bluuebunny/crossref_metadata_2025 huggingface dataset:
Failure Investigation of a Gas Turbine Inlet Weatherhood
Authors: Sykes J. , Allison I. M.
Published: March 2003

Analytical and experimental methods have been used to investigate fatigue failures in the weatherhood protecting the air inlet to an offshore gas turbine power generation unit. A simple method for modelling transverse vibration of the leading edge is described, and the results are compared with experimental measurements made on a prototype installation. Calculation of the stresses induced at the critical locations, where cracking has been observed, suggests the failure should be attributed to aerodynamic excitation of the leading edge.
P–T conditions of decompression of the Limpopo high‐grade terrane: record from shear zones
Authors: Smit C. A. , Van Reenen D. D. , Gerya T. V. , Perchuk L. L.
Published: March 2003

The Southern Marginal Zone of the late Archean Limpopo Belt of southern Africa is an example of a high‐grade gneiss terrane in which both upper and lower crustal deformational processes can be studied. This marginal zone consists of large thrust sheets of complexly folded low‐strain gneisses, bound by an imbricate system of kilometre‐wide deep crustal shear zones characterized by the presence of high‐strain gneisses (‘primary straight gneisses’). These shear zones developed during the decompression stage of this high‐grade terrane. Low‐ and high‐strain gneisses both contain similar reaction textures that formed under different kinematic conditions during decompression. Evidence for the early M1/D1 metamorphic phase (> 2690 Ma) is rarely preserved in low‐strain gneisses as a uniform orientation of relict Al‐rich orthopyroxene in the matrix and quartz and plagioclase inclusions in the cores of early (M1) Mg‐rich garnet porphyroblasts. This rare fabric formed at > 820 °C and > 7.5 kbar. The retrograde M2/D2 metamorphic fabric (2630–2670 Ma) is well developed in high‐strain gneisses from deep crustal shear zones and is microscopically recognized by the presence of reaction textures that formed synkinematically during shear deformation: M2 sigmoid‐shaped reaction textures with oriented cordierite–orthopyroxene symplectites formed after the early M1 Mg‐rich garnet porphyroblasts, and syn‐decompression M2 pencil‐shaped garnet with oriented inclusions of sillimanite and quartz formed after cordierite under conditions of near‐isobaric cooling at 750–630 °C and 6–5 kbar. The symplectites and pencil‐shaped garnet are oriented parallel to the shear fabric and in the stretching direction. Low‐strain gneisses from thrust sheets show similar M2 decompression cooling and near‐isobaric cooling reaction textures that formed within the same P–T range, but under low‐strain conditions, as shown by their pseudo‐idioblastic shapes that reflect the contours of completely replaced M1 garnet and randomly oriented cordierite–orthopyroxene symplectites. The presence of similar reaction textures reflecting low‐strain conditions in gneisses from thrust sheets and high‐strain conditions in primary straight gneisses suggests that most of the strain during decompression was partitioned into the bounding shear zones. A younger M3/D3 mylonitic fabric (< 2637 Ma) in unhydrated mylonites is characterized by brittle deformation of garnet porphyroclasts and ductile deformation of the quartz–plagioclase–biotite matrix developed at < 600 °C, as the result of post‐decompression shearing under epidote–amphibolite facies conditions.
Fluid inclusions in coesite‐bearing eclogites and jadeite quartzite at Shuanghe, Dabie Shan (China)
Authors: Fu B. , Touret J.L.R. , Zheng Y.‐F.
Published: March 2003

Fluid inclusions in coesite‐bearing eclogites and jadeite quartzite at Shuanghe in Dabie Shan, East‐central China, have preserved remnants of early, prograde and/or peak metamorphic fluids, reset during post‐UHP (ultrahigh‐pressure) metamorphic uplift. Inclusions occur in several minerals (e.g. omphacite & epidote), notably as isolated, primary inclusions in quartz included in various host minerals. Two major fluid types have been identified: non‐polar fluid species (N2 or CO2) and aqueous, the latter is by far the most predominant. Aqueous fluids cover a wide range of salinity, from halite‐bearing brines to low salinity fluids. For non‐polar fluids, few N2 inclusions occur in undeformed eclogite, whereas a number of CO2‐rich inclusions have been found in microshear zones of eclogite or jadeite quartzite in close proximity to marble occurrences.

The primary character of N2 and high‐salinity aqueous inclusions indicates that they are remnants from UHP metamorphic fluids and for some there is the distinct possibility that they are ultimately derived from pre‐metamorphic fluids. This conclusion is supported by the preservation, in some samples, of microdomains containing synchronous inclusions of variable salinities, which tend to relate to the chemical composition of the host crystal. Carbonic fluids may be derived from neighbouring rocks, notably marble and carbonate‐bearing metasediments, during post‐metamorphic uplift. During post‐UHP exhumation, a limited decrease of the fluid density has occurred, with formation of new sets of fluid inclusions. Fluid movements, however, remained exceedingly limited, at the scale of the enclosing crystal.
Metamorphic processes: a celebration of the career contribution of Ron Vernon
Authors: Brown Michael , Clarke Geoffrey L.
Published: March 2003

