an increasing prevalence in approximal surfaces of posterior teeth in older subjects. Subjects with a lifetime exposure to fluoridated drinking water had a lower level of caries experience than those with no exposure to fluoridated drinking water, and this was more noticeable in approximal surfaces than occlusal surfaces.
Social gradients in periodontal diseases among adolescents
Authors: López Rodrigo , Fernández Olaya , Baelum Vibeke 
Published: May 2006

Abstract –  Objective:  To investigate the association between socioeconomic position and periodontal diseases among adolescents.Methods:  Data were obtained from 9203 Chilean high school students. Clinical examinations included direct recordings of clinical attachment level and the necrotizing ulcerative gingival lesions. Students answered a questionnaire on various dimensions of socioeconomic position. Seven periodontal outcomes were analyzed. Logistic regression analyses were used to identify socioeconomic variables associated with the periodontal outcomes.Results:  The occurrence of all periodontal outcomes investigated followed social gradients, and paternal income and parental education were the most influential variables.Conclusions:  The study demonstrates the existence of significant social gradients in periodontal diseases already among adolescents. This is worrying, and indicates a new potential for further insight into the mechanisms of periodontal disease causation.