bluuebunny/crossref_metadata_2025 huggingface dataset:
Autoregulation of antibiotic biosynthesis by binding of the end product to an atypical response regulator
Authors: Wang Linqi , Tian Xiuyun , Wang Juan , Yang Haihua , Fan Keqiang , Xu Gangming , Yang Keqian , Tan Huarong
Published: May 2009

In bacteria, many “atypical” response regulators (ARRs) lack the conserved residues important for phosphorylation by which typical response regulators switch their output response, suggesting the existence of alternative regulatory mechanisms. However, such mechanisms have not been established. JadR1, an OmpR-type ARR ofStreptomyces venezuelae, appears to activate the transcription of jadomycin B (JdB) biosynthetic genes while repressing its own gene. JadR1 activities were inhibited in cells induced to produce JdB, which was found to bind directly to the N-terminal receiver domain of JadR1, causing JadR1 to dissociate from target promoters. The activity of a NarL-type ARR, RedZ, that regulates production of another antibiotic was likewise modulated by the end product (undecylprodigisines), implying that end-product-mediated control of antibiotic pathway-specific ARRs may be widespread. These results could prove relevant to knowledge-based improvements in yield of commercially important antibiotics.
Unique protein architecture of alanyl-tRNA synthetase for aminoacylation, editing, and dimerization
Authors: Naganuma Masahiro , Sekine Shun-ichi , Fukunaga Ryuya , Yokoyama Shigeyuki
Published: May 2009

Alanyl-tRNA synthetase (AlaRS) specifically recognizes the major identity determinant, the G3:U70 base pair, in the acceptor stem of tRNA
Ala
by both the tRNA-recognition and editing domains. In this study, we solved the crystal structures of 2 halves of
Archaeoglobus fulgidus
AlaRS: AlaRS-ΔC, comprising the aminoacylation, tRNA-recognition, and editing domains, and AlaRS-C, comprising the dimerization domain. The aminoacylation/tRNA-recognition domains contain an insertion incompatible with the class-specific tRNA-binding mode. The editing domain is fixed tightly via hydrophobic interactions to the aminoacylation/tRNA-recognition domains, on the side opposite from that in threonyl-tRNA synthetase. A groove formed between the aminoacylation/tRNA-recognition domains and the editing domain appears to be an alternative tRNA-binding site, which might be used for the aminoacylation and/or editing reactions. Actually, the amino acid residues required for the G3:U70 recognition are mapped in this groove. The dimerization domain consists of helical and globular subdomains. The helical subdomain mediates dimerization by forming a helix–loop–helix zipper. The globular subdomain, which is important for the aminoacylation and editing activities, has a positively-charged face suitable for tRNA binding.
Depinning Dynamics of Two-Dimensional Charged Colloids on a Random Laser-Optical Substrate
Authors: Cao Yi-Gang  , Wang Hong-Ling  , Yang Gang  , Han Hong-Pei
Published: May 2009

Using Langevin simulations, we investigate the depinning dynamics of two-dimensional charged colloids on a random laser-optical substrate. With an increase in the strength of the substrate, we find a transition from crystal to smectic flows above the depinning. A power-law scaling relationship between average velocity and applied driving force could be obtained for both flows, and we find that the scaling exponents are no bigger than 1 for the crystal and are bigger than 1 for the smectic flows.
Cupping for Treating Pain: A Systematic Review
Authors: Kim Jong-In , Lee Myeong Soo , Lee Dong-Hyo , Boddy Kate , Ernst Edzard
Published: May 2009

The objective of this study was to assess the evidence for or against the effectiveness of cupping as a treatment option for pain. Fourteen databases were searched. Randomized clinical trials (RCTs) testing cupping in patients with pain of any origin were considered. Trials using cupping with or without drawing blood were included, while trials comparing cupping with other treatments of unproven efficacy were excluded. Trials with cupping as concomitant treatment together with other treatments of unproven efficacy were excluded. Trials were also excluded if pain was not a central symptom of the condition. The selection of studies, data extraction and validation were performed independently by three reviewers. Seven RCTs met all the inclusion criteria. Two RCTs suggested significant pain reduction for cupping in low back pain compared with usual care (P < .01) and analgesia (P < .001). Another two RCTs also showed positive effects of cupping in cancer pain (P < .05) and trigeminal neuralgia (P < .01) compared with anticancer drugs and analgesics, respectively. Two RCTs reported favorable effects of cupping on pain in brachialgia compared with usual care (P = .03) or heat pad (P < .001). The other RCT failed to show superior effects of cupping on pain in herpes zoster compared with anti‐viral medication (P = .065). Currently there are few RCTs testing the effectiveness of cupping in the management of pain. Most of the existing trials are of poor quality. Therefore, more rigorous studies are required before the effectiveness of cupping for the treatment of pain can be determined.
TheRealpolitikof the Artificial: Strategic Design at Figgjo Fajanse Facing International Free Trade in the 1960s
Authors: Fallan Kjetil
Published: May 2009