This Special Issue is in celebration of the career contribution of Ron Vernon. It arises from the ‘Ron Vernon Symposium’, which was held as part of the 15th Australian Geological Convention in Sydney in 2000. To date Ron has published more than one hundred scientific papers, several books and contributed widely to international conferences. He is the doyen in the multidisciplinary field of microstructures, which spans petrology and structural geology. However, Ron's range is phenomenal, and he has contributed to many aspects of metamorphism, magmatism and rock deformation. He has drawn on data from his work in these areas to contribute widely to understanding thermal regimes, crustal evolution and tectonics, as exemplified by his ideas about HTLP metamorphism and emplacement of granites. Ron has followed the scientific method in his work; it has led him to many innovative interpretations, some of which undermined established dogma. By example, Ron has been a positive role model for the younger generation. However, for the older generation, he has been something of a bête noire! The papers in this Special Issue cover the range from low‐ to high‐grade metamorphism, from metasomatism to melting, from microstructures to tectonics, and from fieldwork to experiments. It is our hope that in reading them you will take time to think about what has been achieved in the past 40 years, and use this as motivation for what remains to be done.
Virtual reality and hypermedia in learning to use a turning lathe
Authors: Antonietti A. , Imperio E. , Rasi C. , Sacco M.
Published: March 2003

Abstract A Virtual reality environment with hypermedia was designed to help undergraduates understand the structure and functioning of a turning lathe. Study 1 was carried out with 30 novice students and Study 2 involved 24 students attending a machining course. These studies demonstrated that the virtual lathe can foster the comprehension of some core machining concepts. Further, the studies suggest that novice students benefit most from earlier free navigation of the virtual environment whereas expert students benefit from an analysis of the hypermedia.
How trainee teachers of IT approach teaching their subject
Authors: Hammond M. , Mumtaz S.
Published: March 2003

Abstract  This paper explores the nature of Information Technology (IT) as a separate subject in the secondary school curriculum. It reports on research carried out with a cohort of specialist IT post‐graduate trainee teachers at a local university. The paper explores IT trainees' approach to teaching their subject and describes their strong focus on purpose when teaching IT. Important characteristics of the purposeful approach are the use of authentic data; the transformation of data by pupils; and a focus on problem solving within a context to which pupils can relate. However in their work in schools, trainees found constraints on developing a strong focus on purpose in their lessons. They were encouraged to experiment but felt they needed more support to carry out purposeful activities with pupils. The implications of this research on teacher training and on the value of IT as a curriculum subject are discussed.
Correcting computer‐based assessments for guessing
Authors: Harper R.
Published: March 2003

Abstract  A statistical approach to calculating the proportion of the mark that is due to guessing is presented. The use of this statistical approach using formulae in a spreadsheet to calculate the contribution to the assessment mark from guessing is demonstrated. The relationship between the learning objectives and multiple‐choice assessments is considered. It is identified that in some cases maximum performance should not be set at a mark of 100% but that an allowance should be made for the maximum expected performance based on the learning objectives. The use of formulae in a spreadsheet to convert the raw assessment marks into marks or grades corrected for guessing or additionally allowing for the maximum expected mark is demonstrated.
Bootstrapping in a language learning environment
Authors: Wible D. , Kuo C‐H. , Tsao N‐L. , Liu A. , Lin H‐L.
Published: March 2003

Abstract  This paper addresses a fundamental dilemma in the design of intelligent language learning environments: the more freedom a system offers to learners in the use of the target language, the more unwieldy the data is which the learners produce and the less able the system is to support inferences about learners from that data. It is shown how in a platform where learners and teachers interact, the teachers' feedback which is archived in the system and indexed to the learners' target language production can constitute affordances that support a process of bootstrapping from raw language output to potential insights into the learners' interlanguage and gaps in their grasp of the target language. The approach is illustrated with three types of learner errors uncovered in the corpus of learner English through this bootstrapping heuristic.
ICT skills learning strategies and histories of trainee teachers
Authors: Taylor L.
Published: March 2003

Abstract As yet, there is only a small volume of research on how trainee teachers develop their personal ICT skills. This paper reports the findings of a one‐year action research study which explored in detail the processes by which a cohort of postgraduate teacher trainees learned these skills. Learning histories before the course were found to be complex and varied. Trainees reported that they consciously drew on a repertoire of learning strategies whilst developing their skills, and a set of factors including previous experience, match of learning opportunities with preferences and software attributes affected a successful learning outcome. An initial model of the learning process was completely revised to reflect the findings. Implications of this research for those working with trainees or other adults who are developing their ICT skills are suggested
A comparison of temporal speech and text cueing in educational multimedia
Authors: Mann B. , Newhouse P. , Pagram J. , Campbell A. , Schulz H.
Published: March 2003

This research focused on the prediction that children in their school setting would learn more from educational multimedia when critical information was presented as spoken instead of textual cues. Analyses of a study (n= 42) showed that 12‐year‐olds did not learn any more from temporal speech cueing than from temporal text cueing. The findings suggest that multimedia learning for children is a different kind of learning experience than for adults or older adolescents. The results indicate underdeveloped executive control of the referential connections in the children's working memory between reading screen text while listening to spoken cues, and between watching on‐screen animations play while listening to spoken cues. Further study is warranted. Implications may be derived for educational multimedia research in school settings.
The influence of IT: perspectives from five Australian schools
Authors: Ainley J. , Banks D. , Fleming M.
Published: March 2003

