bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peri‐implant soft‐tissue health surrounding cement‐ and screw‐retained implant restorations: a multi‐center, 3‐year prospective study
Authors: Weber Hans P. , Kim David M. , Ng Mavis W. , Hwang Jae W. , Fiorellini Joseph P. 
Published: June 2006

AbstractObjective: The purpose of this prospective clinical study was to evaluate peri‐implant soft‐tissue conditions and esthetic fulfillment during a 3‐year follow‐up period following prosthetic rehabilitation.Material and methods: As part of a prospective multi‐center study, 152 ITI dental implants were placed in 80 patients in the maxillary anterior region. Fifty‐nine crowns (38.82%) were cement retained, while 93 (61.18%) crowns were screw retained. At loading and 3, 6, 12 and 36 months post‐loading, modified plaque index (MPI), sulcus bleeding index (SBI), keratinized mucosa (KM), gingival level (GL), and esthetic fulfillment were recorded.Results: All patients completed the study and no complications were reported. While statistically not significant at all time points, cement‐retained crowns seemed to present a worsening trend in MPI and SBI scores. Interestingly, screw‐retained crowns seemed to present an opposite picture, their MPI and SBI scores improved over time. While plaque accumulation, prophylaxis and depth of crown margin significantly affected levels of sulcus bleeding, prophylaxis alone played a key role in reducing plaque accumulation. No soft tissue recession was observed in either cement‐ or screw‐retained crowns up to 3 years post‐loading. Esthetic fulfillment survey revealed that patients did not have a preference for crown types; however, dentists favored cement‐retained over screw‐retained crowns.Conclusions: Peri‐implant soft tissues responded more favorably to screw‐retained crowns when compared with cement‐retained crowns. However, no soft‐tissue recession was observed in either type of crowns. Cement‐retained crowns were preferred by dentists, while patients were equally satisfied with either type of crowns they received.
Does rotational strain at screw tightening affect the attainment or maintenance of osseointegration?
Authors: Moriya Katsunori , Maruo Yukinori , Minagi Shogo 
Published: June 2006

AbstractObjectives: This study investigated whether rotational strain affects osseointegration.Material and Methods: A total of 135 male rats were divided into five groups: 2‐w rotation, 4‐w rotation, 8‐w rotation, 12‐w rotation and control. Two hundred and seventy implants were inserted in rat tibia. The control group received no strain, while the 2‐w, 4‐w, 8‐w and 12‐w rotation groups received rotational strain at 2, 4, 8 and 12 weeks after implant placement, respectively. Removal torque (N cm) was measured in vivo. Bone contact rate (%) was calculated histomorphologically. Immunostaining for osteonectin (ON), osteopontin (OPN) and osteocalcin (OCN) was performed. The removal torque and bone contact rate were analyzed using one‐way analyses of variance and the Scheffé method.Results: At 4 weeks, the torque was significantly higher in the 2‐w rotation group (1.30±0.44 N cm) than in the control group (0.79±0.67 N cm). From 8 to 16 weeks, the strained groups showed no significant differences from the control group. From the bone contact rates, bone formation was larger in the 4‐week rotation group (62.9±10.7%) than in the control group (42.1±17.9%) at 8 weeks. The 4‐week rotation group showed higher bone contact rate (61.1±11.3%) compared with the other strained groups and maintained this higher value until 16 weeks, showing no significant difference from the control group (72±5.2%). At the implant–bone interface, OPN was widely distributed and OCN was detected at a low level; however, ON could not be observed in any group.Conclusions: The bone contact rate changed when rotational strain was exerted at different periods after implant placement. However, the removal torque and distribution of extracellular matrix proteins were not adversely affected by the rotational strain.
IL‐1RN gene polymorphism is associated with peri‐implantitis
Authors: Laine Marja L. , Leonhardt Åsa , Roos‐Jansåker Ann‐Marie , Peña A. Salvador , Van Winkelhoff Arie Jan , Winkel Edwin G. , Renvert Stefan 
Published: June 2006

