bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical analysis of a Ca2+‐dependent membrane–membrane interaction mediated by the sea urchin yolk granule protein, toposome
Authors: Hayley Michael , Perera Aruni , Robinson John J.
Published: July 2006

Toposome, a high molecular mass protein, is an abundant component of the yolk granule in the sea urchin egg and embryo. Toposome is composed of a 160 kDa polypeptide that is proteolytically processed into smaller species of 120 and 90 kDa during embryonic development. The exact biological function of toposome during early development is unknown. In this study we have examined calcium binding to toposome and the effect of this binding on the secondary and tertiary structural characteristics of the purified protein. Initially, we used equilibrium dialysis to quantify calcium binding to toposome. Monophasic binding of up to 600 M of calcium per mole of protein was detected with an intrinsic dissociation constant (calcium) of 240 µm. Increasing concentrations of calcium resulted in an increase in alpha helical content from 3.0 to 22.0%, which occurred with an apparent dissociation constant (calcium) of 25 µm. In parallel experiments, toposome binding to liposomes required similar concentrations of calcium; an apparent dissociation constant (calcium) of 25 µm was recorded. Endogenous tryptophan fluorescence measurements, both in the presence and absence of liposomes, demonstrated that the tertiary structure is sensitive to increasing concentrations of calcium with an apparent dissociation constant (calcium) of 240 µm. Toposome‐driven, liposome aggregation assays revealed a similar calcium requirement. Collectively, these results define a two‐step model for calcium modulation of toposome structure and function.
Isolation of planarian X‐ray‐sensitive stem cells by fluorescence‐activated cell sorting
Authors: Hayashi Tetsutaro , Asami Maki , Higuchi Sayaka , Shibata Norito , Agata Kiyokazu
Published: July 2006

The remarkable capability of planarian regeneration is mediated by a group of adult stem cells referred to as neoblasts. Although these cells possess many unique cytological characteristics (e.g. they are X‐ray sensitive and contain chromatoid bodies), it has been difficult to isolate them after cell dissociation. This is one of the major reasons why planarian regenerative mechanisms have remained elusive for a long time. Here, we describe a new method to isolate the planarian adult stem cells as X‐ray‐sensitive cell populations by fluorescence‐activated cell sorting (FACS). Dissociated cells from whole planarians were labeled with fluorescent dyes prior to fractionation by FACS. We compared the FACS profiles from X‐ray‐irradiated and non‐irradiated planarians, and thereby found two cell fractions which contained X‐ray‐sensitive cells. These fractions, designated X1 and X2, were subjected to electron microscopic morphological analysis. We concluded that X‐ray‐sensitive cells in both fractions possessed typical stem cell morphology: an ovoid shape with a large nucleus and scant cytoplasm, and chromatoid bodies in the cytoplasm. This method of isolating X‐ray‐sensitive cells using FACS may provide a key tool for advancing our understanding of the stem cell system in planarians.
Effects of U0126 and fibroblast growth factor on gene expression profile in Ciona intestinalis embryos as revealed by microarray analysis
Authors: Sakabe Eriko , Tanaka Nobuhiko , Shimozono Naoki , Gojobori Takashi , Fujiwara Shigeki
Published: July 2006

Fibroblast growth factor (FGF) induces the notochord and mesenchyme in ascidian embryos, via extracellular signal‐regulated kinase (ERK) that belongs to the mitogen‐activated protein kinase (MAPK) family. A cDNA microarray analysis was carried out to identify genes affected by an inhibitor of MAPK/ERK kinase (MEK), U0126, in embryos of the ascidian Ciona intestinalis. Data obtained from the microarray and in situ hybridization suggest that the majority of genes are downregulated by U0126 treatment. Genes that were downregulated in U0126‐treated embryos included Ci‐Bra and Ci‐Twist‐like1 that are master regulatory genes of notochord and mesenchyme differentiation, respectively. The plasminogen mRNA was downregulated by U0126 in presumptive endoderm cells. This suggests that a MEK‐mediated extracellular signal is necessary for gene expression in tissues whose specification does not depend on cell‐to‐cell interaction. Among 85 cDNA clusters that were not affected by U0126, 30 showed mitochondria‐like mRNA localization in the nerve cord/muscle lineage blastomeres in the equatorial region. The expression level and asymmetric distribution of these mRNA were independent of MEK signaling.
New Zealand cataract and refractive surgery survey 2004
Authors: Elder Mark , Leaming David , Hoy Benjamin
Published: July 2006

Abstract

Background:  This study examines the current practice and trends for cataract and refractive surgery in New Zealand.

Methods:  A confidential postal questionnaire was sent to all consultant ophthalmologists practising in New Zealand in 2004. Most questions were identical to the 2000 New Zealand survey, and were also similar to the 2003 survey of the American Society of Cataract and Refraction Surgeons (ASCRS).