Abstract Information and Communication Technologies (ICT) are now widespread in Australian schools but with variation in how, where, when and how much they are used. Computers may be located in a computer laboratory, distributed throughout the school, or students may use their own laptop computers. IT may be a subject in its own right or ICT may be used across all areas of the curriculum. It is how ICT is used in the school setting that is important in providing students with the skills to be participate in a ‘knowledge society’. This paper examines the ways in which information and communication technologies influence teaching and learning in five Australian schools. Data were gathered through observation, interviews and document analysis in schools operating at the elementary and secondary grades in relatively technology rich environments. Each of the schools participated in the Australian component of the Second Information Technology in Education Study– Module 2 (SITES‐M2) of innovative pedagogical practices. Several of the studies were of specific projects where ICT was the key enabler of the learning programme. Others focused on an entire school's approach to ICT as an agent for changed approaches to learning.
Sex chromosome variation and cytotaxonomy of the onchocerciasis vector Simulium squamosum in Cameroon and Nigeria
Authors: Traore‐Lamizana M. , Somiari S. , Mafuyai H. B. , Vajime C. G. , Post R. J.
Published: March 2003

Abstract. On the basis of sex chromosome variation, three cytotypes of Simulium squamosum (Enderlein) (Diptera: Simuliidae) are described from Cameroon and Nigeria. Simulium squamosum A is the typical form as originally described by Vajime & Dunbar (1975) with chromosome I as the sex chromosome. It occurs throughout most of Cameroon and south‐east Nigeria. A second cytotype, S. squamosum B, is described from the river Sanaga (Cameroon). It also has chromosome I as the sex chromosome, but the nature of the sex differential region is different. Simulium squamosum C has no sex‐linked chromosomal rearrangements. It is widespread in Nigeria and occurs near Mount Cameroon, where it seems to hybridize with S. squamosum A.
Control of the buffalo fly Haematobia irritans exigua in India, using the pyrethroids deltamethrin and fenvalerate
Authors: Parashar B. D. , Gupta G. P. , Rao Y. V. S. , Rao K. M.
Published: March 2003

Abstract. The effectiveness of two pyrethroids, fenvalerate and deltamethrin, against the fly Haematobia irritans exigua de Meijere (Diptera: Muscidae) on buffalo was considered in a field trial. Fenvalerate provided 100% control for 1, 2 and 4 weeks at concentrations of 0.03, 0.04 and 0.05%, respectively. Concentrations of 0.01 and 0.02% were less effective. One hundred percent control of this fly was obtained with deltamethrin for 2, 3 and 6 weeks at concentrations of 0.003, 0.004 and 0.005%, respectively. Deltamethrin concentrations of 0.001% and 0.002% achieved fly control for only 1–2 weeks, respectively.
Laboratory and field evaluation of insect repellents as larvicides against the mosquitoes Aedes albopictus and Anopheles albimanus
Authors: Xue R.‐D. , Barnard D. R. , Ali A.
Published: March 2003

Abstract. Acute toxicity and persistence of three insect repellents, deet and two piperidines (AI3‐35765 and AI3‐37220), were evaluated against mosquito larvae of Aedes albopictus (Skuse) and Anopheles albimanus Wiedemann (Diptera: Culicidae) in the laboratory, and against natural populations of Ae. albopictus in the field. In laboratory studies, the LC50 values of the repellents for first instars ranged between 0.005 and 0.021% (Ae. albopictus) and between 0.01 and 0.014% (An. albimanus) and, for fourth instars, between 0.019 and 0.034% (Ae. albopictus) and between 0.015 and 0.024% (An. albimanus). A 0.1% concentration of deet caused 90–100% mortality in first‐instar Ae. albopictus for 4 weeks, whereas AI3‐35765 and AI3‐37220 at the same concentration killed 95–100% of larvae for 12 weeks and 98–100% of larvae for 33 weeks post‐treatment, respectively. Deet and AI3‐35765 at 0.1% concentration resulted in complete mortality of first‐instar An. albimanus for 3 weeks post‐treatment, whereas AI3‐37220 resulted in 91–99% larval mortalities for 35 weeks post‐treatment. A 0.1% concentration of AI3‐37220 provided 77–98% larval mortality for 20 weeks and 63–97% larval mortality for 12 weeks post‐treatment, respectively, against fourth‐instar Ae. albopictus and An. albimanus.

In the field, in artificial containers, the reduction of Ae. albopictus larvae caused by deet, AI3‐35765 and AI3‐37220 was 88–95% for 3–4 weeks, 98–100% for 7 weeks, and 82–100% for 13 weeks post‐treatment, respectively. In used tyres, the same concentration of the repellents resulted in 100% reduction of Ae. albopictus larvae for 2 weeks (deet), 4 weeks (AI3‐35765) and 5 weeks (AI3‐37220) post‐treatment. In cemetery flower vases, Aedes spp. larvae were eliminated for 4 weeks (deet) and 6 weeks post‐treatment by both AI3‐35765 and AI3‐37220. These topical repellents (particularly AI3‐37220) have good potential for development and use in the management of container‐inhabiting mosquitoes because they deter oviposition and kill larvae.
Visual and olfactory cue interaction in resource‐location by the blowfly, Lucilia sericata
Authors: Wall Richard , Fisher Paul
Published: March 2003