AbstractObjectives: Interleukin (IL)‐1α, IL‐1β and their natural specific inhibitor IL‐1 receptor antagonist (IL‐1ra) play a key role in the regulation of the inflammatory response in periodontal tissues. Polymorphisms in the IL‐1 gene cluster have been associated with severe adult periodontitis. We aimed to investigate the IL‐1 gene cluster polymorphisms in patients with peri‐implantitis.Material and methods: The study included 120 North Caucasian individuals. A total of 71 patients (mean age 68 years, 76% smokers) demonstrating peri‐implantitis at one or more implants as evidenced by bleeding and/or pus on probing and bone loss amounting to >3 threads on Brånemark implants and 49 controls (mean age 66 years, 45% smokers) with clinical healthy mucosa and no bone loss around the implants were recruited for the study. The titanium implants, ad modum Brånemark, had been in function for at least 2 years. Mouthwash samples were collected and used for genotyping of the bi‐allelic polymorphisms IL‐1A−889, IL‐1B+3953, IL‐1B−511 and a variable number of tandem repeat IL‐1RN gene polymorphisms using PCR technique.Results: Significant differences were found in the carriage rate of allele 2 in the IL‐1RN gene between peri‐implantitis patients and controls (56.5% vs. 33.3%, respectively; odds ratios (OR) 2.6; 95% confidence interval (CI) 1.2–5.6; P=0.015). Logistic regression analysis taking smoking, gender and age into account confirmed the association between the IL‐1RN allele 2 carriers and peri‐implantitis (OR 3; 95% CI 1.2–7.6; P=0.02).Conclusions: Our results provide evidence that IL‐1RN gene polymorphism is associated with peri‐implantitis and may represent a risk factor for this disease.
The effect of enamel matrix proteins and deproteinized bovine bone mineral on heterotopic bone formation
Authors: Donos Nikolaos , Kostopoulos Lambros , Tonetti Maurizio , Karring Thorkild , Lang Niklaus P. 
Published: June 2006

AbstractAim: To evaluate the osteoinductive potential of deproteinized bovine bone mineral (DBBM) and an enamel matrix derivative (EMD) in the muscle of rats.Material and methods: Sixteen rats were used in this study. The animals were divided in three groups. Group A: a pouch was created in one of the pectoralis profundis muscles of the thorax of the rats and DBBM particles (Bio‐Oss®) were placed into the pouch. Healing: 60 days. Group B: a small pouch was created on both pectoralis profundis muscles at each side of the thorax midline. In one side, a mixture of EMD (Emdogain®) mixed with DBBM was placed into one of the pouches, whereas in the contralateral side of the thorax the pouch was implanted with DBBM mixed with the propylene glycol alginate (PGA – carrier for enamel matrix proteins of EMD). Healing: 60 days. Group C: the same procedure as group B, but with a healing period of 120 days. Qualitative histological analysis of the results was performed.Results: At 60 days, the histological appearance of the DBBM particles implanted alone was similar to that of the particles implanted together with EMD or PGA at both 60 and 120 days. The DBBM particles were encapsulated into a connective tissue stroma and an inflammatory infiltrate. At 120 days, the DBBM particles implanted together with EMD or PGA exhibited the presence of resorption lacunae in some cases. Intramuscular bone formation was not encountered in any group.Conclusion: The implantation of DBBM particles alone, combined with EMD or its carrier (PGA) failed to exhibit extraskeletal, bone‐inductive properties.
Evaluation of low flow estimation techniques for ungauged catchments
Authors: Patel Junaid A. 
Published: June 2006

AbstractLow flow indices are of interest for a number of water‐related applications. Conventionally, low flow indices are derived from continuous streamflow data; however, these data may not always be available for analysis. A number of techniques have therefore been developed for low flow estimation in ungauged catchments. These approaches vary in complexity and in the amount of initial data required to generate the low flow model. In the UK, software is available which assists in low flow estimation for ungauged catchments. However, certain desktop studies only require a simple evaluation of low flows, with specific low flow indices, such as the Q95 index, being of interest. In this case, the use of such software may not be justified or required in the first instance. This paper demonstrates that a simple regression model is adequate for low flow estimation for multisite analysis where the order magnitude of the low flow index is of importance.
Complete Cap 4 Formation Is Not Required for Viability inTrypanosoma brucei
Authors: Zamudio Jesse R. , Mittra Bidyottam , Zeiner Gusti M. , Feder Marcin , Bujnicki Janusz M. , Sturm Nancy R. , Campbell David A. 
Published: June 2006

