bluuebunny/crossref_metadata_2025_split huggingface dataset:
The learning organization information system (LOIS): looking for the next generation
Authors: Williamson Adrian , Iliopoulos Constantinos 
Published: March 2003

Abstract.This paper explores the notion that the next generation of information systems will focus on supporting organizational learning. The paper suggests that the increasingly successful automation of procedural work will lead to pressure on organizations to improve performance through enhanced support for knowledge work. A set of outline requirements for the learning organization information system (LOIS) is then proposed using recent research findings from computer supported co‐operative working and organizational learning. The computerized on‐line journal from this research is described. This journal provides transparent capture of episodes of work and it is argued that the general principles established could support LOIS by helping to provide a richly defined organizational memory. The journal supports collaborative working through the use of groupware, which manages the sharing of, and learning from, journal contents. This can facilitate the retention of not only data and information, but also the inquiry process that produced them. The paper concludes that LOIS will be a self‐organizing system, focussing on knowledge work, learning and using advanced technologies drawn from ubiquitous computing. A view of a system that moves towards this aim is presented. Future topics for research are identified, and a natural language approach to knowledge asset management is discussed briefly. In closing, it is argued that LOIS is an important future vision for organizations operating in the information age.
Molecular analysis and chromosome mapping of the H2A, H3 and H4 histone genes from the malaria vector Anopheles gambiae
Authors: Reynaud E. , Vázquez M. , Zurita M. 
Published: March 2003

AbstractIn this we report the cloning and analysis of PCR generated fragments that encode H2A, H3 and H4 histone genes from the malaria vector An. gambiae. Sequence analysis indicated that some conservative changes are present in the An. gambiae H2A and H4 genes as compared with histone genes from other organisms. Divisional mapping showed that these genes map in division 20 on the left arm of the second chromosome. Southern blot experiments and the molecular characterization of the genomic fragment containing the H2A, H2B, H3 and H4 genes showed that they are organized in a cluster with an orientation different from the one found in other dipterans.
Recombinant juvenile hormone esterase, an effective tool for modifying juvenile hormone‐dependent expression of the early trypsin gene in mosquitoes
Authors: Edgar K. A. , Noriega F. G. , Bonning B. C. , Wells M. A. 
Published: March 2003

AbstractThe study of the changes in the steady‐state levels of the early trypsin (ET) messenger RNA (mRNA) was used as a sensitive assay for measuring the effects of recombinant juvenile hormone esterase (rJHE) on juvenile hormone (JH)‐dependent gene expression in mosquitoes. ET is a female‐specific protease present in the midgut of the yellow fever mosquito Aedes aegypti during the first few hours after ingestion of a blood meal. Transcription of the early trypsin gene is part of the normal postemergence maturation of the midgut in the adult female, and it is regulated by JH. JHE was cloned from Heliothis virescens and expressed in a baculovirus vector. Injection of rJHE into mosquitoes resulted in an increase of JHE activity in the haemolymph. Injection of rJHE into newly emerged adult females delayed the normal increase in steady‐state levels of ET mRNA observed in controls. Topically applied methoprene (a JH analogue) reversed the effect of rJHE. Injection of increasing concentrations of rJHE into 3‐day‐old unfed females resulted in a dose‐dependent decrease in the steady‐state levels of ET mRNA after 24 h. The effect of rJHE was transient, once the enzyme was cleared (72 h after injection), the steady‐state levels of ET mRNA were restored. The injection of rJHE is an effective tool for modifying JH‐dependent expression of the early trypsin gene in mosquitoes.
Molecular cloning and characterization of a metal responsive Aedes aegypti intestinal mucin cDNA
Authors: Rayms‐Keller A. , McGaw M. , Oray C. , Carlson J. O. , Beaty B. J. 
Published: March 2003

AbstractWe have isolated a cDNA from Aedes aegypti that is transcribed in the larval midgut in response to metal exposure, and in the adult female midgut in response to iron or cadmium exposure, or a blood meal. The cDNA encodes a protein, designated Aedes aegypti intestinal mucin 1 (AEIMUC1), which has similarities with invertebrate intestinal mucins and peritrophins, and vertebrate mucins. Proline, serine and threonine comprise 30% of the amino acid composition of AEIMUC1, a characteristic of mucins. AEIMUC1 contains three cysteine‐rich domains, two of which flank a proline/serine/threonine‐rich domain, a feature shared by many mucin genes. This is the first report on the isolation of a metal‐responsive gene from an aquatic insect.
Distribution of genetic variation among chromosomal forms of Anopheles gambiae s.s.: introgressive hybridization, adaptive inversions, or recent reproductive isolation?
Authors: Black W. C. , Lanzaro G. C. 
Published: March 2003

