bluuebunny/crossref_metadata_2025_split huggingface dataset:
First‐arrival traveltime tomography using second generation wavelets
Authors: Delost Matthieu , Virieux Jean , Operto Stéphane 
Published: June 2008

ABSTRACTWavelet decomposition of the slowness model allows a multiscale description of the seismic first‐arrival time tomography. We propose the introduction of the so‐called second generation wavelets that could be used for any mesh structure and do not require a number of samples, such as the power of two in each direction for fast wavelet transform. A linearized procedure for inverting delayed travel‐times considering either slowness coefficients or wavelet coefficients has been set up with an efficient ray tracing at each iteration of the inversion procedure. Wavelet decomposition over constant patches (Haar wavelet) or over linear patches (Battle‐Lemarie wavelet) of coefficients at different scales are inverted as unknowns of the tomographic linearized system. Reconstruction of these coefficients depends dynamically on the local resolution when considering dense ray coverage. On simple synthetic examples, it has been found necessary to perform a local resolution analysis for specifying wavelet coefficients to be inverted. This resolution analysis could be performed for an initial smooth reconstructed medium and by designing a bit mask operator it allows fine scales to be inverted in specific areas of the model where the resolution is high while not being inverted in other areas where the resolution is poor: the wavelet decomposition will ease the multiscale reconstruction. A few synthetic examples, such as crosshole tomography or surface‐surface tomography illustrate the multiscale feature of wavelet tomography. The second generation wavelet approach seems to be a flexible and rather promising tool for controlling the resolution variation of seismic first‐arrival tomography.
Three‐dimensional kinematic depth migration of converted waves: application to the 2002 Molise aftershock sequence (southern Italy)
Authors: Latorre Diana , De Gori Pasquale , Chiarabba Claudio , Amato Alessandro , Virieux Jean , Monfret Tony 
Published: June 2008

ABSTRACTMigration techniques, currently used in seismic exploration, are still scarcely applied in earthquake seismology due to the poor source knowledge and sparse, irregular acquisition geometries. At the crustal scale, classical seismological studies often perform inversions based on the arrival time of primary phases (P‐ and S‐waves) but seldom exploit other information included in seismic records. Here we show how migration techniques can be adapted to earthquake seismology for converted wave analysis. As an example, we used data recorded by a dense local seismic network during the 2002 Molise aftershock sequence. In October and November 2002, two moderate magnitude earthquakes struck the Molise region (southern Italy), followed by an aftershock sequence lasting for about one month. Local earthquake tomography has provided earthquake hypocenter locations and three‐dimensional models of P and S velocity fields. Strong secondary signals have been detected between first‐arrivals of P‐ and S‐waves and identified as SP transmitted waves. In order to analyse these waves, we apply a prestack depth migration scheme based on the Kirchhoff summation technique. Since source parameters are unknown, seismograms are equalized and only kinematic aspects of the migration process are considered. Converted wave traveltimes are calculated in the three‐dimensional (3D) tomographic models using a finite‐difference eikonal solver and back ray tracing. In the migrated images, the area of dominant energy conversion corresponds to a strong seismic horizon that we interpreted as the top of the Apulia Carbonate Platform and whose geometry and position at depth is consistent with current structural models from existing commercial seismic profiles, gravimetric and well data.
Histological evaluation of direct pulp capping with a self‐etching adhesive and calcium hydroxide on human pulp tissue
Authors: Lu Y. , Liu T. , Li H. , Pi G. 
Published: June 2008