Results:  From 97 surveys there was a 92% response rate. Of those surveyed, 70 were performing cataract surgery, 17 were performing refractive surgery, subtenons anaesthetic was used for cataract surgery in 60%, clear corneal or anterior limbal incision in 86%, one‐piece foldable intraocular lens in 65%. For refractive surgery, use of refractive lens surgery was recommended for high refractive errors. Advice to a 45‐year‐old +3.00 hypermetrope wanting refractive surgery was to have laser in situ keratomileusis (88%), laser epithelial keratomileusis (6%) or clear lens extraction (6%). Ninety‐four per cent of refractive surgeons in New Zealand used a wavefront analyser. Clear lens extraction was practised by 23 ophthalmologists, phakic intraocular lenses by 16 ophthalmologists.

Discussion:  New Zealand cataract and refractive surgery practice remains comparable to that of the members of the ASCRS. As in previous comparisons, there is a relatively low use of topical anaesthetic (New Zealand 19%vs. USA 61%vs. UK [pilot study] 33.3%). This survey showed a high uptake of wavefront analysis in refractive surgery (New Zealand 94%vs. USA 45%).
Evaluation of the effects of hydrodissection with antimitotics using a rabbit model of Soemmering’s ring formation
Authors: Chew Jesse , Werner Liliana , Stevens Scott , Hunter Brian , Mamalis Nick
Published: July 2006

Abstract

Background:  Regeneration/proliferation of lens material within the capsular bag still is the most frequent complication after cataract surgery. We aimed to evaluate the effects of hydrodissection with low doses of antimitotics on the overall regeneration/proliferation of lens material in rabbit eyes, using a model allowing the lens material to be confined to the equatorial region of the capsular bag, facilitating its quantification.

Methods:  Twelve albino rabbits underwent bilateral phacoemulsification. Their eyes were randomized to receive 0.4 cc of balanced salt solution, 5‐fluorouracil (12.5 mg/mL) or mitomycin C (0.1 mg/mL) during hydrodissection. They were left aphakic, so the capsulorhexis would fuse with the posterior capsule postoperatively. After 4 weeks, killing/enucleation was performed. Regeneration/proliferation of lens material within the equatorial capsular bag (Soemmering’s ring) was graded from the Miyake–Apple view (0–4). Its area was also calculated (µm2) from direct measurements performed on histological sections.

Results:  The capsulorhexis margin fused with the peripheral posterior capsule, so the central posterior capsule remained clear. There was no significant difference among the groups (Kruskal–Wallis test) regarding Soemmering’s ring gross grading (P = 0.511), number of lens epithelial cell layers lining the inner surface of the capsular bag (P = 0.310) and Soemmering’s ring microscopic cross‐sectional area (P = 0.638).

Conclusions:  The effect of different solutions on after‐cataract should be assessed in terms of overall regeneration/proliferation of lens material within the capsular bag, in addition to posterior capsule opacification. When administered in low doses during hydrodissection, 5‐fluorouracil and mitomycin C did not show a significant inhibitory effect on after‐cataract formation in rabbit eyes.
Microcirculation at optic disc rim is correlated with visual field defects in cases of anterior ischaemic optic neuropathy
Authors: Yokoyama Shinsuke , Kimura Itaru , Ohde Hisao , Shinoda Kei , Mashima Yukihiko
Published: July 2006

Abstract

We report two cases of anterior ischaemic optic neuropathy in whom tissue blood flow at the disc rim was correlated with the visual field defect. Tissue blood flow of each eye was evaluated with Heidelberg retina flowmeter. Both cases experienced acute visual loss and an altitudinal hemianopsia associated with optic disc oedema in the affected eye. In each case, the tissue blood flow at the affected (upper or lower half) disc rim corresponding to visual field deficit was reduced compared with that at the opposite‐sided half disc rim in the affected eye and with the corresponding area in the fellow eye. The reduction of blood flow in the affected half disc rim associated with the visual field defect demonstrated that retina flowmetry can detect differences in tissue blood flow between superior and inferior sectional disc rim areas as well as between eyes non‐invasively.
Concordant bilateral Duane’s Retraction Syndrome (type 1) in female monozygotic twins
Authors: Dirani Mohamed , Chamberlain Matthew , Garoufalis Pam , Chen Christine , Guymer Robyn H , Baird Paul N
Published: July 2006

Abstract

We report a single case study of concordant bilateral Duane’s Retraction Syndrome (DRS) (type 1) in female monozygotic (MZ) twins aged 47 years. The twin pair were recruited through the Australian Twin Registry as part of a twin study on myopia. This twin pair were full term and had a similar birth weight: 2.27 kg and 1.81 kg in twin 1 and twin 2, respectively. There was no report of any other childhood medical conditions in either twin. Both twins had an equal amount of restriction in right and left abduction. Narrowing of the palpebral fissures and globe retraction in right and left adduction was also observed in both twins. To our knowledge this is the first case to report concordant bilateral DRS (type 1) in female MZ twins. The concordance for the presence of DRS and associated clinical signs observed in this MZ twin pair supports a genetic origin to DRS.
Characterization of fretting fatigue in self‐piercing riveted aluminium alloy sheets
Authors: HAN L. , CHRYSANTHOU A. , YOUNG K. W. , O'SULLIVAN J. M.
Published: July 2006