AbstractA series of four papers in this issue explores the reproductive status of the five chromosomal forms of An. gambiae s.s. using molecular techniques to examine the variation among twelve different genes located throughout the An. gambiae s.s. genome. Results of these and previous studies are consistent with a hypothesis of at least partial barriers to gene flow between some chromosomal forms in the Ivory Coast and other West African countries to the north and west, but introgression between S and M types in Benin and countries to the east. Collectively, these studies indicate the need for a broader geographical sampling of An. gambiae s.s., increased research on mechanisms of prezygotic reproductive isolation and field‐based studies of survival and fecundity in hybrids to test for postzygotic reproductive isolation.
Expression and induction of three family 4 cytochrome P450 (CYP4)* genes identified from insecticide‐resistant and susceptible western corn rootworms, Diabrotica virgifera virgifera
Authors: Scharf M. E. , Parimi S. , Meinke L. J. , Chandler L. D. , Siegfried B. D. 
Published: March 2003

AbstractWe have previously determined that cytochrome P450‐based oxidation is involved in resistance to the insecticides methyl parathion and carbaryl in geographically distinct Nebraska western corn rootworm populations. Three new family 4 cytochrome P450 (CYP4) gene fragments (CYP4AJ1, CYP4G18 and CYP4AK1) were cloned and sequenced from insecticide‐resistant and ‐susceptible western corn rootworms. Insecticide bioassays indicated the resistant population employed in this study was significantly resistant to the insecticides methyl parathion and carbaryl. CYP4AJ1 and CYP4G18 were cloned from both genomic PCR and RT‐PCR products, although only CYP4AJ1 contains an intronic region. Alignments of inferred amino acid sequences with other homologous insect CYP4 genes indicates a high degree of similarity. Northern analysis concurrently employing mixed probes representing each of the three rootworm CYP4 fragments identified increased mRNA transcript signals (i) in resistant rootworms and (ii) following induction by the P450 inducer pentamethyl benzene. These results support our previous documentation of P450‐based insecticide resistance and suggest increased CYP4 transcript abundance can serve as a molecular resistance‐associated marker.
Expression and function of the Drosophila melanogaster ADH in male Ceratitis capitata adults: a potential strategy for medfly genetic sexing based on gene‐transfer technology
Authors: Christophides G. K. , Savakis C. , Mintzas A. C. , Komitopoulou K. 
Published: March 2003

AbstractThe aim of development of a Mediterranean fruit fly Ceratitis capitata genetic sexing strain derives from the large scale SIT programmes being carried out to control this pest. Toward this direction, we present here the male‐specific expression of the Drosophila melanogaster alcohol dehydrogenase (ADH) in medfly transgenic adults generated by Minos‐mediated germ line transformation. This expression pattern is obtained by using a promoter fragment of the male‐specific gene MSSP‐α2 of the medfly. We show that the heterologous enzyme is functional in the medfly oxidizing both ethanol and 2‐propanol. Although leading to an approximately twofold increase of total ADH activity in male compared to female transgenic adults, these expression levels are not enough for performing genetic sexing when high doses of environmental alcohol are applied. This could be achieved either by further enhancement of the transgene expression or by generating an Adh− line to host the Minos insertions.
Paraphyly in Hawaiian hybrid blowfly populations and the evolutionary history of anthropophilic species
Authors: Stevens J. R. , Wall R. , Wells J. D. 
Published: March 2003

AbstractComplementary nuclear (28S rRNA) and mitochondrial (COI + II) gene markers were sequenced from the blowflies,Lucilia cuprinaandLucilia sericata, from Europe, Africa, North America, Australasia and Hawaii. Populations of the two species were phylogenetically distinct at both genes, with one exception. HawaiianL. cuprinapossessed typicalL. cuprina‐type rRNA, but hadL. sericata‐type mitochondrial (COI + II) sequences. An explanation for this pattern is that Hawaiian flies are hybrids and comparison of observed levels of sequence divergence to possible introduction events, e.g. Polynesian colonization, suggests that HawaiianL. cuprinamay be evolving rapidly. Moreover, the monophyly of these flies also suggests that theL. sericatamtDNA haplotype was apparently fixed in HawaiianL. cuprinaby lineage sorting, indicating a population bottleneck in the evolutionary history of these island flies.
Induction of the white egg 3 mutant phenotype by injection of the double‐stranded RNA of the silkworm white gene
Authors: Quan G. X. , Kanda T. , Tamura T. 
Published: March 2003