Abstract. The interactions between olfactory and visual cues in the landing responses of the blowfly Lucilia sericata (Meigen) (Diptera: Calliphoridae) were examined in a laboratory wind tunnel. The odour of liver and sodium sulphide solution released at 1 L/min, resulted in a greater number of landings, closer to, but downwind of, the central odour release point, than when odour was absent. Three‐day‐old protein‐deprived females landed in greater numbers than protein‐fed female flies of the same age; no difference existed between 6‐day‐old protein‐fed or protein‐deprived females. Six‐day‐old, protein‐fed flies landed closer to the odour source than did 3‐day‐old, protein‐fed flies. In the presence of odour, flies landed closer to the central release point when it was accompanied by a visual cue. No such effect of the visual cue was evident in the absence of odour. When a plain white sticky‐surface (25 × 25 cm) was paired with an identical white surface plus odour, approximately equal numbers of flies landed when the surfaces were placed together; increasingly higher numbers of flies landed on the surface with the odour cue when the distance between the surfaces was increased. When a white surface with a visual cue was presented with the plain white surface plus odour, more flies landed on the white surface with the visual cue than on the plain white surface with odour when they were close together. However, as these two surfaces were moved apart, flies landed increasingly more on the surface with the odour than the surface with the visual cue. The results show that while odour cues may enhance the induction of landing by female L. sericata, visual cues are important when selecting a final landing site.
Initial characterization of the Streptococcus gordonii htpX gene
Authors: Vickerman M. M. , Mather N. M. , Minick P. E. , Edwards C. A.
Published: March 2003

Examination of the Streptococcus gordonii chromosomal region, which lies immediately upstream of the glucosyltransferase positive regulatory determinant rgg, revealed two open reading frames. Based on nucleotide sequences, these genes were similar to the Listeria monocytogenes lemA gene, which is involved in antigen presentation, and the Escherichia coli htpX heat shock gene, which has an unknown function. Northern hybridization analysis indicated that S. gordonii lemA and htpX genes were associated with a ca. 1.7‐kb polycistronic transcript. Although levels of the lemA/htpX transcript did not increase in response to heat to levels seen with dnaK controls, insertional inactivation of htpX resulted in changes in adhesiveness, cellular morphology and detergent‐extractable surface antigens in cells grown at 41°C, implying that htpX may be involved in surface protein expression. Insertional inactivation of lemA and htpX indicated that, despite their proximity to rgg and the structural gene, gtfG, these upstream genes do not affect S. gordonii glucosyltransferase activity.
The transcriptional regulation of the Streptococcus mutans bgl regulon
Authors: Cote C. K. , Honeyman A. L.
Published: March 2003

A β‐glucoside utilization regulon recently isolated from Streptococcus mutans has been shown to contain genes involved in β‐glucoside hydrolysis and a putative regulator. The bglP gene encodes a β‐glucoside‐specific enzyme II (EII) component of the phosphoenolpyruvate‐dependent phosphotransferase system, the bglC gene encodes a putative transcriptional regulator, and the bglA gene encodes a putative phospho‐β‐glucosidase. To investigate the transcriptional activity of these genes, the putative promoter regions of the bglP, bglC and bglA genes were fused with the E. coli lacZ reporter gene. The resultant reporter plasmids were used to monitor the transcriptional activity of these loci in S. mutans. The results illustrate that these genes are not repressed by glucose in the presence of an inducing β‐glucoside, esculin, to the levels of expression observed in the absence of esculin. Therefore, these loci are not subject to catabolite repression by glucose to noninduced levels of expression. The bglC gene product was determined to be a positive transcriptional regulator of the bglA gene but does not regulate the expression of the bglP gene. Thus, regulation of these loci requires different and multiple control mechanisms.
Dipeptide utilization by the periodontal pathogens Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Fusobacterium nucleatum
Authors: Takahashi N. , Sato T.
Published: March 2003

Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Fusobacterium nucleatum, which can frequently be isolated from periodontal pockets, preferentially utilize proteins and peptides as growth substrates. In this study, we determined the size of peptide that is preferentially utilized as a source of energy and material for cell growth by P. gingivalis, P. intermedia, P. nigrescens and F. nucleatum using various sizes of poly amino acids consisting of two to approximately 100 molecules of aspartate or glutamate. Resting cells of P. gingivalis, P. intermedia and P. nigrescens utilized aspartylaspartate, while cells of P. gingivalis and F. nucleatum utilized glutamylglutamate. The addition of aspartylaspartate to the culture medium increased the growth of P. gingivalis, P. intermedia and P. nigrescens, while the addition of glutamylglutamate promoted the growth of P. gingivalis and F. nucleatum. These results clearly indicate that dipeptides such as aspartylaspartate and glutamylglutamate can be utilized as growth substrates for P. gingivalis, P. intermedia, P. nigrescens and F. nucleatum.
Differences in Candida albicans adhesion to intact and denatured type I collagen in vitro
Authors: Makihira S. , Nikawa H. , Tamagami M. , Hamada T. , Samaranayake L. P.
Published: March 2003