A study was conducted to characterize fretting fatigue in self‐piercing riveted single‐lap joints of aluminium alloy 5754 sheets. The experimental results showed that fretting occurred at three different positions in the joint. It was established that fretting led to surface work‐hardening and crack initiation as well as early stage crack propagation. Crack initiated at the surface of the riveted sheets as a result of high stress concentration and propagated oblique to the mating surface under the effect of fretting fatigue. The depth of damage due to fretting depended on the applied load and the cycle time. Microhardness measurements allowed the estimation of the depth of damage due to fretting. These results were observed to correlate well with the length of crack propagation.
A store‐operated current (SOC) mediates oxytocin autocontrol in the developing rat hypothalamus
Authors: Tobin Vicky , Gouty Laurie‐Anne , Moos Françoise C. , Desarménien Michel G.
Published: July 2006

Oxytocin (OT) and vasopressin (VP) autocontrol their secreting neurons in the supraoptic nucleus (SON) by modulating action potential firing through activation of specific metabotropic receptors. However, the mechanisms linking receptor activation to firing remain unknown. In almost all cell types, activation of plasma membrane metabotropic receptors triggers signalling cascades that induce mobilization of calcium from intracellular stores. In turn, emptying the calcium stores may evoke calcium influx through store‐operated channels (SOCs), the functions of which remain largely unknown in neurons. In this study, we show that these channels play a key role in the SON, at least in the response to OT. In isolated rat SON neurons, store depletion by thapsigargin induced an influx of calcium, demonstrating the presence of SOCs in these neurons. This calcium influx was specifically inhibited by 0.2 mm 1‐(2‐trifluoromethylphenyl‐)imidazole (TRIM). At 2 mm, this compound affected neither the resting electrophysiological properties nor the voltage‐dependant inward currents. In fresh slices, TRIM (2 mm) did not affect the resting potential of SON neurons, action potential characteristics, spontaneous action potential firing or synaptic activity; this compound thus appears to be a specific blocker of SOCs in SON neurons. TRIM (0.2 mm) specifically reduced the increase in action potential firing triggered by OT but did not affect the VP‐induced response. These observations demonstrate that store operated channels exist in hypothalamic neurons and specifically mediate the response to OT in the SON.
Role of the Preliminary Susceptibility Testing for Initial and After Failed Therapy of Helicobacter pylori Infection with Levofloxacin, Amoxicillin, and Esomeprazole
Authors: Marzio Leonardo , Coraggio Daniela , Capodicasa Simona , Grossi Laurino , Cappello Giorgio
Published: July 2006

Background:  Levofloxacin has been proposed as an alternative to classic therapy in secondary resistance to Helicobacter pylori.

Aim:  To evaluate primary and secondary resistance of H. pylori to levofloxacin, and to test the role of susceptibility test on the efficacy of levofloxacin‐based triple therapy.

Methods:  Eighty consecutive dyspeptic patients with positive 13C‐urea breath test never treated were randomly allocated into group A1 (40 patients) and group B1 (39 patients). Eighty‐three patients already treated unsuccessfully with positive 13C‐urea breath test were divided into group A2 (51 patients) and group B2 (32 patients). Patients in group A1 and group A2 underwent upper gastrointestinal endoscopy for H. pylori susceptibility test to amoxicillin, clarithromycin, tinidazole, rifabutin, and levofloxacin. These patients were treated with levofloxacin (500 mg b.i.d.), amoxicillin (1 g b.i.d.) and esomeprazole (20 mg b.i.d.) for 10 days if sensitive to these two antibiotics. If H. pylori was found resistant to amoxicillin and/or levofloxacin the treatment was based on the indications of the susceptibility test. Patients in group B1 and group B2 were treated empirically with levofloxacin, amoxicillin, and esomeprazole at the same dose and duration as group A. All patients underwent 13C‐urea breath test 2 months after the end of therapy.

Results:  The antibiotic resistance of H. pylori strains in group A1 and group A2 was (%): amoxicillin: 2.4, 10; clarithromycin: 21.9, 43.1; tinidazole: 31.7, 70; rifabutin: 2.4, 4; and levofloxacin: 9.7, 12.2, respectively. In group A1 with susceptibility test‐driven therapy, eradication was 97.2%, and in group B1 with empirical treatment, 94.1% (n.s.). In group A2 with susceptibility test, eradication was 97.5%, whereas in group B2 with empirical treatment 81.2% (p < .01).

Conclusion:  Primary and secondary resistance of H. pylori to levofloxacin is approximately 10% of the tested strains. The susceptibility test does not influence therapeutic outcome of triple therapy with amoxicillin and levofloxacin in patients never treated, while it is determinant for patients who were previously treated without success.
Bioinformatic Analysis of Helicobacter pylori XGPRTase: A Potential Therapeutic Target
Authors: Duckworth Megan , Ménard Armelle , Megraud Francis , Mendz George L.
Published: July 2006

Background:  Xanthine–guanine phosphoribosyltransferase (XGPRTase) is an enzyme of purine nucleotide salvage synthesis. The gpt gene of Helicobacter pylori has been annotated as encoding an XGPRTase and proposed as essential for survival of the bacterium in vitro. The aims of this work were to investigate the structure of H. pylori XGPRTase and to compare the key features of the enzyme to other phosphoribosyltransferases employing computational, modelling, and bioinformatic tools.