The 1960 establishment of the European Free Trade Association (EFTA) represented a watershed to Norwegian consumer goods industry. Since the end of World War II domestic manufacturers had been thriving on a small but lucrative home market characterized by an unparalleled demand, effectively protected from foreign competition by strict import regulations and tariffs barriers. The onset of international free trade would dramatically change this market situation, allowing cheap foreign products access to the Norwegian market while at the same time offering export opportunities to an industry traditionally geared to the domestic market. Operating in an industry where appearance is anything but superficial, the crockery manufacturer Figgjo Fajanse realized that product design would be a crucial tool in the reorganization of its operations when adapting to this ‘brave, new world’ of international free trade. Devising a flexible basis for a rational product differentiation, Figgjo made severe cuts in an oversized product portfolio and developed a small range of new models that could accommodate a wide range of decorative patterns of highly different styles. This strategy required elaborate and creative negotiations on the part of the company's designers, creating a ‘third way’—a moderate modern design carved out in the space demarcated by the industrially rational, the commercially viable, and the aesthetically ethical.
A method for reducing uncertainty in estimates of fish-school frequency response using data from multifrequency and multibeam echosounders
Authors: Berger Laurent , Poncelet Cyrille , Trenkel Verena M.
Published: May 2009

Berger, L., Poncelet, C., and Trenkel, V. M. 2009. A method for reducing uncertainty in estimates of fish-school frequency response using data from multifrequency and multibeam echosounders. – ICES Journal of Marine Science, 66: 1155–1161. Fish schools can be insonified simultaneously with multifrequency echosounders (e.g. Simrad EK60s) and a multibeam echosounder (e.g. Simrad ME70). This paper presents a method for combining these data to improve estimates of the relative frequency response r(f) of fish schools. Values of r(f) are now commonly used to classify echoes in fishery surveys. The data from the roll- and pitch-stabilized, high-resolution ME70 are used to correct beam-width effects in the multifrequency EK60 data. First, knowing the exact position and orientation of the transducers and the position of the vessel, the echoes are placed into a common geographic coordinate system. Then, the EK60 data are rejected if they do not include a significant percentage of the fish school imaged with the multibeam echosounder. Echoes that exceed the overlap threshold are used to estimate the r(f). The proposed method is applied to simulated and actual data for sardine and mackerel schools in the Bay of Biscay to estimate their r(f) values. The results for different overlap thresholds are compared with the results of a different method, one that uses adaptive thresholds on volume-backscattering strength Sv. The proposed method reduces uncertainty in estimates of r(f) for schools with an overlap of greater than 80%, and it outperforms the Sv-thresholding technique.
Variable-number tandem repeat 3690 polymorphism in Indian clinical isolates of Mycobacterium tuberculosis and its influence on transcription
Authors: Akhtar Parvez , Singh Sarman , Bifani Pablo , Kaur Satinder , Srivastava Brahm S. , Srivastava Ranjana
Published: May 2009

Variable-number tandem repeat (VNTRs) occur throughout the chromosome of Mycobacterium tuberculosis. Although these polymorphic VNTRs, also known as mycobacterial interspersed repetitive units (MIRUs), have proved to be useful tools in molecular epidemiology, their biological significance is less well understood. This study investigated the polymorphism of the VNTR 3690 locus located in the intergenic region between rv3304 and rv3303c (encoding the gplD2 and lpdA genes, respectively) and its possible function in the regulation of gene expression. The copy number of VNTR 3690 was found to vary among Indian clinical isolates of M. tuberculosis (one to twelve copies), M. tuberculosis H37Rv TMC102 (four copies), M. tuberculosis H37Ra (two to four copies), Mycobacterium bovis BCG (one copy). The expression of lpdA as measured by quantitative RT-PCR was 12-fold higher in M. tuberculosis H37Rv than in M. bovis BCG. Using a GFP reporter system in which the 5′-flanking region of lpdA was fused to the gfp gene, the effect of VNTRs on gene expression was measured in an M. bovis BCG host background by real-time PCR. Compared with one VNTR repeat, a 12.5-fold upregulation of GFP expression was found with a flanking region containing four VNTR 3690 repeats, indicating that there is a good correlation between VNTR copy number and transcription of lpdA.
Characterization of two plasmid-encoded cefotaximases found in clinical Escherichia coli isolates: CTX-M-65 and a novel enzyme, CTX-M-87
Authors: Yin Jun , Cheng Jun , Sun Zhen , Ye Ying , Gao Yu-Feng , Li Jia-Bin , Zhang Xue-Jun
Published: May 2009

Three clinical strains of Escherichia coli (p168, p517 and p667) were collected in 2006 from three hospitals in Anhui Province (China). PCR and DNA sequencing revealed that E. coli p168 carried a novel extended-spectrum β-lactamase (ESBL), which was designated CTX-M-87. The extended-spectrum β-lactamase which was carried by E. coli p517 and E. coli p667 was previously named CTX-M-65. The deduced amino acid sequence of CTX-M-87, with pI 9.1, differed from that of CTX-M-14 by the substitutions Ala77→Val and Pro167→Leu. Like CTX-M-14, CTX-M-87 had a more potent hydrolytic activity against cefotaxime than against ceftazidime and had high affinity for cefuroxime and cefotaxime. These data show that mutations at position 167 in CTX-M do not always affect catalytic activity and substrate preference.
Genotypic versus phenotypic methods in the detection of Listeria monocytogenes prosthetic joint infection
Authors: Žaloudíková Barbora , Kelbl Martin , Paša Libor , Freiberger Tomáš
Published: May 2009

A rare case of a severe prosthetic joint infection in a 71-year-old immunocompetent woman is presented.Listeria monocytogeneswas identified in two consecutive samples using broad-range PCR and sequencing, whereas cultivation remained negative for the first sample and streptococci of a non-group A streptococci, non-group B streptococci type were detected for the second one. This report demonstrates that the phenotypic approach may lead to misidentification ofL. monocytogenesin a routine clinical setting. Molecular methods of pathogen detection might be useful when a rare and/or unexpected micro-organism is present or the sample is collected during antibiotic treatment.
Quantitative real-time PCR analysis of Mycobacterium leprae DNA and mRNA in human biopsy material from leprosy and reactional cases
Authors: Lini Nirmala , Shankernarayan Nallakandy Panangadan , Dharmalingam Kuppamuthu
Published: May 2009