An inhibition assay of Candida albicans adhesion to gelatin‐immobilized membranes was compared with that to intact type I collagen‐immobilized membranes using an arginine‐glycine‐aspartic acid (RGD) containing peptide. As compared with a protein‐free membrane, gelatin and collagen significantly enhanced the adherence of C. albicans. The adhesion of the yeast to gelatin was significantly inhibited by the RGD peptides, but not by arginine‐glycine‐glutamic acid (RGE) peptides. In contrast, attachment to collagen was not inhibited by RGD peptides. These results suggest that the RGD sequence of gelatin and the integrin‐like proteins of yeasts may be involved in adherence.
Demonstration and distribution of tau‐positive glial coiled body‐like structures in white matter and white matter threads in early onset Alzheimer’s disease
Authors: Umahara Takahiko , Tsuchiya Kuniaki , Ikeda Kenzi , Kanaya Kiyoshi , Iwamoto Toshihiko , Takasaki Masharu , Mukai Kiyoshi , Shibata Noriyuki , Kato Shinsuke
Published: March 2003

The present report concerns the demonstration and distribution of tau‐positive structures in the frontal and temporal white matter of five autopsy cases of early onset Alzheimer’s disease (AD). The relationship between white matter lesions and tau positive structures was also investigated. Five early onset AD brains, which had not only unambiguous white matter lesions, but also no or rare atherosclerosis and minimal amyloid angiopathy, were examined. There were several tau‐positive coiled body‐like structures and many thread‐like structures in the white matter, although previous reports showed only a few coiled bodies in the white matter in the AD brain. No relationship was found between the degree of each white matter lesion and number or distribution of tau‐positive structures in the white matter. The results suggest that the AD brain has tau‐positive structures in the white matter similar to some neurodegenarative brain diseases such as progressive supranuclear palsy, corticobasal degeneration, and dementia with grains. However, tau abnormalities may have fewer effects when they are located in white matter lesions in AD.
Technical Advance: Tobacco rattle virus as a vector for analysis of gene function by silencing
Authors: Ratcliff Frank , Martin‐Hernandez Ana Montserrat , Baulcombe David C.
Published: March 2003

Virus vectors carrying host‐derived sequence inserts induce silencing of the corresponding genes in infected plants. This virus‐induced gene silencing (VIGS) is a manifestation of an RNA‐mediated defence mechanism that is related to post‐transcriptional gene silencing (PTGS) in transgenic plants. Here we describe an infectious cDNA clone of tobacco rattle virus (TRV) that has been modified to facilitate insertion of non‐viral sequence and subsequent infection to plants. We show that this vector mediates VIGS of endogenous genes in the absence of virus‐induced symptoms. Unlike other RNA virus vectors that have been used previously for VIGS, the TRV construct is able to target host RNAs in the growing points of plants. These features indicate that the TRV vector will have wide application for gene discovery in plants.
Two distinct high‐affinity sulfate transporters with different inducibilities mediate uptake of sulfate in Arabidopsis roots
Authors: Yoshimoto Naoko , Takahashi Hideki , Smith Frank W. , Yamaya Tomoyuki , Saito Kazuki
Published: March 2003

Sulfate transporters present at the root surface facilitate uptake of sulfate from the environment. Here we report that uptake of sulfate at the outermost cell layers of Arabidopsis root is associated with the functions of highly and low‐inducible sulfate transporters, Sultr1;1 and Sultr1;2, respectively. We have previously reported that Sultr1;1 is a high‐affinity sulfate transporter expressed in root hairs, epidermal and cortical cells of Arabidopsis roots, and its expression is strongly upregulated in plants deprived of external sulfate. A novel sulfate transporter gene, Sultr1;2, identified on the BAC clone F28K19 of Arabidopsis, encoded a polypeptide of 653 amino acids that is 72.6% identical to Sultr1;1 and was able to restore sulfate uptake capacity of a yeast mutant lacking sulfate transporter genes (Km for sulfate = 6.9 ± 1.0 µm). Transgenic Arabidopsis plants expressing the fusion gene construct of the Sultr1;2 promoter and green fluorescent protein (GFP) showed specific localization of GFP in the root hairs, epidermal and cortical cells of roots, and in the guard cells of leaves, suggesting that Sultr1;2 may co‐localize with Sultr1;1 in the same cell layers at the root surface. Sultr1;1 mRNA was abundantly expressed under low‐sulfur conditions (50–100 µm sulfate), whereas Sultr1;2 mRNA accumulated constitutively at high levels under a wide range of sulfur conditions (50–1500 µm sulfate), indicating that Sultr1;2 is less responsive to changes in sulfur conditions. Addition of selenate to the medium increased the level of Sultr1;1 mRNA in parallel with a decrease in the internal sulfate pool in roots. The level of Sultr1;2 mRNA was not influenced under these conditions. Antisense plants of Sultr1;1 showed reduced accumulation of sulfate in roots, particularly in plants treated with selenate, suggesting that the inducible transporter Sultr1;1 contributes to the uptake of sulfate under stressed conditions.
Bilateral connation of permanent mandibular incisors: a case report
Authors: Neves A. A. , Neves M. L. A. , Farinhas J. A.
Published: March 2003

Summary.  Connated teeth are the consequences of developmental anomalies leading to the eruption of joined elements. According to current definitions, gemination occurs when one tooth bud tries to divide, while fusion occurs if two buds unite. Clinical experience shows, however, that diagnosis can be complicated due to superimposed anomalies. This report describes a unique case of bilateral fusion of permanent mandibular incisors and discusses the differential diagnosis and possible future treatment options anticipated for this particular case.
Assessment of Fallopian tube patency by HyCoSy: comparison of a positive contrast agent with saline solution
Authors: Boudghène F. P. , Bazot M. , Robert Y. , Perrot N. , Rocourt N. , Antoine J.‐M. , Morris H. , Leroy J.‐L. , Uzan S. , Bigot J.‐M.
Published: March 2003

Objective

To compare the efficiency of air‐filled albumin microspheres (Infoson) with saline solution in determining Fallopian tube patency during hysterosalpingo contrast sonography (HyCoSy).