Materials and Methods:  XGPRTase activity was measured in the cytosolic fraction of H. pylori by 31P‐nuclear magnetic resonance spectroscopy, and also in recombinant XGPRTase produced by a cell‐free expression system. Bioinformatics was employed to analyze the phylogeny of XGPRTase, and a structural model of the XGPRTase was built using threading techniques. The observed interactions of purine phosphoribosyltransferases with immucillin‐GP were used to study the theoretical interactions of H. pylori XGPRTase with this transition‐state analog.

Results:  It was demonstrated that the gpt gene of H. pylori encodes a functional XGPRTase enzyme. Analyses of the XGPRTase sequence showed that the enzyme is significantly divergent from equivalent mammalian enzymes. Modelling served to identify specific features of the enzyme and key residues involved in catalysis.

Conclusions:  The H. pylori XGPRTase is structurally similar to other phosphoribosyltransferase enzymes, but there were significant differences between the hood domain of H. pylori XGPRTase and other purine salvage phosphoribosyltransferases. Significant differences were found between the interactions of the H. pylori and human enzymes with a purine phosphoribosyltransferase inhibitor.
Antimicrobial Susceptibility of Helicobacter pylori Strains in a Random Adult Swedish Population
Authors: Storskrubb Tom , Aro Pertti , Ronkainen Jukka , Wreiber Karin , Nyhlin Henry , Bolling‐Sternevald Elisabeth , Talley Nicholas J. , Engstrand Lars , Agréus Lars
Published: July 2006

Background and Aim:  Antimicrobial resistance in Helicobacter pylori is a growing problem and has become an important factor leading to eradication failure. Information on antimicrobial susceptibility is important for selection of an optimum treatment regimen. The resistance rate in a random population has not been studied previously.

Methods:  A random Swedish population sample (n = 3000, age 20–81 years) was surveyed using a mailed validated questionnaire assessing gastrointestinal symptoms (response rate of 74%). One‐third of the responders was invited, in random order, and accepted an esophagogastroduodenoscopy with biopsies for H. pylori culture and histology. Subjects were not treated for their H. pylori infection but a minimum inhibitory concentration of metronidazole, clarithromycin, amoxicillin, and tetracycline for the H. pylori isolates (n = 333) was determined by agar dilution. Prescribed antibiotic in the area was recorded.

Results:  Irrespective of symptomatology, 16.2% of the isolated H. pylori strains were resistant to metronidazole, 1.5% to clarithromycin, 0% to amoxicillin, and 0.3% to tetracycline. The antibiotic consumption was low from an international perspective.

Conclusion:  The resistance to the antibiotics was lower than expected from patient sample studies, especially for clarithromycin, most probably due to a restrictive prescription policy in the area. Introduction of a test‐and‐treat strategy in Sweden would only marginally affect the usage of clarithromycin.
Stroke and Chest Pain in Young People With Migraine
Authors: Hoffmann Michael
Published: July 2006

Background.—Cerebrovascular and cardiovascular complications in migraineurs may be part of the migraine process and also consequent to triptan treatment

Aim.—To determine the frequency, subtypes and associations of migraine‐associated stroke and angina in young people (18–49 years).

Methods.—Patients were derived from a tertiary referral migraine and stroke registry. Migraine‐associated stroke was classified according to the four groups described by Welch and by the TOAST etiological stroke classification. A clinical description of angina during a migraine attack was required for the diagnosis of cardiac migraine without concomitant triptan or other vasoactive medications

Results.—Of the young patients with stroke (349/1316; 26.5%), there were 30 (30/349; 8.6%) who had migraine at the time of stroke when categorized by the Welch classification type II to IV (type II n = 5, type III n = 2, type IV n = 3). Comparison of type I (n = 20) versus types II–IV (n = 10) showed significant difference (P= .03). Topographically the lesions were distributed into the partial anterior circulation (n = 8) and posterior circulation (n = 2) (P= .04). Comparison of anterior and posterior circulation territories of infarction indicated significant difference (n = 26/30 and 4/30; P= .01). The stroke etiological subtypes included cardiogenic (n = 5), atherogenic (n = 15), other (n = 5), and unknown (n = 5), with none diagnosed with small‐vessel cerebrovascular disease. Traditional stroke mechanistic entities (cardiac and atherogenic) differed significantly in comparison to the other and unknown categories P= .05. Cardiovascular patients with angina during a migraine attack (n = 9/1040; 0.9%), included IHS subtypes; migraine without aura (n = 4), migraine with aura (n = 4), and complicated migraine (n = 1). One patient required cardiac catheterization on account of significant ECG changes, with documented, reversible vasospasm.