Mycobacterium leprae, the causative agent of leprosy, is uncultivable in defined media. Development of new diagnostic tools which do not depend on growth of bacteria is needed for the early detection ofM. lepraeand for monitoring the effectiveness of chemotherapy. We used a real-time PCR-based assay to quantify the copy number of bacterial DNA andhsp18mRNA from 47 leprosy patients using paraffin-embedded biopsy samples. The assay used was specific, sensitive and reproducible. The applicability of this approach in monitoring the chemotherapy of leprosy was examined. A reduction in DNA and mRNA during chemotherapy was observed andhsp18mRNA could not be detected in patients who underwent 2 years of multidrug therapy (MDT). However, a considerable amount ofM. lepraeDNA could be detected even after 2 years of MDT. A significant amount ofhsp18mRNA was found in reactional cases as well. This raises important questions regarding the role of bacterial antigens in leprosy reactions and the rationale of omitting antibiotics in the treatment of reactional cases. Results in this study show that real-time PCR could be a better tool for the careful monitoring of bacillary DNA and mRNA in lesions, which will help to improve diagnosis, disease progression and the treatment regimen.
Distribution of the ACME-arcA gene among meticillin-resistant Staphylococcus haemolyticus and identification of a novel ccr allotype in ACME-arcA-positive isolates
Authors: Pi Borui , Yu Meihong , Chen Yagang , Yu Yunsong , Li Lanjuan
Published: May 2009

The aim of this study was to investigate the prevalence and characteristics of ACME (arginine catabolic mobile element)-arcA-positive isolates among meticillin-resistant Staphylococcus haemolyticus (MRSH). ACME-arcA, native arcA and SCCmec elements were detected by PCR. Susceptibilities to 10 antimicrobial agents were compared between ACME-arcA-positive and -negative isolates by chi-square test. PFGE was used to investigate the clonal relatedness of ACME-arcA-positive isolates. The phylogenetic relationships of ACME-arcA and native arcA were analysed using the neighbour-joining methods of mega software. A total of 42 (47.7 %) of 88 isolates distributed in 13 PFGE types were positive for the ACME-arcA gene. There were no significant differences in antimicrobial susceptibility between ACME-arcA-positive and -negative isolates. A novel ccr allotype (ccrAB
SHP) was identified in ACME-arcA-positive isolates. Among 42 ACME-arcA-positive isolates: 8 isolates harboured SCCmec V, 8 isolates harboured class C1 mec complex and ccrAB
SHP; 22 isolates harbouring class C1 mec complex and 4 isolates harbouring class C2 mec complex were negative for all known ccr allotypes. The ACME-arcA-positive isolates were first found in MRSH with high prevalence and clonal diversity, which suggests a mobility of ACME within MRSH. The results from this study revealed that MRSH is likely to be one of the potential reservoirs of ACME for Staphylococcus aureus.
Activation of plasminogen activator inhibitor implicates protease InhA in the acute-phase response to Bacillus anthracis infection
Authors: Chung Myung-Chul , Jorgensen Shelley C. , Popova Taissia G. , Tonry Jessica H. , Bailey Charles L. , Popov Serguei G.
Published: May 2009

Anthrax is a zoonotic disease caused byBacillus anthracis. The infection is associated with inflammation and sepsis, but little is known about the acute-phase response during disease and the nature of the bacterial factors causing it. In this study, we examined the levels of the acute-phase proteins (APPs) in comparative experiments using mice challenged with spores and a purifiedB. anthracisprotease InhA as a possible factor mediating the response. A strong increase in the plasma levels of APPs such as haptoglobin and serum amyloid A was observed during infection. Protein and mRNA levels of plasminogen activator inhibitor (PAI)-1 in the liver were also increased concurrently with bacterial dissemination at 72 h post-infection. Similar effects were observed at 6 h post injection with InhA. Induction of hepatic transforming growth factor-β1, a PAI-1 inducer, was also found in the liver of InhA-injected mice. PAI-1 elevation by InhA resulted in an increased level of urokinase-type plasminogen activator complex with PAI-1 and a decreased level of D-dimers indicating inhibition of blood fibrinolysis. These results reveal an acute liver response to anthrax infection and provide a plausible pathophysiological link between the host inflammatory response and the pro-thrombotic haemostatic imbalance in the course of disease through PAI-1 induction in the liver.
Experimental Legionella longbeachae infection in intratracheally inoculated mice
Authors: Gobin Ivana , Susa Milorad , Begic Gabrijela , Hartland Elizabeth L. , Doric Miljenko
Published: May 2009