Methods

This was a prospective randomized multicenter study with a sequential design. Over a 10‐month period, 23 patients (mean age, 33 years) referred for infertility were examined by HyCoSy (saline or Infoson) before conventional hysterosalpingography (Iopamiron® 370), performed during the same session. Contrast agents were administered through a 5‐F Ackrad balloon catheter inserted transcervically into the uterine cavity. HyCoSy was performed with a 7‐MHz transvaginal probe using both B‐mode and color Doppler, and tubal patency was demonstrated by the appearance of contrast agent in the peritoneal cavity near the ovaries. Data were registered for each patient during the examination and the results were monitored by sequential analysis.

Results

Mean volumes of contrast injections were 35.3 mL of saline, 14.4 mL of Infoson, and 13.8 mL of Iopamiron 370. Infoson‐enhanced HyCoSy provided a significantly larger (P = 0.006) number of correct diagnoses (20/22 Fallopian tubes) than did saline HyCoSy (12/24 Fallopian tubes), and the same number as that achieved by hysterosalpingography.

Conclusion

A positive ultrasound contrast agent appears to be more efficient than saline solution at determining Fallopian tube patency in infertile women by means of HyCoSy, and as efficient as an iodinated contrast agent in the same population explored by HSG. HyCoSy could be used to screen infertile women, thereby avoiding the use of iodinated contrast medium and exposure to ionizing radiation during conventional HSG in patients with patent Fallopian tubes. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology
Impaired uteroplacental blood flow in pregnancies complicated by falciparum malaria
Authors: Dorman E. K. , Shulman C. E. , Kingdom J. , Bulmer J. N. , Mwendwa J. , Peshu N. , Marsh K.
Published: March 2003

Objective

In endemic areas, maternal malaria infection is usually asymptomatic. However, it is known that infected maternal erythrocytes sequester in the intervillous space of the placenta. There is a strong association between placental malaria infection and both low birth weight (LBW) and severe maternal anemia. We aimed to determine whether impaired uteroplacental blood flow might account for the low infant birth weight associated with maternal falciparum malaria infection.

Methods

This observational study was carried out during a large double‐blind, randomized, controlled trial of an antimalarial drug intervention for primigravidae. Nine hundred and ninety‐five women were recruited from the antenatal clinic at a district hospital on the Kenya coast and had at least one Doppler ultrasound scan. Uterine artery resistance index and the presence or absence of a diastolic notch were recorded. In the third trimester, blood was taken for hemoglobin and malaria film.

Results

Malaria infection at 32–35 weeks of gestation was associated with abnormal uterine artery flow velocity waveforms on the day of blood testing (relative risk (RR) 2.11, 95% confidence interval (CI) 1.24–3.59, P = 0.006). This association persisted after controlling for pre‐eclampsia. Impaired uteroplacental blood flow in the women studied was also predictive of poor perinatal outcome, including low birth weight, preterm delivery and perinatal death. The risk of preterm delivery in women with histological evidence of past placental malaria infection was more than twice that of women without infection (RR 2.33, 95% CI 1.31–4.13, P = 0.004).

Conclusions

Uteroplacental hemodynamics are altered in the presence of maternal falciparum malaria infection. This may account for some of the excess of LBW babies observed in malaria endemic areas. Strategies that prevent or clear placental malaria may confer perinatal benefit through preservation of placental function. Copyright © 2002 ISUOG
Routine ultrasound screening in diabetic pregnancies
Authors: Wong S. F. , Chan F. Y. , Cincotta R. B. , Oats J. J. N. , Mcintyre H. D.
Published: March 2003

Objectives

To assess the detection rate of congenital fetal malformations and specific problems related to routine ultrasound screening in women with pre‐existing diabetes.

Methods

A retrospective study was carried out to assess the performance of routine ultrasound screening in women with pre‐existing diabetes (Types 1 and 2) within a tertiary institution. The incidence, type and risk factors for congenital fetal malformations were determined. The detection rate of fetal anomalies for diabetic women was compared with that for the low‐risk population. Factors affecting these detection rates were evaluated.

Results

During the study period, 12 169 low‐risk pregnant women and 130 women with pre‐existing diabetes had routine ultrasound screening performed within the institution. A total of 10 major anomalies (7.7%) and three minor anomalies (2.3%) were present in the fetuses of the diabetic women. Central nervous system and cardiovascular system anomalies accounted for 60% of the major anomalies. Periconceptional hemoglobin A1c of more than 9% was associated with a high prevalence of major anomalies (143/1000). Women who had fetuses with major anomalies had a significantly higher incidence of obesity (78% vs. 37%; P < 0.05). Ultrasound examination of these diabetic pregnancies showed high incidences of suboptimal image quality (37%), incomplete examinations, and repeat examinations (17%). Compared to the ‘low‐risk’ non‐diabetic population from the same institution, the relative risk for a major congenital anomaly among the diabetic women was 5.9‐fold higher (95% confidence interval, 2.9–11.9). The detection rate for major fetal anomalies was significantly lower for diabetic women (30% vs. 73%; P < 0.01), and the mean body mass index for the diabetic group was significantly higher (29 vs. 23 kg/m2; P < 0.001).