ABSTRACTIn kinetoplastids spliced leader (SL) RNA istrans-spliced onto the 5′ ends of all nuclear mRNAs, providing a universal exon with a unique cap. Mature SL contains an m7G cap, ribose 2′-O methylations on the first four nucleotides, and base methylations on nucleotides 1 and 4 (AACU). This structure is referred to as cap 4. Mutagenized SL RNAs that exhibit reduced cap 4 aretrans-spliced, but these mRNAs do not associate with polysomes, suggesting a direct role in translation for cap 4, the primary SL sequence, or both. To separate SL RNA sequence alterations from cap 4 maturation, we have examined two ribose 2′-O-methyltransferases inTrypanosoma brucei. Both enzymes fall into the Rossmann fold class of methyltransferases and model into a conserved structure based on vaccinia virus homolog VP39. Knockdown of the methyltransferases individually or in combination did not affect growth rates and suggests a temporal placement in the cap 4 formation cascade: TbMT417 modifies A2and is not required for subsequent steps; TbMT511 methylates C3, without which U4methylations are reduced. Incomplete cap 4 maturation was reflected in substrate SL and mRNA populations. Recombinant methyltransferases bind to a methyl donor and show preference for m7G-capped RNAs in vitro. Both enzymes reside in the nucleoplasm. Based on the cap phenotype of substrate SL stranded in the cytosol, A2, C3, and U4methylations are added after nuclear reimport of Sm protein-complexed substrate SL RNA. As mature cap 4 is dispensable for translation, cap 1 modifications and/or SL sequences are implicated in ribosomal interaction.
Hypovirus Papain-Like Protease p29 Suppresses RNA Silencing in the Natural Fungal Host and in a Heterologous Plant System
Authors: Segers Gerrit C. , van Wezel Rene , Zhang Xuemei , Hong Yiguo , Nuss Donald L. 
Published: June 2006

ABSTRACTVirulence-attenuating hypoviruses of the speciesCryphonectriahypovirus 1 (CHV1) encode a papain-like protease, p29, that shares similarities with the potyvirus-encoded suppressor of RNA silencing HC-Pro. We now report that hypovirus CHV1-EP713-encoded p29 can suppress RNA silencing in the natural host, the chestnut blight fungusCryphonectria parasitica. Hairpin RNA-triggered silencing was suppressed inC. parasiticastrains expressing p29, and transformation of a transgenic green fluorescent protein (GFP)-silenced strain with p29 resulted in an increased number of transformants with elevated GFP expression levels. The CHV1-EP713 p29 protein was also shown to suppress both virus-induced and agroinfiltration-induced RNA silencing and systemic spread of silencing in GFP-expressing transgenicNicotiana benthamianaline 16c plants. The demonstration that a mycovirus encodes a suppressor of RNA silencing provides circumstantial evidence that RNA silencing in fungi may serve as an antiviral defense mechanism. The observation that a phylogenetically conserved protein of related plant and fungal viruses functions as a suppressor of RNA silencing in both fungi and plants indicates a level of conservation of the mechanisms underlying RNA silencing in these two groups of organisms.
Nature of the Periplastidial Pathway of Starch Synthesis in the CryptophyteGuillardia theta
Authors: Deschamps Philippe , Haferkamp Ilka , Dauvillée David , Haebel Sophie , Steup Martin , Buléon Alain , Putaux Jean-Luc , Colleoni Christophe , d'Hulst Christophe , Plancke Charlotte , Gould Sven , Maier Uwe , Neuhaus H. Ekkehard , Ball Steven 
Published: June 2006

ABSTRACTThe nature of the periplastidial pathway of starch biosynthesis was investigated with the model cryptophyteGuillardia theta. The storage polysaccharide granules were shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization very similar to those of starch from green algae and land plants. Most starch granules displayed a shape consistent with biosynthesis occurring around the pyrenoid through the rhodoplast membranes. A protein with significant similarity to the amylose-synthesizing granule-bound starch synthase 1 from green plants was found as the major polypeptide bound to the polysaccharide matrix. N-terminal sequencing of the mature protein proved that the precursor protein carries a nonfunctional transit peptide in its bipartite topogenic signal sequence which is cleaved without yielding transport of the enzyme across the two inner plastid membranes. The enzyme was shown to display similar affinities for ADP and UDP-glucose, while theVmaxmeasured with UDP-glucose was twofold higher. The granule-bound starch synthase fromGuillardia thetawas demonstrated to be responsible for the synthesis of long glucan chains and therefore to be the functional equivalent of the amylose-synthesizing enzyme of green plants. Preliminary characterization of the starch pathway suggests thatGuillardia thetautilizes a UDP-glucose-based pathway to synthesize starch.
Freezing in nonacclimated oat: thermal response and histological observations of crowns during recovery
Authors: Livingston David P. , Tallury Shyamalrau P. , A. Owens Shirley , Livingston Jesse D. , Premkumar Ramaswamy 
Published: June 2006