Conclusion.—(i) Migraine‐induced stroke remains controversial, with only two probable cases of type Welch III A+B in a large registry. (ii) Cardiac migraine may be a distinct entity requiring careful differentiation from triptan‐induced chest pain.
The effect of granular nematicide incorporation depth and potato planting depth on potatoes grown in land infested with the potato cyst nematodes Globodera rostochiensis and G. pallida
Authors: WOODS S R , HAYDOCK P P J
Published: July 2006

Field experiments at Harper Adams, Shropshire and Wisbech, Cambridgeshire investigated the effect of nematicide incorporation and seed tuber planting depth on the yield of the potato (Solamum tuberosum L.) cultivars Estima and Maris Piper and the population control of the potato cyst nematodes Globodera rostochiensis Woll. (Skarbilovich) and G. pallida (Stone). The nematicide fosthiazate was applied at 3 kg−1 ha and either not incorporated, or incorporated to 20 cm or 35 cm. Potatoes were mechanically planted to three depths; approximately 10 cm, 15 cm and 25 cm.

Incorporation to 20 cm with tubers planted at a depth of 10 cm or 15 cm, reduced root invasion compared with the other treatments. Incorporating nematicide to 20 cm also gave consistently higher ware yields and better nematode control than the other incorporation methods, which were not significantly different to the control. However, ware yield and nematode multiplication rate were not significantly affected by planting depth.
Physiological ageing of potato tubers: A Review
Authors: COLEMAN WARREN K
Published: July 2006

Numerous theories have been proposed to describe the complex process of ageing in biological systems. Two general groups of ageing theories currently exist: 1) stochastic where the accumulation of random molecular damage leads to loss of information vital to the cell; and, 2) systemic where an organised, genetically based sequence of metabolic activities leads to programmed ageing. Whether these are acceptable models of ageing in potato tubers is unknown although the tuber could provide a useful experimental system for studying ageing. An initial requirement for advancing the concept of ageing in potato tubers must centre on the development of a suitable ageing index. A review of the literature suggests that a modified approach to ‘sprouting capacity’ and ‘incubation period’ may allow tuber ageing to be described in mathematical terms that would, in turn, facilitate the development of a physiological ageing index as well as temperature sensitive predictive models. Although a number of biochemical studies of ageing have been pursued, the development of adequate biomarkers has yet to achieve a coordinated level of development as found in a range of organisms. For example, ageing in other biological systems may be viewed as an outcome of an accumulation of random molecular damage and may be primarily caused by a changing balance between reactive oxygen species and diminishing levels of protective agents such as superoxide dismutase, alpha‐tocopherol or vitamin C. The exploration of these and similar problems in the context of appropriate modelling approaches should allow a better understanding of physiological ageing in potato tubers.
Micropropagation of three berry fruit species using nodal segments from field‐grown plants
Authors: GONZALEZ M V , LOPEZ M , VALDES A E , ORDAS R J
Published: July 2006

Plant micropropagation of blueberry (Vaccinium corymbosum L. cv. Berkeley), blackberry (Rubus sp. cv. Smoothstem) and raspberry (Rubus idaeus L. cv. Gradina) was carried out from nodal segments of adult field‐grown plants. Hardwood and softwood cuttings were studied as explant sources. The cultures successfully established were softwood from all three species, and hardwood only from blueberry. Shoot‐bud establishment from blueberry was achieved by culturing explants in WPM salts with MS vitamins for 15 days, and then 30 days in the same medium with 18 mM Zeatin. The best results of multiplication were obtained in the same medium with 25 mM 2iP. For blackberry, shoot‐bud establishment was achieved by culturing explants in MS medium for 15 days, and then in the same medium with 4 mM BA and 0.25 mM IBA. This medium was also the best for blackberry multiplication. Raspberry explants (cvs Gradina and Willamette) were cultured in MS medium for 15 days and then transferred to MS medium supplemented with 4 μm BA and 0.25 mM IBA. After 30 days of culture, only ‘Gradina’ explants survived, from which shoot‐bud establishment was obtained in a modified MS medium (Anderson's macronutrients except calcium, with Sequestrene as the iron source) with the same growth regulators. Multiplication was achieved by subculturing explants in the same medium either with 4 mM BA plus 0.25 mM IBA or with 8 mM BA plus 0.25 mM IBA. Shoots of at least 1 cm in length from all species were rooted ex vitro in a mixture of peat and Perlite (1:1, v/v) in a mist chamber, and 100% of rooting plants were acclimated. Bacterial, fungal and viral diseases were detected in stock plants, while tests carried out in both shoots and regenerated plants revealed the absence of any kind of disease.
Effects of temperature on biology and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae)
Authors: LIU YING HONG , TSAI JAMES H
Published: July 2006