Conclusion

The incidence of congenital anomalies is higher in diabetic pregnancies. Unfortunately, the detection rate for fetal anomalies by antenatal ultrasound scan was significantly worse than that for the low‐risk population. This is likely to be related to the maternal body habitus and unsatisfactory examinations. Methods to overcome these difficulties are discussed. Copyright © 2002 ISUOG
Right and left ventricular long‐axis function in the fetus using angular M‐mode
Authors: Carvalho J. S. , O'Sullivan C. , Shinebourne E. A. , Henein M. Y.
Published: March 2003

Objective

Long‐axis function is determined by the longitudinally oriented myocardial fibers. Postnatally, conventional M‐mode is used to assess tricuspid and mitral valve ring movements in relation to the cardiac apex. During fetal life, this is precluded by variable fetal position. We assessed the feasibility of determining right and left ventricular long‐axis function in the fetus.

Methods

A prospective, pilot study. The four‐chamber view obtained during routine fetal echocardiography was recorded in a cineloop to which B‐mode guided M‐mode echocardiography was applied using angular M‐mode. This allowed retrospective and correct placement of the cursor line from cardiac apex to tricuspid or mitral valve rings. M‐mode tracings of the valve ring movements in relation to the apex were derived from the originally stored loop. Data from 18 fetuses (17–29 weeks of gestation) were available for analysis. Total excursion of the valve rings was measured offline. A second cursor line was simultaneously placed in the left ventricular outflow tract during color flow mapping for timing purposes (n = 6).

Results

Right and left ventricular long‐axis recordings were obtained in 18 and 14 cases, respectively. Total right ventricular excursion was 5.2 mm (SD, 0.9 mm) (range, 3.9–7.2 mm). Total left ventricular free wall excursion was 4.5 mm (SD, 1.1 mm) (range, 3.0–6.8 mm). For paired data, the mean of differences (right ventricle – left ventricle) was 0.8 mm (95% confidence interval 0.5–1.2). The valve rings moved towards the apex during systole (shortening) and away from it during diastole (lengthening). Peak downward movement coincided with cessation of aortic flow and diastolic lengthening with flow through the atrioventricular valves.

Conclusion

Long‐axis function in the fetus is feasible if M‐mode angle correction is used. There was no clinically significant difference between tricuspid and mitral valve excursions. The pattern of atrioventricular valve movement is coordinate and similar to that of adults. Long‐axis function offers a new avenue to study systolic and diastolic function in the fetus.Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecology
Regulation of midgut defensin production in the blood‐sucking insect Stomoxys calcitrans
Authors: Munks R. J. L. , Hamilton J. V. , Lehane S. M. , Lehane M. J.
Published: March 2003

The Stomoxys midgut defensin (Smd) family of genes are exclusively expressed in the anterior midgut of adult flies. Their putative function is protection of the stored bloodmeal from microbial attack. Smd genes are constitutively expressed, up‐regulated in response to a bloodmeal and further up‐regulated by immune stimulation per os but only in the presence of a bloodmeal not a sugar meal. Smd genes are down‐regulated in response to a systemic immune challenge. Smd gene constructs transfected into l(2)mbn cells undertake constitutive expression but are not up‐regulated by immune challenge. Electrophoretic mobility shift assays (EMSA) suggest the rel‐like sites in the proximal promoter region of Smd genes do not bind midgut factors and so are non‐functional.
Overproduction of a P450 that metabolizes diazinon is linked to a loss‐of‐function in the chromosome 2 ali‐esterase (MdαE7) gene in resistant house flies
Authors: Sabourault C. , Guzov V. M. , Koener J. F. , Claudianos C. , Plapp F. W. , Feyereisen R.
Published: March 2003

Up‐regulation of detoxifying enzymes in insecticide‐resistant strains of the house fly is a common mechanism for metabolic resistance. However, the molecular basis of this increased insecticide metabolism is not well understood. In the multiresistant Rutgers strain, several cytochromes P450 and glutathione S‐transferases are constitutively overexpressed at the transcriptional level. Overexpression is the result of trans‐regulation, and a regulatory gene has been located on chromosome 2. A Gly137 to Asp point mutation in αE7 esterase gene, leading to the loss of carboxylesterase activity, has been associated with organophosphate resistance in the house fly and the sheep blowfly. We show here that purified recombinant CYP6A1 is able to detoxify diazinon with a high efficiency. We also show that either the Gly137 to Asp point mutation in αE7 esterase gene or a deletion at this locus confer resistance and overproduction of the CYP6A1 protein. Based on these findings, we propose it is the absence of the wild‐type Gly137 allele of the αE7 gene that releases the transcriptional repression of genes coding for detoxification enzymes such as CYP6A1, thereby leading to metabolic resistance to diazinon.
Identification and characterization of a Drosophila homologue of ATBP
Authors: Aozasa N. , Kubo Takeo , Sekimizu Kazuhisa , Natori Shunji
Published: March 2003

