bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparative study of Endoflare–Hero Shaper and Mtwo NiTi instruments in the preparation of curved root canals
Authors: Veltri M. , Mollo A. , Mantovani L. , Pini P. , Balleri P. , Grandini S. 
Published: August 2005

AbstractAim  To analyse the shaping ability of two new NiTi rotary systems in molar curved canals.Methodology  Thirty molar root canals with curvatures from 24° to 69° were divided into two groups that were balanced in terms of curvature. The canals in one group were shaped using the Mtwo (Sweden & Martina, Padova, Italy) and the canals in the other group using the Endoflare–Hero Shaper (Micro‐Mega, Besançon, France) in a modified sequence. Pre‐ and post‐instrumentation X‐rays were taken using a radiographic platform, with a contrast medium being used to enhance canal opacity. The dentine removed at five positions along the canals, the symmetry of canal shaping and the presence of aberrations were analysed through computer‐aided measurements. The instrument failures, the working time and the changes in working length were also recorded. The Mann–Whitney U‐test was used for statistical analyses.Results  Both systems produced uniform dentine removal and symmetrical canal shapes; there was no significant difference between the systems (P > 0.05). In the apical region, preparations were centred in the canal. A mean loss of working length of 0.55 mm for Mtwo and 0.58 mm for Endoflare–Hero Shaper was detected, with no significant differences between the instruments (P > 0.05). No aberrations were seen and no instruments separated. The mean working time was 124.4 s for the Mtwo system and 141.3 s for the Endoflare–Hero Shaper but this difference was not statistically significant (P > 0.05).Conclusion  The systems tested in this study were effective in shaping curved canals in extracted teeth.
Influence of different types of automated devices on the shaping ability of rotary nickel‐titanium FlexMaster instruments
Authors: Schäfer E. , Erler M. , Dammaschke T. 
Published: August 2005

AbstractAim  To compare the shaping ability of rotary FlexMaster nickel‐titanium instruments in simulated curved canals and in curved canals of extracted teeth when set into permanent rotation with three different torque‐limited automated devices.Methodology  Root canal instrumentation was performed with three different torque‐limited automated devices (ENDOadvance, SIRONiTi and Endo IT motor) by FlexMaster nickel‐titanium instruments up to size 35. Simulated canals: 28° and 35° curved canals in resin blocks (n = 20 canals in each group) were prepared. Pre‐ and post‐instrumentation images were recorded and assessment of canal shape was completed with a computer image analysis program. Extracted teeth: A total of 60 curved root canals were divided into three groups, which were balanced with respect to the angle and the radius of canal curvature. Straightening of the canal curvatures was determined with a computer image analysis program. Incidence of canal aberrations, preparation time, changes of working length and instrument failures were recorded both in simulated and real canals.Results  In simulated and real canals, instrumentation with Endo IT was significantly faster than with SIRONiTi (P < 0.05). With respect to canal aberrations in simulated canals, there were no significant differences between the devices (P > 0.05), even though more aberrations were created with ENDOadvance and SIRONiTi. In real canals, the Endo IT motor resulted in significantly less straightening during instrumentation (P < 0.05) than SIRONiTi. A total of three instruments separated (one file in each group) during the enlargement of 35° curved simulated canals. All systems maintained working distance well.Conclusions  All systems respected original root canal curvature well and were safe, indicating that torque‐limited rotation handpieces are suitable for preparing curved root canals.
A laboratory comparison of three imaging systems for image quality and radiation exposure characteristics
Authors: Bhaskaran V. , Qualtrough A. J. E. , Rushton V. E. , Worthington H. V. , Horner K. 
Published: August 2005

AbstractAim  To measure and compare the relationships between image quality and X‐ray exposure for three types of intraoral imaging system (conventional film, phosphor plate system and CCD‐based system).Methodology  Kodak ‘Insight’ F‐speed film, Digora FMX (phosphor plate system) and Visualix USB (CCD system) were used to produce series of radiographic images of two tooth‐bearing jaw specimens (maxillary molar and mandibular molar regions) at a range of X‐ray exposures from 10 ms to 2000 ms (all at 6 mA and 60 kV). Digital images were viewed from a computer monitor and films viewed on a conventional light box. Five observers scored each image using a five‐point subjective image quality scale (0–4).Results  Optimum image quality (4) was seen for conventional film. Neither digital system achieved this score at any exposure, achieving in both cases a maximum mean score of 3.1 (adequate visualization). The two digital systems, however, provided adequate visualization at substantially lower exposure times. Dose reduction over conventional film for maximum quality images with Visualix USB was 20%, but for Digora FMX it was 70%. All three systems gave acceptable (quality score of two or higher) images over a broad range of exposures.Conclusions  In terms of subjective image quality, F‐speed film performed better than the two digital systems, but this must be weighed against the ability of the two digital systems to give adequate image quality at lower radiation doses.
Communities of nirS‐type denitrifiers in the water column of the oxygen minimum zone in the eastern South Pacific
Authors: Castro‐González Maribeb , Braker Gesche , Farías Laura , Ulloa Osvaldo 
Published: August 2005