The complex nature of freezing in plants may be easier to understand if freezing is studied in nonacclimated plants at temperatures just below freezing. Thermal patterns of model systems frozen at –2.6 °C were compared with those of crown tissue from oat ( Avena sativa L.). Thermal patterns of live crowns more closely resembled those of fructan and sugar solutions with filter paper than of plain water or a BSA solution. When the percentage of water freezing in nonacclimated plants at –2.6 °C was manually limited to 10%, the survival was reduced from 100% in supercooled plants to 25%. During cold acclimation, the percentage of water freezing at –2.6 °C went from 79% to 54% after 3 weeks of cold acclimation and resulted in 100% survival. The nucleus of cells in the primary apical meristem of nonacclimated plants appeared to have disintegrated, an effect that was not observed in any cold-acclimated (unfrozen controls) plants. Nuclear pycnosis was observed in leaf sheaths surrounding the meristem and in cells directly below the meristem. Cells of secondary meristems and in the crown core appeared undamaged, but vessels in plants frozen for as little as 30 min were ruptured and appeared plugged. The distinctive nature of injury in the apical meristem and the rapid ability of the plant to acclimate during cold to the stress causing this injury indicate that specific tissue, namely the apical region of the crown, should be the focus of attention when attempting to determine cause and effect between genetics or metabolism and cold acclimation in winter cereals.
The biotransformation of mercury in pH-stat cultures of microfungi
Authors: Kelly David J.A. , Budd Kenneth , Lefebvre Daniel D. 
Published: June 2006

The biotransformation of mercury was monitored in Hymenoscyphus ericae (Read) Korf & Kernan, Neocosmospora vasinfecta E. F. Sm., and Verticillium terrestre (Link) Lindau following the exposure of these fungi to environmentally relevant doses of HgII(HgCl2) in aerated pH-controlled cultures. Mercury applied at 120 and 300 μg·L–1quickly associated with cells of N. vasinfecta. Within 3 h, approximately 80% of the remaining Hg in both treatments had been converted to β-HgS, and at 8 h, 15% and 53% of the original doses had been converted into volatile Hg0. Hymenoscyphus ericae was less efficient at converting HgIIto β-HgS, but it volatilized larger amounts of Hg0. A mercury-tolerant isolate of V. terrestre withstood levels of Hg in the parts per million. When exposed to 270, 1000, or 2000 μg·L–1HgCl2, 93% ± 3% of the amounts remaining in cultures of V. terrestre after 2 h was β-HgS. At 2 mg·L–1, 72% of the Hg was reduced to Hg0in 2 h. Volatilization accounts for the tolerance of V. terrestre to high doses of Hg, whereas the conversion of Hg to β-HgS was the major detoxifying mechanism at lower doses. The formation of β-HgS occurs preferentially with volatilization operating as the default pathway, when the former biotransformation mechanism is saturated.
Association of Gluconacetobacter diazotrophicus with roots of common bean (Phaseolus vulgaris) seedlings is promoted in vitro by UV light
Authors: Trujillo-López Alejandra , Camargo-Zendejas Oscar , Salgado-Garciglia Rafael , Cano-Camacho Horacio , Baizabal-Aguirre Víctor M. , Ochoa-Zarzosa Alejandra , López-Meza Joel E. , Valdez-Alarcón Juan J. 
Published: June 2006

Gluconacetobacter diazotrophicus is a diazotrophic endophyte that is a potential biofertilizer. Little is known about the mechanisms of G. diazotrophicus interaction with its host plants. We tested the effect of UV light, as an inducer of secondary metabolite accumulation, on the association between common bean ( Phaseolus vulgaris L.) seedling roots and G. diazotrophicus. UV light irradiation of seedlings 4 h prior to bacterial inoculation increased the number of bacterial cells associated with the roots by 5.65-fold with respect to a nonirradiated control (p < 0.05). Gluconacetobacter diazotrophicus associates with root hairs and root border cells. Aggregation of bacterial cells was observed in root structures from UV-induced seedlings. Secondary metabolite accumulation was also observed in roots from UV-irradiated seedlings.
Physiological influences in the development and function of the shoot apical meristem of microspore-derived embryos ofBrassica napus‘Topas’
Authors: Ramesar-Fortner Nicole S. , Yeung Edward C. 
Published: June 2006