ATBP [(A+T)‐stretch binding protein] activates the Sarcophaga defense protein genes in an (A+T)‐stretch dependent manner as shown previously using a luciferase reporter assay [Aozasa et al. (2001) Eur J Biochem, 268, 2506–2511]. We identified the Drosophila homologue of ATBP. Drosophila ATBP has 388 amino acid residues and the amino acid sequence has high similarity with that of the Sarcophaga ATBP. In particular, residues 1–56 and 301–374 are highly conserved between Sarcophaga and Drosophila. Drosophila ATBP activated the Sarcophaga lectin gene promoter in SL‐2 cells. The Drosophila ATBP gene is a single copy gene and is located in the 20E region of chromosome X.
Identification of fat‐cell enhancer regions in Drosophila melanogaster
Authors: Miller J. M. , Oligino T. , Pazdera M. , López A. J. , Hoshizaki D. K.
Published: March 2003

The insect fat body is a dynamic tissue involved in maintaining homeostasis. It functions not only in energy storage and intermediary metabolism but also in detoxification, communication and the immune response. Some of these functions are confined to distinct groups of fat body cells. In Drosophila melanogaster, discrete precursor‐cell clusters populate the fat body [Hoshizaki, D.K., Blackburn, T., Price, C., Ghosh, M., Miles, K., Ragucci, M. and Sweis, R. (1994) Embryonic fat‐cell lineage in Drosophila melanogaster. Development 120: 2489–2499; Hoshizaki, D.K., Lunz, R., Ghosh, M. and Johnson, W. (1995) Identification of fat‐cell enhancer activity in Drosophila melanogaster using P‐element enhancer traps. Genome 38: 497–506; Riechmann, V., Rehorn, K.P., Reuter, R. and Leptin, M. (1998) The genetic control of the distinction between fat body and gonadal mesoderm in Drosophila. Development 125: 713–723]. Whether these clusters populate defined morphological regions or whether they represent the precursors to functionally similar groups of fat‐body cells has not been formally demonstrated. We have identified a 2.1 kb enhancer region from serpent (srp), a GATA transcription factor gene that is sufficient to induce fat‐cell formation. This enhancer region drives expression in specific groups of precursor‐cell clusters, which we show give rise to defined regions of the mature embryonic fat body. We present evidence that srp expression in different precursor fat cells is controlled by independent cis‐acting regulatory regions, and we have tested the role of trans‐acting factors in the specification of some of these cells. We suggest that the different positional cues regulating srp expression, and therefore general fat‐cell specification, might also be involved in the functional specialization of fat cells. This may be a common mechanism in insects to explain the origin of biochemically distinct regions of the larval/adult fat body.
Quantitative polymerase chain reaction analysis of DNA from noninvasive samples for accurate microsatellite genotyping of wild chimpanzees (Pan troglodytes verus)
Authors: Morin P. A. , Chambers K. E. , Boesch C. , Vigilant L.
Published: March 2003

Noninvasive samples are useful for molecular genetic analyses of wild animal populations. However, the low DNA content of such samples makes DNA amplification difficult, and there is the potential for erroneous results when one of two alleles at heterozygous microsatellite loci fails to be amplified. In this study we describe an assay designed to measure the amount of amplifiable nuclear DNA in low DNA concentration extracts from noninvasive samples. We describe the range of DNA amounts obtained from chimpanzee faeces and shed hair samples and formulate a new efficient approach for accurate microsatellite genotyping. Prescreening of extracts for DNA quantity is recommended for sorting of samples for likely success and reliability. Repetition of results remains extensive for analysis of microsatellite amplifications beginning from low starting amounts of DNA, but is reduced for those with higher DNA content.
Community analysis of arbuscular mycorrhizal fungi associated with Ammophila arenaria in Dutch coastal sand dunes
Authors: Kowalchuk George A. , De Souza Francisco A. , Van Veen Johannes A.
Published: March 2003

A polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE) approach for the detection and characterization of arbuscular mycorrhizal fungi (AMF) 18S ribosomal DNA (rDNA) was developed and applied to the study of AMF communities associated with the main sand‐stabilizing plant species of the Dutch sand dunes, marram grass (Ammophila arenaria, L.). DNA was extracted directly from plant roots, soil or isolated AMF spores, and prominent bands resulting from AMF‐specific DGGE profiles were excised for sequence analysis. This strategy provided a robust means of detecting and identifying AMF‐like species without the use of trap plant cultivation methods. A number of Glomus‐like and Scutellospora‐like sequences was detected, including a putatively novel Glomus species, and differences were observed in the dominant AMF‐like populations detected in healthy vs. degenerating stands of A. arenaria and in bulk sand dune soil. It has previously been suggested that plant pathogens, such as fungi and nematodes, may contribute to the decline of A. arenaria. Although no causal relationship can be drawn between the observed differences in the dominantly detected AMF‐like populations and the vitality of plant growth, these results indicate that mutualistic interactions between this plant and AMF should not be overlooked when examining the role of soil‐borne microorganisms in vegetation dynamics. In addition, there were discrepancies observed between the AMF‐like groups detected in spore populations vs. direct 18S rDNA analysis of root material, corroborating previous suggestions that spore inspection alone may poorly represent actual AMF population structure.