SummaryThe major sites of water column denitrification in the ocean are oxygen minimum zones (OMZ), such as one in the eastern South Pacific (ESP). To understand the structure of denitrifying communities in the OMZ off Chile, denitrifier communities at two sites in the Chilean OMZ (Antofagasta and Iquique) and at different water depths were explored by terminal restriction fragment length polymorphism analysis and cloning of polymerase chain reaction (PCR)‐amplified nirS genes. NirS is a functional marker gene for denitrification encoding cytochrome cd1‐containing nitrite reductase, which catalyses the reduction of nitrite to nitric oxide, the key step in denitrification. Major differences were found between communities from the two geographic locations. Shifts in community structure occurred along a biogeochemical gradient at Antofagasta. Canonical correspondence analysis indicated that O2, NO3–, NO2– and depth were important environmental factors governing these communities along the biogeochemical gradient in the water column. Phylogenetic analysis grouped the majority of clones from the ESP in distinct clusters of genes from presumably novel and yet uncultivated denitrifers. These nirS clusters were distantly related to those found in the water column of the Arabian Sea but the phylogenetic distance was even higher compared with environmental sequences from marine sediments or any other habitat. This finding suggests similar environmental conditions trigger the development of denitrifiers with related nirS genotypes despite large geographic distances.
In situ substrate conversion and assimilation by nitrifying bacteria in a model biofilm
Authors: Gieseke Armin , Nielsen Jeppe Lund , Amann Rudolf , Nielsen Per Halkjær , De Beer Dirk 
Published: August 2005

SummaryLocal nitrification and carbon assimilation activities were studied in situ in a model biofilm to investigate carbon yields and contribution of distinct populations to these activities. Immobilized microcolonies (related to Nitrosomonas europaea/eutropha, Nitrosomonas oligotropha, Nitrospira sp., and to other Bacteria) were incubated with [14C]‐bicarbonate under different experimental conditions. Nitrifying activity was measured concomitantly with microsensors (oxygen, ammonium, nitrite, nitrate). Biofilm thin sections were subjected to fluorescence in situ hybridization (FISH), microautoradiography (MAR), and local quantification of [14C]‐bicarbonate uptake (beta microimaging). Nitrifying activity and tracer assimilation were restricted to a surface layer of different thickness in the various experiments (substrate or oxygen limitation). Excess oxygen uptake under all conditions revealed heterotrophic activity fuelled by decay or excretion products during active nitrification. Depth limits and intensity of tracer incorporation profiles were in agreement with ammonia‐oxidation activity (measured with microsensors), and distribution of incorporated tracer (detected with MAR). Microautoradiography revealed a sharp individual response of distinct populations in terms of in‐/activity depending on the (local) environmental conditions within the biofilm. Net in situ carbon yields on N, expressed as e– equivalent ratios, varied between 0.005 and 0.018, and, thus, were in the lower range of data reported for pure cultures of nitrifiers.
Isolation and characterization of Dehalococcoides sp. strain FL2, a trichloroethene (TCE)‐ and 1,2‐dichloroethene‐respiring anaerobe
Authors: He Jianzhong , Sung Youlboong , Krajmalnik‐Brown Rosa , Ritalahti Kirsti M. , Löffler Frank E. 
Published: August 2005