This study established an experimental model of replicativeLegionella longbeachaeinfection in A/J mice. The animals were infected by intratracheal inoculation of 103–109 c.f.u.L. longbeachaeserogroup 1 (USA clinical isolates D4968, D4969 and D4973). The inocula of 109, 108, 107and 106 c.f.u. of all testedL. longbeachaeserogroup 1 isolates were lethal for A/J mice. Inoculation of 105 c.f.u.L. longbeachaecaused death in 90 % of the animals within 5 days, whilst inoculation of 104 c.f.u. caused sporadic death of mice. All animals that received 103 c.f.u. bacteria developed acute lower respiratory disease, but were able to clearLegionellafrom the lungs within 3 weeks. The kinetics of bacterial growth in the lungs was independent of inoculum size and reached a growth peak about 3 logarithms above the initial inoculum at 72 h after inoculation. The most prominent histological changes in the lungs were observed at 48–72 h after inoculation in the form of a focal, neutrophil-dominant, peribronchiolar infiltration. The inflammatory process did not progress towards the interstitial or alveolar spaces. Immunohistological analyses revealedL. longbeachaeserogroup 1 during the early phase of infection near the bronchiolar epithelia and later co-localized with inflammatory cells. BALB/c and C57BL/6 mice strains were also susceptible to infection with allL. longbeachaeserogroup 1 strains tested and very similar changes were observed in the lungs of infected animals. These results underline the infection potential ofL. longbeachaeserogroup 1, which is associated with high morbidity and lethality in mice.
Clostridium perfringens
β-toxin binding to vascular endothelial cells in a human case of enteritis necroticans
Authors: Miclard Julien , van Baarlen Joop , Wyder Marianne , Grabscheid Benno , Posthaus Horst
Published: May 2009

Clostridium perfringens type C-induced enteritis necroticans is a rare but often fatal disease in humans. A consistent histopathological finding is an acute, deep necrosis of the small intestinal mucosa associated with acute vascular necrosis and massive haemorrhage in the lamina propria and submucosa. Retrospective immunohistochemical investigations of tissues from a diabetic adult who died of enteritis necroticans revealed endothelial localization of C. perfringens
β-toxin in small intestinal lesions. Our results indicate that vascular necrosis might be induced by a direct interaction between C. perfringens
β-toxin and endothelial cells and that targeted disruption of endothelial cells plays a role in the pathogenesis of enteritis necroticans.
Rapid molecular differentiation and genotypic heterogeneity among Candida parapsilosis and Candida orthopsilosis strains isolated from clinical specimens in Kuwait
Authors: Asadzadeh Mohammad , Ahmad Suhail , Al-Sweih Noura , Khan Zia U.
Published: May 2009

Recent molecular studies have led to the recognition of three distinct species within the Candida parapsilosis complex, namely Candida parapsilosis, Candida orthopsilosis and Candida metapsilosis. As currently available yeast identification systems fail to differentiate these species, there is a paucity of information on their occurrence in different geographical regions. This study describes a simple PCR-based protocol for rapid discrimination among C. parapsilosis, C. orthopsilosis and C. metapsilosis strains by using primers derived from unique sequences within the internally transcribed spacer 1 (ITS1)–5.8 rRNA–ITS2 region. Retrospective analysis of 114 C. parapsilosis-complex isolates recovered from clinical specimens in Kuwait identified 109 as C. parapsilosis, five as C. orthopsilosis and none as C. metapsilosis. The results were further validated by PCR-RFLP patterns of the secondary alcohol dehydrogenase gene fragment. DNA sequencing of the ITS region and the D1/D2 regions of the 28S rRNA gene confirmed the species-specific identification of all five C. orthopsilosis strains. The amplicon length of the intergenic spacer between the 28S and 5S rRNA genes (IGS1) was also species-specific, and PCR-RFLP analyses of the IGS1 region identified two distinct genotypes among the five C. orthopsilosis strains, which corresponded with the ITS region sequence data. The three bloodstream C. orthopsilosis strains were confined to a single genotype. Among 81 randomly selected C. parapsilosis strains, two genotypes were detected by IGS1 region analyses, indicating limited genotypic heterogeneity among C. parapsilosis sensu stricto strains. As far as is known, this is the first report on the identification of C. orthopsilosis from a bloodstream infection in the Arabian Gulf region.
Stenotrophomonas maltophilia endogenous endophthalmitis: clinical presentation, sensitivity spectrum and management
Authors: Das T. , Deshmukh H. S. , Mathai A. , Reddy Ashok Kumar
Published: May 2009

Stenotrophomonas maltophiliais gaining importance as a community-acquired pathogen, after becoming firmly established as a nosocomial pathogen. Here we report a case of endogenous endophthalmitis due toS. maltophilia. Antibiotic-susceptibility testing of the isolate was performed by the Kirby–Bauer disc diffusion method. The organism was resistant to aminoglycosides, imipenem, ticarcillin and cotrimoxazole and was sensitive to ceftazidime and chloramphenicol. The patient was successfully treated with a sensitivity-based intravitreal antibiotic regimen.
Long‐term ecological sites: musings on the future, as seen (dimly) from the past
Authors: JANZEN H. H.
Published: May 2009

Long‐term ecological sites are ‘listening places’– places where we press our ears to the earth and strain to hear its pulse. Such sites will be needed especially in coming decades, as ecosystems throughout the world face mounting stresses, mostly from human influences. My aim, in these musings, is to elicit conversation, by way of seven questions, about how best to look after the long‐term sites, so that they remain intact, relevant, and enlightening for our successors, decades hence.
Transcriptome and proteome analysis of ovaries of arrhenotokous and thelytokous Venturia canescens
Authors: Mateo Leach I. , Hesseling A. , Huibers W. H. C. , Witsenboer H. , Beukeboom L. W. , Van De Zande L.
Published: May 2009

Under arrhenotoky, unfertilized haploid eggs develop as males but under thelytoky they develop into diploid females after they have undergone diploidy restoration. In the parasitoid wasp Venturia canescens both reproductive modes occur. Thelytoky is genetically determined but the underlying genetics of diploidy restoration remain unknown. In this study we aim to identify the genes and/or proteins that control thelytoky. cDNA‐amplified fragment length polymorphism (cDNA‐AFLP) analysis of total ovarian RNA and two‐dimensional protein electrophoresis in combination with mass spectrometry revealed putative transcripts and proteins involved in arrhenotokous and thelytokous development. The detected tubulin and actin protein differences are most likely functionally related to the two types of reproduction.
Mechanical response of nickel–titanium instruments with different cross‐sectional designs during shaping of simulated curved canals
Authors: Kim H. C. , Kim H. J. , Lee C. J. , Kim B. M. , Park J. K. , Versluis A.
Published: May 2009

Aim  To evaluate how different cross‐sectional designs affect stress distribution in nickel–titanium (NiTi) instruments during bending, torsion and simulated shaping of a curved canal.