The development, survivorship, longevity, reproduction, and life table parameters of the Asian citrus psyllid, Diaphorina citri Kuwayama were evaluated at 10°C, 15°C, 20°C, 25°C, 28°C, 30°C and 33°C. The populations reared at 10°C and 33°C failed to develop. Between 15°C and 30°C, mean developmental period from egg to adult varied from 49.3 days at 15°C to 14.1 days at 28°C. The low‐temperature developmental thresholds for 1st through 5th instars were estimated at 11.7°C, 10.7°C, 10.1°C, 10.5°C and 10.9°C, respectively. A modified Logan model was used to describe the relationship between developmental rate and temperature. The survival of the 3rd through 5th nymphal instars at 15–28°C was essentially the same. The mean longevity of females increased with decreasing temperature within 15–30°C. The maximal longevity of individual females was recorded 117, 60, 56, 52 and 51 days at 15°C, 20°C, 25°C, 28°C and 30°C, respectively. The average number of eggs produced per female significantly increased with increasing temperature and reached a maximum of 748.3 eggs at 28°C (P<0.001). The population reared at 28°C had the highest intrinsic rate of increased (0.199) and net reproductive rate (292.2); and the shortest population doubling time (3.5 days) and mean generation time (28.6 days) compared with populations reared at 15–25°C. The optimum range of temperatures for D. citri population growth was 25–28°C.
Genetic variability of photosynthesis and water use in Balearic grapevine cultivars
Authors: BOTA By J , FLEXAS J , MEDRANO H
Published: July 2006

A comparison of photosynthetic characteristics of 20 cultivars of grapevine (Vitis vinifera L.) from Mallorca (Balearic Islands, Spain) and two widespread cultivars, Cabernet Sauvignon and Chardonnay, was made under irrigation as well as in response to drought. Although these cultivars share a common origin, a high variability was found for several photosynthetic characters under irrigation. Interestingly, these variations were significant for gas‐exchange parameters (net CO2 assimilation, stomatal conductance and intrinsic water use efficiency) but not for chlorophyll fluorescence parameters (maximum photochemical efficiency, electron transport rate and non‐photochemical quenching). Since water stress is the most limiting factor for plant production under the Mediterranean climate, it is presumable that these findings reflect specific selection pressures over physiological characteristics related to a balance between net carbon gain and water use. Some cultivars presented high carbon assimilation at the expense of a high water loss, whereas others were water savers, accompanied by low CO2 assimilation even under irrigation. Escursach was found to be an interesting cultivar, presenting low water consumption at the same time as reasonably high carbon assimilation. These cultivars also showed different responses to drought, which allowed their classification in two main groups: alarmist cultivars, which showed strong reductions of stomatal conductance in response to relatively low decreases of leaf water potential, and luxurious cultivars, showing low reductions of stomatal conductance under water stress.
Fluctuations in concentration of two potyviruses in garlic during the growing period and sampling conditions for reliable detection by ELISA
Authors: DOVAS C I , MAMOLOS A P , KATIS N I
Published: July 2006

To optimise sampling conditions for the detection by ELISA of Onion yellow dwarf virus (OYDV) and Leek yellow stripe virus (LYSV), the most important viral pathogens of garlic worldwide, relative virus concentrations were determined during the growing period and in different leaf parts by DAS‐ELISA. Both viruses were found to have uneven distributions in garlic plants, with the tips of the two latest fully developed leaves showing the highest concentrations and the oldest leaves the lowest concentrations. The tips of the youngest leaves were found to have higher virus concentrations than their middle and basal sections. In the older leaves, viruses were distributed more uniformly in the three leaf sections. In the oldest leaves virus levels in the leaf tips were significantly decreased. The concentrations of OYDV and LYSV increased until March, whereas later on they decreased. During storage of leaf samples at 6°C for 15 days, a loss was found of both virus antigens of more than 80%, and during 109 days of storage at −30°C a loss of more than 90% was found.
Stimulation of Armillaria mellea by phenolic fungicides
Authors: WEST JONATHAN S , FOX ROLAND T V
Published: July 2006

Phenolic fungicides, which were initially fungicidal to mycelium of Armillaria mellea on the surface of well‐colonised wood billets, eventually stimulated the growth of A. mellea. An extensive growth of rhizomorphs was produced from A. mellea inoculum, which had been exposed to phenolic chemicals for 3 months, compared to few or no rhizomorphs produced from inoculum exposed to water or a suspension of a non‐phenolic fungicide, fenpropidin. Inoculated privet plants grown either in pots or under field conditions were treated with a range of fungicides; fenpropidin, phenyl phenol, cresylic acid or water (control) was applied every 6 months over 21/2 yr. Fenpropidin caused a slightly (but significantly) lower incidence of infection than occurred in untreated plants, but the phenolic fungicides, cresylic acid and phenyl phenol, did not reduce the incidence of infection. The severity of infection (% root circumference colonised at 5 cm depth) was greater following cresylic acid treatments than the other fungicides or water‐treated controls. Use of phenolic fungicides such as cresylic acid for the control of A. mellea may therefore be counter‐productive.
Life history and phenology of the eucalyptus psyllid, Ctenarytaina eucalypti in Ireland
Authors: PURVIS GORDON , CHAUZAT MARIE‐PIERRE , SEGONDS‐PICHON ANNE , DUNNE RICHARD
Published: July 2006