SummaryA strictly anaerobic bacterium was isolated from tetrachloroethene (PCE)‐to‐ethene dechlorinating microcosms established with river sediment without prior exposure to chlorinated solvents. The isolation procedure included the addition of 2‐bromoethanesulfonate to select against methanogenic archaea, > 50 consecutive 1–2% (v/v) transfers to reduced mineral salts medium amended with trichloroethene (TCE), acetate, and hydrogen, the addition of ampicillin, and the dilution‐to‐extinction principle. Culture‐dependent and 16S rRNA gene‐targeted approaches suggested culture purity. Microscopic examination revealed a homogeneous culture of an organism with a distinct, disc‐shaped morphology. The isolate shared > 99% 16S rRNA gene sequence similarity with members of the Pinellas group of the Dehalococcoides cluster, and was designated Dehalococcoides sp. strain FL2. Strain FL2 could be propagated with TCE, cis‐1,2‐dichloroethene (cis‐DCE), or trans‐DCE as the electron acceptors, acetate as the carbon source, and hydrogen as the electron donor in defined, completely synthetic medium. No other growth‐supporting redox couples were identified. Trichloroethene, cis‐DCE and trans‐DCE were dechlorinated at rates of 27.5, 30.4 and 18.8 µmol l−1 day−1 respectively. Quantitative real‐time polymerase chain reaction (PCR) with a fluorescently labelled linear hybridization probe confirmed growth with these electron acceptors, and suggested that strain FL2 captures energy from both the TCE‐to‐cis‐DCE and 1,2‐DCE‐to‐VC dechlorination steps. Tetrachloroethene and vinyl chloride (VC) were slowly and cometabolically dechlorinated in the presence of a growth‐supporting chloroethene, but ethene formation was incomplete, even after prolonged incubation. At room temperature, strain FL2 grew with a doubling time of 2.4 days, and yielded 166.1 ± 10.2 mg of protein per mole of chloride released. In the presence of excess electron acceptor, strain FL2 consumed hydrogen to a concentration of 0.061 ± 0.016 nM. Dechlorination ceased following the addition of 0.5 mM sulfite, whereas sulfate (10 mM) and nitrate (5 mM) had no inhibitory effects.
Gene expression analysis of the mechanism of inhibition of Desulfovibrio vulgaris Hildenborough by nitrate‐reducing, sulfide‐oxidizing bacteria
Authors: Haveman Shelley A. , Greene E. Anne , Voordouw Gerrit 
Published: August 2005

SummarySulfate‐reducing bacteria (SRB) are inhibited by nitrate‐reducing, sulfide‐oxidizing bacteria (NR‐SOB) in the presence of nitrate. This inhibition has been attributed either to an increase in redox potential or to production of nitrite by the NR‐SOB. Nitrite specifically inhibits the final step in the sulfate reduction pathway. When the NR‐SOB Thiomicrospira sp. strain CVO was added to mid‐log phase cultures of the SRB Desulfovibrio vulgaris Hildenborough in the presence of nitrate, sulfate reduction was inhibited. Strain CVO reduced nitrate and oxidized sulfide, with transient production of nitrite. Sulfate reduction by D. vulgaris resumed once nitrite was depleted. A DNA macroarray with open reading frames encoding enzymes involved in energy metabolism of D. vulgaris was used to study the effects of NR‐SOB on gene expression. Shortly following addition of strain CVO, D. vulgaris genes for cytochrome c nitrite reductase and hybrid cluster proteins Hcp1 and Hcp2 were upregulated. Genes for sulfate reduction enzymes, except those for dissimilatory sulfite reductase, were downregulated. Genes for the membrane‐bound electron transferring complexes QmoABC and DsrMKJOP were downregulated and unaffected, respectively, whereas direct addition of nitrite downregulated both operons. Overall the gene expression response of D. vulgaris upon exposure to strain CVO and nitrate resembled that observed upon direct addition of nitrite, indicating that inhibition of SRB is primarily due to nitrite production by NR‐SOB.
Pathogenicity of vibrios to rainbow trout (Oncorhynchus mykiss, Walbaum) and Artemia nauplii
Authors: Austin Brian , Austin Dawn , Sutherland Rowan , Thompson Fabiano , Swings Jean 
Published: August 2005