Methodology  Four NiTi rotary instruments with different cross‐sectional geometries were selected: ProFile and HeroShaper systems with a common triangle‐based cross section, Mtwo with an S‐shaped rectangle‐based design and NRT with a modified rectangle‐based design. The geometries of the selected files were scanned in a micro‐CT and three‐dimensional finite‐element models were created for each system. Stiffness characteristics for each file system were determined in a series of bending and torsional conditions. Canal shaping was simulated by inserting models of the rotating file into a 45° curved canal model. Stress distribution in the instruments was recorded during simulated shaping. After the instruments were retracted from the canal, residual stresses and permanent bending of their tips due to plastic deformation were determined.

Results  The greatest bending and torsional stiffness occurred in the NRT file. During simulated shaping, the instruments with triangle‐based cross‐sectional geometry had more even stress distributions along their length and had lower stress concentrations than the instruments with rectangle‐based cross sections. Higher residual stresses and plastic deformations were found in the Mtwo and NRT with rectangle‐based cross‐sectional geometries.

Conclusions  Nickel–titanium instruments with rectangle‐based cross‐sectional designs created higher stress differentials during simulated canal shaping and may encounter higher residual stress and plastic deformation than instruments with triangle‐based cross sections.
The influence of coronal tooth tissue in the diagnosis of apical pathosis
Authors: Rushton V. E. , Qualtrough A. J. E. , Al‐Masserah Y. , Rushton M. N.
Published: May 2009

Aim  To assess the influence of the status of the crown of the tooth on the observers’ periapical radiological assessment.

Methodology  Seven clinical tutors, eight postgraduate students and seven undergraduate students were recruited. Each evaluated 24 periapical radiographs comprising 12 radiographs with teeth restored with small to medium coronal restorations and 12 radiographs displaying teeth which were either heavily restored or exhibited gross caries. Two viewing sessions, separated by several weeks, were undertaken using ideal viewing conditions. In the first viewing teeth were examined in their entirety and in the second the coronal aspects of the teeth were obscured.

Results  An analysis of variance found no significant differences between the groups of observers during the first viewing. When the crowns were masked, undergraduate students had a significantly lower sensitivity (P = 0.008) compared with postgraduates and clinical tutors. Paired t‐tests found a significant increase in the sensitivity of the postgraduate students between the first and second viewing (P = 0.037). Mean sensitivity and specificity for the undergraduates decreased from 0.67 to 0.63 and 0.64 to 0.60 for the first and second viewing, respectively, whilst mean sensitivity for postgraduates and clinical tutors increased from 0.59 to 0.79 and 0.69 to 0.80, respectively. Specificity increased from 0.72 to 0.78 for the postgraduates between viewings, whilst the tutors recorded 0.80 for each viewing.

Conclusion  The status of coronal tooth tissue had a major impact on the diagnostic accuracy of the observers with limited radiological experience supporting the need for earlier radiological training within the undergraduate curriculum.
Evaluation of several protocols for the application of ultrasound during the removal of cast intraradicular posts cemented with zinc phosphate cement
Authors: Garrido A. D. B. , Oliveira A. G. , Osório J. E. V. , Silva‐Sousa Y. T. C. , Sousa‐Neto M. D.
Published: May 2009

Aim  To evaluate several protocols for the application of ultrasound during removal of cast posts with varying core configurations cemented with zinc phosphate.

Methodology  Sixty maxillary canines were distributed into three groups (n = 20): group 1 – core with 5 mm diameter/height and post diameter of 1.3 mm; groups 2 and 3 – core with the same diameter as the post (1.3 mm) and heights of 5 mm and 3 mm, respectively. Posts/cores were cemented using a standard technique with zinc phosphate cement. Each group was divided into two subgroups according to the ultrasonic vibration mode: point vibration – ultrasonic vibration applied to the core surface for 5 s, on each face totalling 25 s; alternate vibration – intermittent application of ultrasonic vibration for 10 s to the labial and lingual surfaces, 10 s to the mesial and distal surfaces and 5 s to the incisal surface, totalling 25 s. The specimens were submitted to the tensile test using an Instron machine (1 mm min−1) and results were analysed by anova and t‐test. The failure type was also analysed.

Results  Statistical analysis showed significant differences between groups relating to the core preparations (P < 0.05). The lowest mean values of traction force were obtained for group 3 (46.1 ± 7.7 N), followed by group 2 (89.0 ± 2.7 N) and group 1 (160.4 ± 7.5 N). Regarding ultrasonic vibration, the lowest mean was observed with alternate vibration (81.1 ± 10.1 N), which was significantly lower than the point vibration (115.9 ± 9.5 N) (P < 0.05). Cohesive failure occurred in all cases.