AbstractAim  To evaluate human pulp tissue response following direct pulp capping with a self‐etching adhesive: Clearfil SE BOND (SB).Methodology  Forty‐five sound teeth from 20 subjects were used. Forty‐one teeth had their pulp mechanically exposed at the base of a Class 1 cavity preparation and were divided into two groups: group 1, teeth were capped with SB (n = 21), and group 2, with calcium hydroxide cement (CH) (n = 20). Four teeth were maintained intact as an untreated control group. After 7, 30 and 90 days, respectively, 15 teeth were extracted and processed for light microscopic examination. Pulp healing and bacterial microleakage were assessed by haematoxylin and eosin, Masson trichrome and Brown and Brenn stain techniques. The data were analysed statistically by using the Mann–Whitney U test.Results  After the 7‐day observation period, the inflammatory reaction in the SB group was slight and significantly less severe than that of the CH group (P < 0.05). After the 30‐ and 90‐day observation periods, the inflammatory reaction was slight in both groups, but specimens with dentine bridge formation in the SB group were significantly less common than those in the CH group (P < 0.05).Conclusions  Clearfil SB had good biocompatibility with human pulp tissue, but its ability to induce reparative dentine was significantly lower than that of calcium hydroxide.
Do bioactive glasses convey a disinfecting mechanism beyond a mere increase in pH?
Authors: Gubler M. , Brunner T. J. , Zehnder M. , Waltimo T. , Sener B. , Stark W. J. 
Published: June 2008

AbstractAim  To test whether bioactive glasses kill microbiota via mineralization or the release of ions other than sodium.Methodology  Flame‐spray synthesis was applied to produce nanometric glasses of different sodium content and constant Ca/P ratio: 28S5, 45S5 and 77S. Calcium hydroxide and nanometric tricalcium phosphate (TCP) were used as controls. Apatite induction was monitored by Raman spectroscopy. Bovine dentine disks with adherent Enterococcus faecalis cells were exposed to test and control suspensions or buffered solutions for 1 h, 1 day and 1 week. Colony‐forming units were counted and disks were inspected using scanning electron microscopy. Suspension supernatants and solutions were analysed for their pH, osmolarity, calcium and silicon content.Results  Sodium containing glasses induced pH levels above 12, compared with less than pH 9 with sodium‐free 77S. Calcium hydroxide, 45S5 and 28S5 killed all bacteria after 1 day and lysed them after 1 week. TCP caused the highest apatite induction and substantial calcification on bacteria adhering to dentine, but did not reduce viable counts. 77S achieved disinfection after 1 week without visible apatite formation, whilst the buffer solution at pH 9 caused only minimal reduction in counts.Conclusion  Bioactive glasses have a directly and an indirectly pH‐related antibacterial effect. The effect not directly linked to pH is because of ion release rather than mineralization.
Technical quality of root fillings performed by dental students at the dental teaching centre in Reims, France
Authors: Moussa‐Badran S. , Roy B. , Bessart du Parc A. S. , Bruyant M. , Lefevre B. , Maurin J. C. 
Published: June 2008

AbstractAim  To evaluate the technical quality of root fillings performed by undergraduate students at a dental teaching centre in France.Methodology  A random sample of 419 records of patients who received dental treatment at the dental service of the teaching Hospital, in Reims, France between 2005 and 2006 was investigated. Evaluation of root filled was based on radiographical criteria defined by the French National Health Service. The length of root fillings, the radiodensity and the presence of voids in the root filling or between root filling and root canal walls were recorded and scored. Chi‐square analysis was used to determine statistically significant differences between the technical quality of root fillings and tooth type.Results  Of the 304 teeth included in the study, 69% had an adequate length of root filling and 42.7% had a dense root filling without voids; only 30.3% of teeth fulfilled these criteria at the same time. The relationship between the technical quality of root fillings and tooth type was statistically significant (P < 0.001), the highest percentage of adequate root fillings occurred in single‐rooted teeth (36.1%). The highest percentage of inadequate root fillings according to the criteria of root filling length and lateral adaptation was found in molar teeth (71.9%).Conclusion  Overall, the technical quality of root fillings performed by undergraduate students was poor.
Determination of pulp vitality in vivo with pulse oximetry
Authors: Calil E. , Caldeira C. L. , Gavini G. , Lemos E. M. 
Published: June 2008