SummaryThe taxonomy of marine vibrios has changed rapidly over the last two decades, and a wealth of new species have been identified. Many Vibrio species are pathogenic to fish and crustaceans; however, little is known about the virulence of many of the novel species. The purpose of this study was to determine the ability of various recent isolates of vibrios to cause disease in rainbow trout (Oncorhynchus mykiss, Walbaum) and crustacea, i.e. Artemia nauplii. Of 56 isolates, representing 26 species of Enterovibrio, Photobacterium and Vibrio, obtained from a diversity of healthy and diseased aquatic animal hosts and water samples from many geographical locations, Vibrio brasiliensis, V. coralliilyticus, V. ezurae, V. fortis, V. kanaloaei, V. neptunius, V. rotiferianus and V. tubiashii were pathogenic to rainbow trout and Artemia nauplii with mortalities of up to 100%. The extracellular products of these pathogenic isolates were harmful to the animal models. In contrast, cultures of Enterovibrio norvegicus, E. coralii, Photobacterium rosenbergii, Vibrio campbellii, V. chagasii, V. cyclitrophicus, V. gallicus, V. gigasii, V. hepatarius, V. hispanicus, V. lentus, V. nereis, V. pacini, V. pomeroyi, V. shilonii, V. superstes, V. tasmaniensis and V. xuii demonstrated either non‐ or low virulence in the animal models.
Ferroplasma and relatives, recently discovered cell wall‐lacking archaea making a living in extremely acid, heavy metal‐rich environments
Authors: Golyshina Olga V. , Timmis Kenneth N. 
Published: August 2005

SummaryFor several decades, the bacterium Acidithiobacillus (previously Thiobacillus) has been considered to be the principal acidophilic sulfur‐ and iron‐oxidizing microbe inhabiting acidic environments rich in ores of iron and other heavy metals, responsible for the metal solubilization and leaching from such ores, and has become the paradigm of such microbes. However, during the last few years, new studies of a number of acidic environments, particularly mining waste waters, acidic pools, etc., in diverse geographical locations have revealed the presence of new cell wall‐lacking archaea related to the recently described, acidophilic, ferrous‐iron oxidizing Ferroplasma acidiphilum. These mesophilic and moderately thermophilic microbes, representing the family Ferroplasmaceae, were numerically significant members of the microbial consortia of the habitats studied, are able to mobilize metals from sulfide ores, e.g. pyrite, arsenopyrite and copper‐containing sulfides, and are more acid‐resistant than iron and sulfur oxidizing bacteria exhibiting similar eco‐physiological properties. Ferroplasma cell membranes contain novel caldarchaetidylglycerol tetraether lipids, which have extremely low proton permeabilities, as a result of the bulky isoprenoid core, and which are probably a major contributor to the extreme acid tolerance of these cell wall‐less microbes. Surprisingly, several intracellular enzymes, including an ATP‐dependent DNA ligase have pH optima close to that of the external environment rather than of the cytoplasm. Ferroplasma spp. are probably the major players in the biogeochemical cycling of sulfur and sulfide metals in highly acidic environments, and may have considerable potential for biotechnological applications such as biomining and biocatalysis under extreme conditions.
Use of DNA‐stable isotope probing and functional gene probes to investigate the diversity of methyl chloride‐utilizing bacteria in soil
Authors: Borodina Elena , Cox Michael J. , McDonald Ian R. , Murrell J. Colin 
Published: August 2005

SummaryEnrichment and isolation of methyl chloride‐utilizing bacteria from various terrestrial environments, including woodland and forest soils, resulted in the identification of seven methyl chloride‐utilizing strains belonging to the genus Hyphomicrobium, an Aminobacter strain TW23 and strain WG1, which grouped closely with the genus Mesorhizobium. Methyl chloride enrichment cultures were dominated by Hyphomicrobium species, indicating that these bacteria were most suited to growth under the enrichment and isolation conditions used. However, the application of culture‐independent techniques such as DNA‐stable isotope probing and the use of a functional gene probe targeting cmuA, which encodes the methyltransferase catalysing the first step in bacterial methyl chloride metabolism, indicated a greater diversity of methyl chloride‐utilizing bacteria in the terrestrial environment, compared with the diversity of soil isolates obtained via the enrichment and isolation procedure. It also revealed the presence of as yet uncultured and potentially novel methyl chloride‐degrading bacteria in soil.
16S rDNA phylogeny and distribution of lin genes in novel hexachlorocyclohexane‐degrading Sphingomonas strains
Authors: Böltner Dietmar , Moreno‐Morillas Silvia , Ramos Juan‐Luis 
Published: August 2005