Conclusion  A reduction in core diameter/height and intermittent ultrasonic application improved the removal of cast posts cemented with zinc phosphate.
Pain associated with root canal treatment
Authors: Segura‐Egea J. J. , Cisneros‐Cabello R. , Llamas‐Carreras J. M. , Velasco‐Ortega E.
Published: May 2009

Aim  To determine the pain experienced by patients during root canal treatment and to correlate with age and gender, pulpal diagnosis, previous periapical status, dental characteristics and length of treatment.

Methodology  One hundred and seventy‐six patients (68 men and 108 women), with ages ranged from 6 to 83 years, were randomly recruited. Patients completed a 10‐cm visual analogue scale (VAS) that ranked the level of pain experienced during root canal treatment.

Results  The mean pain level during root canal treatment was 1.2 ± 0.8 in a VAS between 0 and 10. Fifty‐four per cent of patients did not experience pain. There were no significant differences in relation to gender or age groups. Mandibular teeth had a significantly (P < 0.05) higher percentage incidence of pain in comparison with maxillary teeth. Pain was absent in 63% of anterior teeth compared with 44% in posterior ones (P < 0.01). Interventions shorter than 45 min resulted in a significantly higher percentage of pain absence (P < 0.05). Root canal treatment was significantly (P < 0.05) more painful in teeth with irreversible pulpitis and acute apical periodontitis compared to the group with necrotic pulps and chronic apical periodontitis (P = 0.049).

Conclusions  Root canal treatment in teeth with irreversible pulpitis and acute apical periodontitis was more painful. Age, tooth type and length of the treatment were factors associated with increased risk for pain experienced during the procedure. Knowledge of pain levels endured by patients will allow dentists to decide when to use supplemental local anaesthesia.
Effect of heat treatment on transformation temperatures and bending properties of nickel–titanium endodontic instruments
Authors: Yahata Y. , Yoneyama T. , Hayashi Y. , Ebihara A. , Doi H. , Hanawa T. , Suda H.
Published: May 2009

Aim  To investigate the effect of heat treatment on the bending properties of nickel–titanium endodontic instruments in relation to their transformation behaviour.

Methodology  Nickel–titanium super‐elastic alloy wire (1.00 mm Ø) was processed into a conical shape with a 0.30 mm diameter tip and 0.06 taper. The heat treatment temperature was set at 440 or 500 °C for a period of 10 or 30 min. Nonheat‐treated specimens were used as controls. The phase transformation behaviour was examined using differential scanning calorimetry. A cantilever‐bending test was used to evaluate the bending properties of the specimens. Data were analyed by anova and the Tukey–Kramer test (P = 0.05).

Results  The transformation temperature was higher for each heat treatment condition compared with the control. Two clear thermal peaks were observed for the heat treatment at 440 °C. The specimen heated at 440 °C for 30 min exhibited the highest temperatures for Ms and Af, with subsequently lower temperatures observed for specimens heated at 440 °C for 10 min, 500 °C for 30 min, 500 °C for 10 min, and control specimens. The sample heated at 440 °C for 30 min had the lowest bending load values (P < 0.05), both in the elastic range (0.5 mm deflection) and in the super‐elastic range (2.0 mm deflection). The influence of heat treatment time was less than that of heat treatment temperature.

Conclusions  Change in the transformation behaviour by heat treatment may be effective in increasing the flexibility of nickel–titanium endodontic instruments.
Degree of conversion of dual‐cured resin cement light‐cured through three fibre posts within human root canals: an ex vivo study
Authors: Kim Y. K. , Kim S. K. , Kim K. H. , Kwon T. Y.
Published: May 2009

Aim  To evaluate the degree of conversion of one dual‐cured resin cement light‐cured through three fibre posts within extracted human teeth.

Methodology  Fifteen mandibular premolars were root filled and then divided into three groups. Variolink II was light‐cured through the posts (LP, D.T. Light‐Post; PP, FRC Postec Plus; SP, Snowpost) within the root canal. The degree of conversion was obtained at 1 mm intervals in 9 mm‐deep longitudinally sectioned root canals using an optical microscope connected to an FTIR spectrophotometer (n = 10). The light transmission of each post tested was also examined using UV–Vis spectroscopy. Data were analysed using anova and Tukey’s test (α = 0.05).

Results  The LP and PP posts revealed a light transmission of 10.2% and 7.7%, respectively, whereas the SP post exhibited a significantly lower value of 0.5%. The degree of conversion mean value ranged from 32.78% to 69.73% depending on the depth and type of post. For all the groups, there were significant decreases in the degree of conversion values for the middle region when compared with those for the cervical region (P < 0.05). Except at a depth of 1 mm, the SP group consistently exhibited significantly lower degree of conversion values than the other groups (P < 0.05). The linear regression analysis revealed a strong correlation between the light transmission of the posts and the overall degree of conversion value for each group (R2 = 0.9888).

Conclusions  The decrease in the degree of conversion for Variolink II relative to the depth was dependent on the light transmission capacity of the posts tested.
Expression of insulin‐like growth factor‐1 and proliferating cell nuclear antigen in human pulp cells of teeth with complete and incomplete root development
Authors: Caviedes‐Bucheli J. , Canales‐Sánchez P. , Castrillón‐Sarria N. , Jovel‐Garcia J. , Alvarez‐Vásquez J. , Rivero C. , Azuero‐Holguín M. M. , Diaz E. , Munoz H. R.
Published: May 2009

Aim  To quantify the expression of insulin‐like growth factor‐1 (IGF‐1) and proliferating cell nuclear antigen (PCNA) in human pulp cells of teeth with complete or incomplete root development, to support the specific role of IGF‐1 in cell proliferation during tooth development and pulp reparative processes.