AbstractAim  To evaluate the use of pulse oximetry as a test for pulp vitality, by comparing in the same patient, the levels of oxygen saturation of the index finger and of the maxillary central incisor and canine teeth without clinically detectable pulp inflammation.Methodology  Seventeen male and female patients aged between 26 and 38 years participated and a total of 32 maxillary central incisor and 32 canine teeth were analysed. Selection criteria required the teeth to have healthy crowns, or with restorations no more than 2 mm in diameter and no clinical and radiographical signs or symptoms of pulp or periapical inflammatory changes. The negative control group consisted of 10 root filled teeth. Measurements were first taken from the index finger of patients. Their teeth were then subjected to a thermal test with refrigerant gas and then to a vitality test with pulse oximetry. Data were analysed by Pearson’s and paired t‐tests.Results  There were no significant statistical correlations between blood oxygen levels in the index finger and in the teeth of the patient (P > 0.05). There was a statistically significant difference in the oxygen levels between the two tooth groups studied and the index finger (P ≤ 0.002). Mean oxygen values in the index finger of patients were 95% (SD = 1.6), oxygen values in the maxillary central incisor were 91.29% (SD = 2.61) and mean oxygen values in maxillary canine were 90.69% (SD = 2.71).Conclusion  The method determined consistently the level of blood oxygen saturation of the pulp in maxillary central incisor and canine teeth and can therefore be used for pulp vitality testing. Further studies are required to assess the effectiveness and validity of pulse oximetry in determining pulp vitality in traumatized teeth.
Opinions and attitudes of endodontists and general dental practitioners in the UK towards the intracanal fracture of endodontic instruments: part 1
Authors: Madarati A. A. , Watts D. C. , Qualtrough A. J. E. 
Published: June 2008

AbstractAim  To investigate the attitudes and opinions of general dental practitioners (GDPs) and endodontists in the UK towards fracture of endodontic instruments. It was hypothesized that there would be no significant difference between GDPs and endodontists regarding their experience of fracture of endodontic instruments.Methodology  A pilot questionnaire was carried out on 20 postgraduate dental students to ensure that the questions were easily understood. This was followed by a further pilot survey on a group of GDPs and endodontists (50) to facilitate sample size calculation. The sample size comprised 330 systematically selected GDPs, and all endodontic specialists working in the UK (170). The questionnaire comprised both close‐ended and partially close‐ended questions in four categories: demographics; pattern of practice and experience of instrument fracture; management of fractured instruments; and unsuccessful management of fractured instruments. Nonrespondents were sent another two mailings (first and second reminders). After collecting the responses, data were analysed using chi‐square and Linear‐by‐Linear Association tests at the 0.05 level of significance.Results  The overall response rate was 75% (82.82% for endodontists and 70.92% for GDPs). Overall, 88.8% of respondents had experienced fractured instruments with a significantly higher proportion of endodontists (94.8%) compared with that of GDPs (85.1%).Conclusion  Both endodontists and GDPs were aware of most factors contributing to endodontic instrument fracture. With experience and knowledge, fracture of endodontic instruments was associated with the number of root canal treatments performed.
The determinants of nurses’ therapeutic attitude to patients who use illicit drugs and implications for workforce development
Authors: Ford Rosemary , Bammer Gabriele , Becker Niels 
Published: June 2008

Aim.  To examine the determinants of generalist nurses’ therapeutic attitude to patients who use illicit drugs, and to model workforce development initiatives.Background.  Individuals who use illicit drugs rely heavily on healthcare in emergency departments and inpatient hospital wards. Little is known about the determinants of generalist nurses’ therapeutic attitude to provide care, therefore limiting our understanding of the important issues for workforce development.Design.  The study was a cross‐sectional survey of registrants on the Australian Capital Territory Nurses Registration Roll 2002 (N = 3241, 50% response rate). The associations between variables and nurses’ therapeutic attitude were examined by multi‐variable linear regression analysis.Method.  Nurses’ therapeutic attitude was assessed using a modified version of the Alcohol and Alcohol Problems Perception Questionnaire. Personal characteristics, attitudes to illicit drugs and professional practice variables such as drug and alcohol education, experience with the patient group and role support were examined using a mix of standardised and new questions.Results.  Professional practice variables explained 53% of the variation of nurses’ therapeutic attitude, the most important being role support. Although a negative attitude to illicit drugs had a statistically significant association with therapeutic attitude, it added less than 1% to the variation explained. Personal characteristics showed no association.Conclusions.  Generalist nurses struggle to provide care to this patient group. Role support was found to be the strongest driver of nurses’ therapeutic attitude, and workplace illicit drug education was only useful in combination with high role support.Relevance to clinical practice.  Nurses’ caring role with patients who use illicit drugs is complex and demanding. Nursing workforce development must focus on increasing nurses’ role support, in terms of appropriately skilled staff readily available for consultation and advice. Support for nurses, in the form of evidence‐based practice standards and appropriate time allocation, is also important.
Association of spinal deformity and vaccine‐induced abdominal lesions in harvest‐sized Atlantic salmon, Salmo salar L.
Authors: Aunsmo A , Guttvik A , Midtlyng P J , Larssen R B , Evensen Ø , Skjerve E 
Published: June 2008