During the early 1990s, the eucalyptus psyllid, Ctenarytaina eucalypti Maskell, was accidentally introduced into Ireland and began to threaten economically a newly developing ornamental foliage production industry based in the south west. The life cycle of the psyllid was studied at three field sites in Co. Kerry. The psyllid exhibited a complex seasonal population dynamic suggesting that two, largely overlapping population cohorts over‐winter as eggs and nymphs, respectively, in a state of reduced development or temporary dormancy. The duration of this dormancy is short. Evidence of a resumption of activity was monitored at all sites in early February with increasing adult numbers and renewed egg laying being seen before any significant rise in temperatures. This strongly suggests that retarded development, and resumption of psyllid activity in early spring, are at least partially consequences of the changing nutritional quality of the food plant, probably mediated by changing day length. As a consequence of seasonally inhibited development, individual egg and nymphal over‐wintering cohorts probably alternate in the completion of two or three generations per growing season. Analysis of psyllid numbers on shoot samples showed that greater population densities were found on shoots at the top of the food plant compared with lower‐placed shoots. Evidence was also found that the distribution of nymphal instars changed seasonally, probably in response to population density and increased competition for preferred feeding sites. Overall psyllid abundance, and the finer details of seasonal population dynamics, varied between plantations. In the absence of effective predation or parasitism by indigenous natural enemies, these differences were also likely to be due to variation in nutritional quality of the host plant and may be influenced by crop husbandry factors such as the timing and severity of crop pruning.
Physiological effects of peracetic acid on hydroponic tomato plants
Authors: VINES J R L , JENKINS P D , FOYER C H , FRENCH M S , SCOTT I M
Published: July 2006

Peracetic acid (PAA) has potential as a disinfectant of low environmental impact for glasshouse hydroponic systems and other horticultural applications, but can have phytotoxic effects. This study examined the physiological effects of PAA when applied hydroponically to tomato plants. Plants treated with 0.5–5 μg ml−1 PAA over several weeks exhibited a reduction in size of all vegetative organs. During the first 2 h of PAA treatment, plants also exhibited a transient wilting, with increased stomatal resistance, and reductions in transpiration and CO2 assimilation. The toxicity of PAA to roots was apparent from increased leakage of root electrolytes, reduced oxygen consumption, death of root tips, and collapse of the internal tissues. The shrivelling of PAA‐treated roots resulted from loss of water to the shoot in the transpiration stream, as the effect could be eliminated by removal of the shoot and sealing of the cut stump. HgCl2, a reagent known to reduce the hydraulic conductivity of root systems, caused the same root shrivelling effects as PAA. Long‐term growth of PAA‐treated plants was dependent upon the replacement of taproot systems by adventitious roots, which, initially at least, displayed greater tolerance of PAA. In aqueous solution, PAA exists in equilibrium with H2O2 and acetic acid, both of which were individually toxic, but acetic acid exhibited a syndrome of effects distinct from those of PAA, while the effects of H2O2 paralleled those of PAA more closely, suggesting that oxidative rather than acidic mechanisms were primarily responsible for the phytotoxicity of PAA solutions.
Electronic nose evaluation of onion headspace volatiles and bulb quality as affected by nitrogen, sulphur and soil type
Authors: ABBEY L , JOYCE D C , AKED J , SMITH B , MARSHALL C
Published: July 2006

Edaphic factors affect the quality of onions (Allium cepa). Two experiments were carried out in the field and glasshouse to investigate the effects of N (field: 0,120 kg ha−1; glasshouse: 0,108 kg ha−1), S (field: 0, 20 kg ha−1; glasshouse: 0, 4.35 kg ha−1) and soil type (clay, sandy loam) on onion quality. A conducting polymer sensor electronic nose (E‐nose) was used to classify onion headspace volatiles. Relative changes in the E‐nose sensor resistance ratio (%dR/R) were reduced following N and S fertilisation. A 2D Principal Component Analysis (PCA) of the E‐nose data sets accounted for c. 100% of the variations in onion headspace volatiles in both experiments. For the field experiment, E‐nose data set clusters for headspace volatiles for no N‐added onions overlapped (D2= 1.0) irrespective of S treatment. Headspace volatiles of N‐fertilised onions for the glasshouse sandy loam also overlapped (D2=1.1) irrespective of S treatment as compared with distinct separations among clusters for the clay soil. N fertilisation significantly (P < 0.01) reduced onion bulb pyruvic acid concentration (flavour) in both experiments. S fertilisation increased pyruvic acid concentration significantly (P < 0.01) in the glasshouse experiment, especially for the clay soil, but had no effect on pyruvic acid concentration in the field. N and S fertilisation significantly (P < 0.01) increased lachrymatory potency (pungency), but reduced total soluble solids (TSS) content in the field experiment. In the glasshouse experiment, N and S had no effect on TSS. TSS content was increased on the clay by 1.2‐fold as compared with the sandy loam. Onion tissue N: water‐soluble SO42− ratios of between five and eight were associated with greater %dR/R and pyruvic acid concentration values. N did not affect inner bulb tissue microbial load. In contrast, S fertilisation reduced inner bulb tissue microbial load by 80% in the field experiment and between 27% (sandy loam) and 92% (clay) in the glasshouse experiment. Overall, onion bulb quality discriminated by the E‐nose responded to N, S and soil type treatments, and reflected their interactions. However, the conventional analytical and sensory measures of onion quality did not correlate with %dR/R.
Resistance of potatoes transgenic for a cry1Ac9 gene, to Phthorimaea operculella (Lepidoptera: Gelechiidae) over field seasons and between plant organs
Authors: DAVIDSON M M , BUTLER R C , WRATTEN S D , CONNER A J
Published: July 2006