Methodology  Twenty six pulp samples were obtained from freshly extracted human third molars, equally divided in two groups according to root development stage (complete or incomplete root development). All samples were processed and immunostained to determine the expression of IGF‐1 and PCNA in pulp cells. Sections were observed with a light microscope at 80× and morphometric analyses were performed to calculate the area of PCNA and IGF‐1 immunostaining using digital image software. Mann–Whitney’s test was used to determine statistically significant differences between groups (P < 0.05) for each peptide and the co‐expression of both.

Results  Expression of IGF‐1 and PCNA was observed in all human pulp samples with a statistically significant higher expression in cells of pulps having complete root development (P = 0.0009).

Conclusion  Insulin‐like growth factor‐1 and PCNA are expressed in human pulp cells, with a significant greater expression in pulp cells of teeth having complete root development.
Attitudes of final year dental students to the use of rubber dam
Authors: Mala S. , Lynch C. D. , Burke F. M. , Dummer P. M. H.
Published: May 2009

Aim  To investigate the attitudes of final year dental students in Wales and Ireland to the use of rubber dam.

Methods  A pre‐piloted questionnaire was distributed to final year dental students in Cardiff and Cork Dental Schools in January 2008. Information sought included attitudes to, and the current and anticipated use of, rubber dam for a variety of operative and endodontic treatments.

Results  Of 93 questionnaires distributed, 87 were completed and returned (response rate = 94%; Cardiff: 89%, n = 51; Cork: 100%, n = 36). Rubber dam was routinely used by 98% of respondents (n = 85) on adult patients, but only 32% of respondents (n = 28) had used rubber dam on child patients (P < 0.05). Rubber dam was never used by 75% of respondents (n = 65) when placing posterior amalgam restorations, and by 21% of respondents (n = 18) when placing anterior composite restorations. Rubber dam was used by 98% of the respondents (n = 85) when performing root canal treatments. Sixty‐two per cent of respondents (n = 54) believed their use of rubber dam would decrease once leaving the dental school.

Conclusion  Whilst dental students believe that rubber dam is relevant to clinical dentistry, there are negative perceptions associated with its use amongst dental students. More than half of those questioned predicted their use of rubber dam would decrease once in independent practice. Greater emphasis should be placed on the advantages of using rubber dam in clinical dentistry whilst at dental school.
Fracture resistance of roots using different canal filling systems
Authors: Karapinar Kazandag M. , Sunay H. , Tanalp J. , Bayirli G.
Published: May 2009

Aim  To evaluate the fracture resistance of teeth filled with various canal filling materials.

Methodology  The crowns of 100 single‐rooted teeth were removed leaving 12 mm of the roots. The canals were shaped using Endo‐Sequence files. Following instrumentation, 80 teeth were divided into four groups. The remaining 20 teeth were divided into two groups. The teeth in each group were filled as follows: Group 1: AH‐Plus + Gutta‐percha (Cold lateral compaction), Group 2: Resilon + Epiphany (Cold lateral compaction), Group 3: ActiV GP cone + ActiV GP sealer, Group 4: ActiV GP sealer + Gutta‐percha (Cold lateral compaction), Group 5: No instrumentation or filling, Group 6: Instrumentation but no filling. After the sealers had set, the roots were embedded in acrylic moulds and subjected to a compressive loading at a rate of 1 mm min−1. The load at which fracture occurred was recorded and statistically analysed using Kruskal–Wallis one‐way analysis of variance and Z‐tests.

Results  The fracture values of the experimental teeth were significantly higher than those of the instrumented but unfilled group (P < 0.05). Teeth in the AH‐Plus + lateral compaction group had higher fracture resistance compared with the ActiV GP sealer + Gutta‐percha group (P < 0.05).

Conclusions  Systems aiming to obtain a monoblock system were not superior to the conventional AH‐Plus + Gutta‐percha technique in terms of fracture resistance. The fracture resistance of roots using ActiV GP + lateral compaction Gutta‐percha was significantly reduced compared with the AH‐Plus + Gutta‐percha group.
Effect of filling technique and root canal area on the percentage of gutta‐percha in laterally compacted root fillings
Authors: Souza E. M. , Wu M‐K. , Van Der Sluis L. W. , Leonardo R. T. , Bonetti‐Filho I. , Wesselink P. R.
Published: May 2009

Aim  To determine the influence of filling technique and root canal area on the percentage of gutta‐percha (PGP) in laterally compacted root fillings.

Methodology  Sixty extracted canine teeth were accessed and the root canals instrumented to the same size. They were then divided in three groups and filled with laterally compacted gutta‐percha cones and AH Plus using different techniques. A variation of cold lateral compaction using a sequence of spreaders prior to accessory cone placement was compared to two commonly‐used techniques. Twenty additional canines with prepared root canals were used as negative controls in which gutta‐percha was introduced into the canals but no compaction applied. The roots were sectioned horizontally at 3 and 6 mm from the apex and micro‐photographs taken. Using software, the area of the canals and gutta‐percha at each level were measured and PGP calculated. A Multivariate analysis was used to determine the variables influencing PGP. A linear regression test was used to verify the variation in PGP explained by canal area.

Results  At each level the largest canal was two to three times wider than the smallest. Canal area significantly influenced the PGP at both levels (P < 0.05), however, the variation in PGP was only partially explained by canal area (r2 = 0.154, 6 mm; r2 = 0.119, 3 mm). The PGP at the 3 mm level was lower than at 6 mm (P = 0.003). The spreader‐sequence technique achieved a higher PGP than the other two techniques (P = 0.00002). The control group had the lowest area of GP.