The effect of auxins and abscisic acid (ABA) on shoot apical meristem development and function was analyzed in microspore-derived embryos of Brassica napus L. ‘Topas’. Embryos were treated with an auxin transport inhibitor, tri-iodobenzoic acid (TIBA) or exogenous indole-3-acetic acid (IAA) at various stages during their development. If embryos were treated at the preglobular or globular stages of embryogenesis, they developed one fused cotyledon indicating a continuation of radial symmetry. However, if treated later in development, embryos were comparable to the control and formed two separate cotyledons. To demonstrate that this was not a pharmacological effect, an auxin antagonist, 2-(p-chlorophenoxy)-2-methylpropionic acid, included with the TIBA treatment produced normal embryos with two separate cotyledons. Histological observations revealed that the shoot apical meristem of the embryos treated with TIBA or IAA at the preglobular and globular stages was altered. Preglobular and globular stage embryos that were treated with TIBA exhibited a dramatic decline in conversion frequency compared with their controls. Embryos that were treated later in development had conversion frequencies comparable to their controls, and their shoot apical meristems also were similar to controls. Application of ABA at the preglobular and globular stages maintained meristem integrity and improved embryo conversion. However, ABA could not reverse the TIBA effect.
Pollinator visitation, pollen limitation, and selection on flower size through female function in contrasting habitats within a population of Campanula persicifolia
Authors: Hansen Vivi-Irèn , Totland Ørjan 
Published: June 2006

We looked at whether flower visitation rates, pollen limitation on seed production, and phenotypic selection on flower size through female function varied across a sharp gradient in light intensity (open meadow vs. forest) within a population of the perennial plant Campanula persicifolia L. (Campanulaceae). Flower visitation rates of putative pollinators were similar in both habitats. Seed number per fruit was strongly pollen limited, with no difference in the magnitude of pollen limitation between the two habitats. This strong pollen limitation set the basis for significant phenotypic selection, through female function, on a trait that probably is important for pollinator attraction: flower size. This was revealed by path analysis and structural equation modelling. The lack of difference in pollen limitation on seed production in the two habitats may be explained by the similarity in flower visitation rates in the two habitats. Moreover, the similarity in pollen limitation in the two habitats probably resulted in a similar magnitude and direction of selection on flower size through female function. Our results suggest that pollen limitation and selection through female function may vary little across space within a popualtion despite large variation in the environmental conditions experienced by plants.
Multi-species fruit and seed removal in a tropical deciduous forest in Mexico
Authors: Briones-Salas Miguel , Sánchez-Cordero Víctor , Sánchez-Rojas Gerardo 
Published: June 2006

We determined patterns of post-dispersal fruit and seed removal for 11 common native plants, as well as sunflower seeds ( Helianthus annuus L.), within a tropical deciduous forest in Jalisco, Mexico. Removal values were high in Delonyx regia (Bojer) Raf. (90%), Crescentia alata Kunth. (87%), H. annus (81%), Pithecellobium dulces (Roxb.) Benth (81%), Albizia occidentalis Brandegee (80%), Coccoloba barbadensis Jacq. (80%), Recchia mexicana DC. (80%), Caesalpinia pulcherrima (L.) Sw. (79%), Enterolobium cyclocarpum (Jacq.) Griseb. (73%), moderate in Guazuma ulmifolia Lam. (42%) and Celtis iguanaeus Sarg. (44%), and low in Amphipterygium adstringens (Schlechtend.) Schiede ex Standl. (17%). Low removal rates (29%) in experimental patches open only to arthropods suggest that arthropods have a minor role in removing fruits and seeds of these species. Removal values were high in experimental patches open to all potential agents (77%) and semipermeable patches open to forest-dwelling rodents (76%), suggesting that the latter group, the most abundant terrestrial mammal in this forest, was an important agent for removing the fruits and seeds of study plants. Removal values were higher in experimental patches located in tropical deciduous forest than in tropical semideciduous forest, as well as higher in high density (patches of 30 fruits or seeds) than in low density (patches of five fruits or seeds) experimental patches for most study plants. Mice appear to selectively remove and hoard fruits and seeds according to their energy and nutritional content and the presence of secondary metabolites, and from from high-density food patches and preferred habitats. Nonindependent effects of species, habitat, and density suggest that a complex interplay of factors determines fruit and seed removal for the plants examined from the Chamela tropical forest.