AbstractInjection of double‐stranded RNA (dsRNA) corresponding to the silkworm white gene (Bmwh3) into preblastoderm eggs of the wild‐type silkworm induced phenotypes similar to those observed with mutants of the white egg 3 locus (10–19.6). The induced phenotypes were characterized by the presence of white eggs and translucent larval skin. Northern analysis showed that the expression of the endogenous Bmwh3 gene in the injected embryos was distinctly depressed. Furthermore, the injection of the GFP dsRNA inhibited the expression of the GFP gene from a plasmid co‐injected with the dsRNA but did not depress the expression of the Bmwh3 gene. These findings demonstrate that sequence‐specific RNA interference occurred in the silkworm. We conclude from the results that the RNA interference can be applied as a tool for the analysis of the gene function in the lepidopteran insects.
cDNA cloning of biotransformation enzymes belonging to the cytochrome P450 family in the antennae of the noctuid moth Mamestra brassicae
Authors: Maïbèche‐Coisne M. , Jacquin‐Joly E. , François M. C. , Nagnan‐Le Meillour P. 
Published: March 2003

AbstractThe involvement of cytochrome P450 enzymes in olfaction was demonstrated in vertebrates some time ago. In insects these enzymes are well known for their role in insecticide resistance, but the involvement of P450 in pheromone degradation was only recently demonstrated. Using a PCR strategy, we have isolated two cDNAs from the antennae of the cabbage armyworm Mamestra brassicae–CYP4L4 and CYP4S4– which encode microsomal P450s. CYP4S4 expression is restricted to the antennae, whereas CYP4L4 is also found in the proboscis and legs. Moreover, the two genes are strongly expressed in one type of sensory unit of the antennae – the sensilla trichodea – which are tuned to the detection of odourants. The putative function of the corresponding enzymes is discussed with regard to their respective expression patterns.
Incidence of four canals in root‐canal‐treated mandibular first molars in a Saudi Arabian sub‐population
Authors: Al‐Nazhan S. 
Published: March 2003

Aim The aim of this in‐vivo study was to assess the incidence of three roots and four root canals in clinical cases of root‐treated mandibular first molars in a Saudi Arabian population.Methodology A clinical study of 251 root‐canal treated permanent mandibular first molars was conducted The teeth were examined clinically and radiographically.Results The results showed that 5.97% of the examined teeth had three roots, 57.76% had four root canals (two mesial and two distal) and 42.3% had three root canals (two mesial and one distal).Conclusions The occurrence of four root canals in the mandibular first molar of a Saudi Arabian subpopulation was high.
The effects of Ledermix paste on discolouration of mature teeth
Authors: Kim S. T. , Abbott P. V. , McGinley P. 
Published: March 2003

AbstractAimThe aims of this study were to: (i) investigate the effects of Ledermix paste as an intracanal medicament on discolouration of mature teeth, (ii) examine whether the discolouring effects were related to the method of application, and (iii) examine the effects of sunlight upon discolouration of mature teeth.MethodologyThe root canals of 45 mature extracted human teeth were prepared and filled with either Ledermix paste, calcium hydroxide [Ca(OH)2], or saline. In group 1, Ledermix paste was placed apical to the cemento‐enamel junction (CEJ), whilst in groups 2 and 3 the paste filled the entire pulp chamber and root canals. In group 4, a Ca(OH)2 and methyl cellulose paste and, in group 5, saline (control) were allowed to fill the pulp chamber and the root canals. Group 3 teeth were kept in the dark and the other groups were exposed to indirect sunlight for 12 weeks.ResultsAfter 12 weeks, sunlight exposure had caused dark grey‐brown staining of the teeth in the Ledermix groups, but this did not occur when the teeth were kept in the dark. More severe staining was noted when Ledermix paste filled the pulp chamber than when the paste was restricted to below the CEJ.ConclusionsIt was concluded that Ledermix paste may cause discolouration of teeth. Such effects can be minimized if placement of the paste is restricted to below the gingival margin. Clinicians should ensure that Ledermix paste is not left on the walls of access cavities.
In vitro evidence that lipopolysaccharide of an oral pathogen leaks from root‐end filled teeth
Authors: Laghios C. D. , Cutler C. W. , Gutmann J. L. 
Published: March 2003