SummaryHexachlorocyclohexane (HCH) is a highly recalcitrant pesticide that persists in soils. Three novel HCH‐degrading strains (DS2, DS2‐2 and DS3‐1) were isolated after enrichment from HCH‐contaminated soil from Germany. These strains efficiently degraded the α‐, γ‐ and δ‐isomers of HCH, while strain DS3‐1 also degraded β‐HCH. Based on 16S rDNA analysis, strain DS3‐1 was closely related to Sphingomonas taejonensis, while strains DS2 and DS2‐2 were closely related to Sphingomonas flava and seven HCH‐degrading strains recently isolated from HCH‐contaminated Spanish soil. Hence, geographic origin of the strains was not reflected in their phylogenetic affiliation. Subsequently, lin genes involved in HCH degradation, virtually identical to those from Sphingomonas paucimobilis strains UT26 from Japan and B90A from India, were identified in strains DS3‐1, DS2, DS2‐2 and five of the strains from Spain. The conserved lin gene sequences and structural organization, as well as the close association with IS6100, suggest a shared lin gene origin and recent horizontal gene transfer among phylogenetically diverged Sphingomonas strains in remote geographic locations. The loss of the ability to degrade γ‐HCH was associated with the deletion of the linA gene, probably due to recombination involving IS6100 elements, of which several copies are located in the lin cluster region.
Chromosomally located gene fusions constructed in Acinetobacter sp. ADP1 for the detection of salicylate
Authors: Huang Wei E. , Wang Hui , Zheng Hongjun , Huang Linfeng , Singer Andrew C. , Thompson Ian , Whiteley Andrew S. 
Published: August 2005

Summary Acinetobacter sp. ADP1 is a common soil‐associated bacterium with high natural competency, allowing it to efficiently integrate foreign DNA fragments into its chromosome. This property was exploited to engineer salicylate‐inducible luxCDABE and green fluorescent protein (GFP) variants of Acinetobacter sp. ADP1. Specifically, Acinetobacter sp. ADPWH_lux displayed the higher sensitivity when comparing the two variants (minimum detection c. 0.5–1 µM salicylate) and a faster turnover of the lux marker gene, making it suitable for whole‐cell luminescence assays of salicylate concentration. In contrast, the longer maturation and turnover times of the GFP protein make the Acinetobacter sp. ADPWH_gfp variant more suited to applications involving whole‐cell imaging of the presence of salicylate. The sensitivity of the luxCDABE variant was demonstrated by assaying salicylate production in naphthalene‐degrading cultures. Assays using ADPWH_lux specifically mapped the kinetics of salicylate production from naphthalene and were similar to that observed by high‐performance liquid chromatography (HPLC) data. However, ADPWH_lux exhibited the higher sensitivity, when compared with HPLC, for detecting salicylate production during the first 24 h of naphthalene metabolism. These data demonstrate that the engineered Acinetobacter variants have significant potential for salicylate detection strategies in laboratory and field studies, especially in scenarios where genetic stability of the construct is required for in situ monitoring.
Japan's Large Scale Retail Store Law: a cause of concern for food exporters?
Authors: Odagiri Tokumi , Riethmuller Paul 
Published: August 2005

AbstractThe Large Scale Retail Store Law has been a feature of the Japanese distribution system in one form or another for almost 40 years. It has been viewed by critics as a form of non‐tariff barrier and an impediment to imports. Others view the Large Scale Retail Store Law as just another part of a distribution system that fits in, and has served Japanese society well. Reforms planned for the distribution system are likely to benefit Japanese agriculture just as much as foreign suppliers to the Japanese market.
Conversion subsidies for organic production: results from Sweden and lessons for the United States
Authors: Lohr Luanne , Salomonsson Lennart 
Published: August 2005

AbstractOrganic conversion subsidies used in Europe are less likely to be politically acceptable in the United States, where organic agriculture development is market‐driven. Persistent barriers to conversion in the United States include limited availability of and access to production and market information, training in management systems and cost of conversion‐related investments. By determining whether these factors affect the requirement of a subsidy to convert, we can suggest whether U.S. policy makers need to provide subsidies to encourage conversion and identify policy variables consistent with market‐based approaches that could stimulate conversion. A utility difference model is used with Swedish data to analyze factors that determine whether a subsidy is required to motivate organic conversion. The results show that farmers requiring subsidies manage larger less‐diversified farms and are more concerned with organic inspection, quality, and adequacy of technical advice. Access to more market outlets and information sources substitutes for payment level in the farmer's utility function, indicating that services rather than subsidies may be used to encourage organic agriculture. To the extent that conditions are similar in the U.S. organic sector, market‐based programs such as cost‐sharing for conversion and market access improvement should stimulate growth of this industry.