Conclusions  Variations in root canal filling technique and canal area influenced the percentage of gutta‐percha of laterally compacted root fillings. The percentage of gutta‐percha was lower at the 3 mm level compared to the 6 mm level.
From paper‐and‐pen annotations to artefact‐based mobile learning
Authors: Hoff C. , Wehling U. , Rothkugel S.
Published: May 2009

Making annotations on books and learning materials is part of students' everyday life. Although there are many computer‐based annotation systems, many people prefer to print digital documents and make annotations on physical paper. We introduce a classification scheme for computer‐based annotation systems and provide an overview of different systems using this scheme. During our investigations, we identified several shortcomings in existing annotation systems: limitation to single document formats, no capturing of relations to reflect lateral reading, loss of context information an annotation was created in and limited sharing capabilities among collaborative users. To overcome these shortcomings, we introduce the concepts of Anchor Points, Artefacts and Spaces. Anchor Points define locations in arbitrary documents. Artefacts capture annotations on multiple Anchor Points in several documents, allowing students to map their current working context that typically contains several open documents and a relationship between them. Spaces are repositories for the learning materials and annotations that are automatically replicated among collaborative mobile users.
Host rock dolomitization and secondary porosity development in the Upper Devonian Cairn Formation of the Fairholme carbonate complex (South‐west Alberta, Canadian Rockies): diagenesis and geochemical modelling
Authors: VANDEGINSTE VEERLE , SWENNEN RUDY , REED MARK H. , ELLAM ROB M. , OSADETZ KIRK , ROURE FRANÇOIS
Published: May 2009

The Upper Devonian carbonate reefs in West‐central Alberta are important petroleum reservoirs that are well‐known for their extensive secondary porosity. An outcrop analogue study indicates that an early matrix‐selective dolomitization event occurred which is characterized by a major Late Devonian sea water component with increased salinity because of evaporation. It is interpreted that the matrix (replacive) dolomite formed during the Famennian as the result of a combination of both seepage and latent reflux dolomitization, although an additional type or overprinting of later intermediate burial dolomitization cannot be excluded. Formation of the moulds is attributed mainly to the dissolution of undolomitized fossil cores, most typically stromatoporoids. Geochemical modelling indicates that carboxylic acid fluids have the highest potential for dissolving residual calcite in this case. Geochemical models consistent with this analysis and interpretations can reproduce the secondary porosity and suggest a viable dolomitization process for the localities studied.
Links between bulk sediment particle size and magnetic grain‐size: general observations and implications for Chinese loess studies
Authors: OLDFIELD FRANK , HAO QINGZHEN , BLOEMENDAL JAN , GIBBS‐EGGAR ZOË , PATIL SHIVA , GUO ZHENGTANG
Published: May 2009

Using a combination of particle size analysis, magnetic measurements, scanning electron microscopy and transmission electron microscopy imaging, this study shows that in a wide range of depositional environments, there is a strong link between particle size classes and magnetic response, especially below the upper limit of stable single domain magnetic behaviour. Ferrimagnetic grain assemblages dominated by stable single domain magnetosomes regularly have peak susceptibility and remanence values in coarser grades than do those containing finer‐grained, viscous and superparamagnetic secondary magnetic minerals formed during pedogenesis. This effect is despite the fact that there is a one to two orders of magnitude size difference between the particle size boundaries (at 1 or 2 μm) and key domain state transitions (mostly below 0·05 μm). The implications of these results are explored using samples spanning 22 Myr of loess accumulation on the Chinese Loess Plateau. The results from the loess sections, complemented by data from low‐temperature magnetic experiments, show that there are subtle distinctions in mean ferrimagnetic grain‐size between the Pleistocene and Miocene parts of the record, thus allowing more refined rock magnetic interpretations of the fine‐grained ferrimagnetic mineral assemblages arising from the effects of weathering, pedogenesis and possibly diagenesis in the sections studied.
Earliest symptoms discriminating juvenile‐onset bipolar illness from ADHD
Authors: Luckenbaugh David A , Findling Robert L , Leverich Gabriele S , Pizzarello Scott M , Post Robert M
Published: May 2009

Objectives:  Controversy surrounds the diagnosis and earliest symptoms of childhood‐onset bipolar illness, emphasizing the importance of prospective longitudinal studies. To acquire a preliminary, more immediate view of symptom evolution, we examined the course of individual symptoms over the first 10 years of life in juvenile‐onset bipolar illness (JO‐BP) compared with attention‐deficit hyperactivity disorder (ADHD).

Methods:  Parents of formally diagnosed children retrospectively rated 37 symptoms in each year of the child’s life based on the degree of dysfunction in their child’s usual family, social, or educational roles. A subset of children with onset of bipolar disorder prior to age 9 (JO‐BP) compared with those with ADHD was the focus of this analysis.

Results:  Brief and extended periods of mood elevation and decreased sleep were strong early differentiators of JO‐BP and ADHD children. Depressive and somatic symptoms were later differentiators. Irritability and poor frustration tolerance differentiated the two groups only in their greater incidence and severity in JO‐BP compared with a moderate occurrence in ADHD. In contrast, hyperactivity, impulsivity, and decreased attention showed highly similar trajectories in the two groups.

Conclusions:  Elevated mood and decreased sleep discriminated JO‐BP and ADHD as early as age 3, while classic ADHD symptoms were parallel in the groups. These retrospective results provide preliminary insights into symptom differences and their temporal evolution between bipolar disorder and ADHD in the first 10 years of life.