AbstractAimThe ability to achieve a complete apical seal of the root canal system is thought to be important in the success of non‐surgical and surgical endodontics. The aim of this study was to establish whether or not root‐end filled teeth allow leakage of lipopolysaccharide (LPS) from a known oral pathogen in vitro.MethodologyLipopolysaccharide (LPS) from a virulent strain of Porphyromonas gingivalis (P. gingivalis) (A7436 from patient with refractory periodontitis), was isolated by the Westphall and Jann technique, dialysed extensively, lyophilyzed, resuspended in distilled water and analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). Root canals from 10 teeth were instrumented endodontically and the apical 3 mm of resected roots were filled with gutta‐percha. The teeth were mounted in 12 mL polypropylene vials by using sticky wax and root surfaces were covered with two layers of nail varnish. Teeth were filled with 3.3 mg mL–1 LPS and the vials filled with 11 mL of Tris Buffered Saline (TBS) containing 0.05% sodium azide. Both positive and negative controls were run in parallel with the experimental specimens. Aliquots were removed each day and subjected to slot blot analysis to quantitate the amount of LPS that had leaked into the bottom of the vials. The density of slots was analyzed using a laser densitometer and regression analysis was used to generate a standard curve, confidence intervals and experimental values.ResultsThe data indicated that teeth obturated apically with gutta‐percha leaked, whilst no LPS leakage was detected in teeth covered completely with nail varnish (P < 0.05).Conclusions In vitro teeth with gutta‐percha root‐end fills can permit leakage of LPS from an identified oral pathogen.
Efficacy of Quantec rotary instruments for gutta‐percha removal
Authors: Bramante C. M. , Betti L. V. 
Published: March 2003

AbstractAimThe purpose of this study was to evaluate Quantec SC rotary instruments for removal of gutta‐percha during retreatment of straight root canals.MethodologyThe root canals of 30 central incisors were instrumented and obturated before the teeth were randomly divided into three groups of 10 specimens each. Quantec SC rotary instruments and a 16 : 1 reduction handpiece powered by an electric motor were then used to remove the gutta‐percha and sealer from canals. A different speed was used in each group (group 1, 350 r.p.m.; group 2, 700 r.p.m.; and group 3, 1500 r.p.m.). The followings factors were evaluated: time taken to reach working length, time for gutta‐percha removal, total time, apically extruded material during filling removal and number of fractured instruments. Radiographs were taken after the filling removal and after the canal wall cleanliness was evaluated. The teeth were grooved longitudinally, divided, and the walls of each half were evaluated visually for cleanliness. They were then digitized using a scanner and the residual debris measured.ResultsThe group in which a speed of 1500 r.p.m. was used had significantly faster treatment than the other groups. The amount of apically extruded material was not significantly different between groups. The only significant difference between groups for canal cleanliness was the middle third by radiographic evaluation: the group of 350 r.p.m. had larger amount of debris than the others. In group 1, six instruments fractured; in group 2, four instruments fractured; and in group 3, one instrument fractured.ConclusionsCleanliness and residual debris were equivalent for each group, but the use of 1500 r.p.m. speed was more rapid and fewer instruments fractured.
The standardized‐taper root canal preparation – Part 1. Concepts for variably tapered shaping instruments
Authors: Buchanan L. S. 
Published: March 2003

Abstract Buchanan LS. The standardized‐taper root canal preparation – Part 1. Concepts for variably tapered shaping instruments. International Endodontic Journal, 33, 516–529, 2000.AimTo introduce the concept of variable taper instruments for predictable and ergonomic root canal preparation, and demonstrate the design features of Greater Taper files.SummaryOptimal root canal shaping is difficult to practice and teach with traditional instruments. Instrument sequences are complex, with up to 18 instruments and 63 procedural stages, providing almost limitless scope for poor results and iatrogenic error.In the first of six articles, Dr Buchanan describes the Variable Taper concept, which grew from such frustrations, and represents a new concept in file design. Milled from NiTi alloys in tapers of 0.06, 0.08, 0.10 and 0.12 mm mm−1, with accessory files for wide canals, their design embodies the key shaping features of adequate coronal enlargement, full deep shape, and predictable apical resistance form case after case. The ease and simplicity of their use is described, and enhanced cleaning and obturation outcomes discussed in relation to their unique design features.Key learning points