AbstractSpinal deformities in Atlantic salmon, Salmo salar L., have been described as a disease of multifactorial origin for which vaccines and time of vaccination have been suggested as risk factors. A vaccine efficacy trial where spinal deformity became evident was continued by the observational study reported here. In the preharvest part of the study 17 months post‐sea transfer, there was a prevalence of 11.3% spinal deformity, with deformities present only in one vaccine group indicating a strong vaccine involvement. At slaughter, the prevalence of spinal deformities was 11.7%, and deformed fish had only 62% of normal slaughter weight. Visual analogue scales (VAS) were used for continuous recordings of vaccine‐induced abdominal lesions and deformity. A logistic regression model associating presence of spinal deformity with markers of abdominal lesions was developed. The odds ratio for spinal deformity was 5.7 (95% CI: 3.4–9.4) for each unit increase in adhesion score (0–6) and 4.9 (2.9–3.4) for each unit increase in melanin on abdominal organs (0–3). Lesions in the dorsal caudal part of the abdomen gave an odds ratio for spinal deformity of 2.2.
Effect of dietary administration of Porphyridium cruentum on the respiratory burst activity of sole, Solea senegalensis (Kaup), phagocytes
Authors: Díaz‐Rosales P , Chabrillón M , Abdala R T , Figueroa F L , Balebona M C , Moriñigo M A 
Published: June 2008

AbstractThe stimulatory effect of the red microalga Porphyridium cruentum on respiratory burst activity of sole phagocytes was evaluated in vivo. Oral administration of a diet supplemented with lyophilized P. cruentum cells (10 g kg−1) stimulated respiratory burst activity after 4 weeks feeding in sole vaccinated with Photobacterium damselae subsp. piscicida bacterin.
Plasmodium falciparum origin recognition complex subunit 5: functional characterization and role in DNA replication foci formation
Authors: Gupta Ashish , Mehra Parul , Dhar Suman Kumar 
Published: June 2008

SummaryThe mechanism of DNA replication initiation and progression is poorly understood in the parasites, including human malaria parasite Plasmodium falciparum. Using bioinformatics tools and yeast complementation assay, we identified a putative homologue of Saccharomyces cerevisiaeorigin recognition complex subunit 5 in P. falciparum (PfORC5). PfORC5 forms distinct nuclear foci colocalized with the replication foci marker proliferating cell nuclear antigen (PfPCNA) and co‐immunoprecipitates with PCNA during early‐to‐mid trophozoite stage replicating parasites. Interestingly, these proteins separate from each other at the non‐replicating late schizont stage, citing the evidence of the presence of both PCNA and ORC components in replication foci during eukaryotic DNA replication. PfORC1, another ORC subunit, colocalizes with PfPCNA and PfORC5 at the beginning of DNA replication, but gets degraded at the late schizont stage, ensuring the regulation of DNA replication in the parasites. Further, we have identified putative PCNA‐interacting protein box in PfORC1 that may explain in part the colocalization of PfORC and PfPCNA. Additionally, use of specific DNA replication inhibitor hydroxyurea affects ORC5/PCNA foci formation and parasitic growth. These results strongly favour replication factory model in the parasites and confer great potential to understand the co‐ordination between ORC and PCNA during eukaryotic DNA replication in general.
Functional characterization of cohesin subunit SCC1 in Trypanosoma brucei and dissection of mutant phenotypes in two life cycle stages
Authors: Gluenz Eva , Sharma Reuben , Carrington Mark , Gull Keith 
Published: June 2008

SummaryIn yeast and metazoa, structural maintenance of chromosome (SMC) complexes play key roles in chromosome segregation, architecture and DNA repair. The main function of the cohesin complex is to hold replicated sister chromatids together until segregation at anaphase, which is dependent on proteolytic cleavage of the cohesin subunit SCC1. Analysis of trypanosomatid genomes showed that the core cohesin and condensin complexes are conserved, but SMC5/6 is absent. To investigate the functional conservation of cohesin in eukaryotes distantly related to yeast and metazoa, we characterized the Trypanosoma brucei SCC1 orthologue. TbSCC1 is expressed prior to DNA synthesis at late G1, remains in the nucleus throughout S‐ and G2‐phases of the cell cycle and disappears at anaphase. Depletion of SCC1 by RNAi or expression of a non‐cleavable SCC1 resulted in karyokinesis failure. Using the dominant negative phenotype of non‐cleavable SCC1 we investigated checkpoint regulation of cytokinesis in response to mitosis failure at anaphase. In the absence of chromosome segregation, procyclic trypanosomes progressed through cytokinesis to produce one nucleated and one anucleate cell (zoid). In contrast, cytokinesis was incomplete in bloodstream forms, where cleavage was initiated but cells failed to progress to abscission. Kinetoplast duplication was uninterrupted resulting in cells with multiple kinetoplasts and flagella.
Transcriptional wiring of the TOL plasmid regulatory network to its host involves the submission of the σ54‐promoter Pu to the response regulator PprA
Authors: Vitale Elena , Milani Andrea , Renzi Francesco , Galli Enrica , Rescalli Emanuela , De Lorenzo Víctor , Bertoni Giovanni 
Published: June 2008

SummaryImplantation of the regulatory circuit of the degradation pathway of TOL plasmid pWW0 in the native transcriptional network of the host Pseudomonas putida involves interplay between plasmid‐ and chromosome‐encoded factors. We have employed a reverse genetics approach to investigate such a molecular wiring by identifying host proteins that form stable complexes with Pu, the σ54‐dependent promoter of the upper TOL operon of pWW0. This approach revealed that the Pu upstream activating sequences (UAS), the target sites of the cognate activator XylR, form a specific complex with a host protein which, following DNA affinity purification and mass spectrometry analysis, was identified as the LytTR‐type two‐component response regulator PprA. Directed inactivation of pprA resulted in the upregulation of the Pu promoter in vivo, while expression of the same gene from a plasmid vector strongly repressed Pu activity. Such a downregulation of Pu by PprA could be faithfully reproduced both in vitro with purified components and in an in vivo reporter system assembled in Escherichia coli. The overlap of the PprA and XylR binding sites suggested that the basis for the inhibitory effect on Pu was a mutual exclusion mechanism between the two proteins to bind the UAS. We argue that the binding of the response regulator PprA to Pu (a case without precedents in σ54‐dependent transcription) helps to anchor the TOL regulatory subnetwork to the wider context of the host transcriptome, thereby allowing the entry of physiological signals that modulate the outcome of promoter activity.
EsaC substrate for the ESAT‐6 secretion pathway and its role in persistent infections of Staphylococcus aureus
Authors: Burts Monica L. , DeDent Andrea C. , Missiakas Dominique M. 
Published: June 2008

Summary Staphylococcus aureus encodes the specialized secretion system Ess (ESAT‐6 secretion system). The ess locus is a cluster of eight genes (esxAB, essABC, esaABC) of which esxA and esxB display homology to secreted ESAT‐6 proteins of Mycobacterium tuberculosis. EsxA and EsxB require EssA, EssB and EssC for transport across the staphylococcal envelope. Herein, we examine the role of EsaB and EsaC and show that EsaB is a negative regulator of EsaC. Further, EsaC production is repressed when staphylococci are grown in broth and increased when staphylococci replicate in serum or infected hosts. EsaB is constitutively produced and remains in the cytoplasm whereas EsaC is secreted. This secretion requires an intact Ess pathway. Mutants lacking esaB or esaC display only a small defect in acute infection, but remarkably are unable to promote persistent abscesses during animal infection. Together, the data suggest a model whereby EsaB controls the production of effector molecules that are important for host pathogen interaction. One such effector, EsaC, is a secretion substrate of the Ess pathway and implements its pathogenic function during infection.