Canal preparation is difficult to practice and teach with traditional K‐files and Gates Glidden drills.
Variable Taper files are designed to offer the optimal preparation features of adequate (not excessive) coronal enlargement, full deep shape, and apical resistance form in a simple instrument sequence.
Variable Taper technique is simple to master, and offers predictable cleaning and obturation outcomes, even in inexperienced hands.
Root canal systems of the mandibular and maxillary first permanent molar teeth of South Asian Pakistanis
Authors: Wasti F. , Shearer A. C. , Wilson N. H. F. 
Published: March 2003

AbstractAimThe purpose of the present ex vivo study was to investigate variations in the root canal systems of mandibular and maxillary first permanent molar teeth of South Asian Pakistanis.MethodologyThe root canal systems of a sample of 30 mandibular and 30 maxillary first permanent molar teeth extracted from South Asian Pakistanis were studied using a clearing technique.ResultsThe mesial roots of the mandibular molar teeth typically presented with two canals (97%) of type II, IV or VI configuration. The distal roots of these teeth presented with a single canal (50%) of type I or V configuration or with two canals (50%) of type II, IV or VI. The prevalence of four root canals in two‐rooted mandibular first permanent molar teeth was 47%. In maxillary molar teeth the mesial roots with a single canal (47%) were type I or type V; those with two canals (53%) were type II, IV or type VI. The distal and palatal roots that presented as a single canal (100%) were type I or type V configuration. The prevalence of four root canals in three‐rooted maxillary first permanent molar teeth was 53%.ConclusionIt is concluded that four root canals in mandibular and maxillary first permanent molar teeth of South Asian Pakistanis is a common occurrence. The distribution of the different configurations of root canal systems in this population differed from that in Caucasian groups, suggesting that variations in root canal systems may be attributed to racial divergence.
Effectiveness of oxidative potential water as a root canal irrigant
Authors: Hata G. , Hayami S. , Weine F. S. , Toda T. 
Published: March 2003

AbstractAimThe aim of this study was to evaluate the effectiveness of oxidative potential water (OPW) as an irrigant, based on its ability to remove the smear layer and/or debris from instrumented root canals.MethodologyOne hundred and twenty root canals from extracted human maxillary incisors were instrumented using a conventional step‐back technique with irrigation from sodium hypochlorite (NaOCl) or oxidative potential water (OPW). After instrumentation, the canals were irrigated by syringe or ultrasound using 15% EDTA or OPW as an irrigant. The volume of each irrigant used for syringe irrigation was 10, 20, and 30 mL, respectively, whilst the duration for ultrasonic irrigation was 1, 3, and 5 min, respectively. After irrigation, each root was split longitudinally in two with cutting pliers, and the specimens were prepared for SEM observation. The presence of debris and smear layer on each canal wall was assessed using a three‐point scale for each parameter.ResultsSmear layer was effectively removed with EDTA both introduced via syringe and via ultrasonic irrigation. A similar effect was observed with OPW via syringe irrigation following instrumentation with 5% NaOCl. The canal walls in any of these cases showed open and patent dentinal tubules following smear layer removal. Some specimens irrigated with EDTA exhibited the effect of demineralization on the dentine resulting in funnelling of tubule orifices. Syringe irrigation was more effective in smear layer removal, except for ultrasonic irrigation with 15% EDTA, whilst ultrasonic irrigation was more effective in debris removal including the use of OPW as irrigant following instrumentation with 5% NaOCl. Neither syringe nor ultrasonic irrigation with OPW following instrumentation with OPW removed smear layer or debris effectively.ConclusionsThe most effective irrigation technique for smear removal was 15% EDTA irrigation by means of syringe following instrumentation with 5% NaOCl solution. However, the most effective irrigation technique for debris removal was ultrasonic irrigation regardless of irrigant used. OPW irrigation by means of syringe following instrumentation with 5% NaOCl showed a similar effect to that of 15% EDTA irrigation for removal of smear layer and debris.