Stable performance of insect‐resistant transgenic plants across field seasons and between plant organs damaged by the insect pest is critical for management of this resistance in the field. To evaluate this, potato (Solanum tuberosum) lines transgenic for a cry1Ac9 gene with resistance to potato tuber moth (Phthorimaea operculella) were established in the field during the southern hemisphere summers of 1997/98, 1998/99 and 1999/00 as small field plots, each of 10 plants. Replicate plots of the non‐transgenic parent cultivars (at least one for every three independently derived transgenic lines) were planted randomly throughout the trials. Field‐grown foliage was challenged with larvae in the laboratory and a growth index (GI) was calculated for recovered larvae from each transgenic and non‐transgenic potato line. Larval growth on young and mature leaves, and on newly harvested or stored tubers was also measured in the laboratory. Foliage from the transgenic lines inhibited larval growth in all seasons tested. For both control and transgenic lines, larvae had slightly lower GIs when reared on mature leaves compared with young leaves, although the correlation between mean GI for young and mature transgenic leaves was high (r = 0.97). The correlation between the mean GIs of larvae on newly harvested tubers and on those stored for 5 months was also high (r = 1.0). However, the GIs of larvae on newly harvested transgenic tubers were larger than on transgenic tubers stored for 5 months. The relative growth indices (RGI = mean GI/number days before final weighing) of larvae reared on newly harvested tubers from transgenic lines were generally higher than those from young transgenic foliage, while the RGIs of larvae reared on non‐transgenic tubers were slightly lower than those fed non‐transgenic foliage. The correlation between mean RGIs of larvae fed tubers or foliage was 0.62. The transgenic potato lines exhibited stable resistance to larvae across field seasons, between affected plant organs, and between plant organs of different ages.
Take‐all and grain yields in sequences of winter wheat crops testing fluquinconazole seed treatment applied in different combinations of years
Authors: BATEMAN G L , GUTTERIDGE R J , JENKYN J F
Published: July 2006

A seed treatment containing fluquinconazole as the only active ingredient was tested in sequences of up to six consecutive crops of winter wheat. It was applied or not applied in each year, and was tested in all possible combinations with treatments applied in previous years. Take‐all was controlled effectively, and grain yield usually increased, when the disease intensity was moderate or severe in non‐treated crops, but control of the most severe take‐all did not result in acceptable yields or grain quality. Treatment of a first wheat or second wheat with little take‐all did not usually benefit the subsequent crop. Non‐treatment of a crop grown after a treated, diseased crop usually resulted in a marked increase in disease, indicating that treatment had delayed progress of the epidemic. Take‐all was controlled by treatment of a crop grown after a treated, diseased crop but the amount of control and of increased yield was often less than that in a treated crop grown after a non‐treated crop in the same crop sequence. Similar effects of seed treatment were apparent in crops grown on a site with take‐all decline. The alternative fungicide, silthiofam, applied as a seed treatment in the later years of some experiments, was usually as effective as fluquinconazole. From these experiments, it is recommended that: a) fluquinconazole seed treatment should be applied to a second or third wheat crop, grown after a first wheat crop that was managed to avoid rapid take‐all development (e.g. by avoiding very early sowing); b) a break crop should follow the treated crop; c) the seed treatment should not normally be used in longer sequences of wheat or on take‐all decline soil unless it is planned to follow the treated crop with a non‐cereal break.
Simulations and Measurements of Pressure Oscillations Caused by Vortex Ropes
Authors: Wang Zhengwei , Zhou Lingjiu
Published: July 2006

Pressure oscillations caused by vortex rope were measured in the draft tube of a prototype Francis turbine. The three-dimensional, unsteady Reynolds-averaged Navier-Stokes equations with the RNG κ−ϵ turbulence model were solved to model the flow within the entire flow path of the prototype hydraulic unit including the guide vanes, the runner, and the draft tube. The model was able to predict the pressure fluctuations that occur when operating at 67–83% of the optimum opening. The calculated frequencies and amplitudes of the oscillation show reasonable agreement with the experiment data. However, the results at 50% opening were not satisfactory. Pressure oscillations on the runner blades were found to be related to the precession of vortex ropes which caused pressure on the blades to fluctuate with frequencies of −fn+fd (fn is the rotational frequency and fd is vortex procession frequency). The peak-to-peak amplitudes of the pressure oscillations on the blades at the lower load conditions (67% opening) were higher than at higher load conditions (83% opening). Fluctuations on the suction side tended to be stronger than on the pressure side.
Ejection Interaction of Two Adjacent Micropumps
Authors: Cheng H.-P. , Chien C.-P.
Published: July 2006

This research intends to apply thermal bubble micropumps to motorcycle’s fuel atomizer system with ink and Stoddard solvent as the work liquids, and then utilize computational fluid dynamics to discuss the fluid interaction of two adjacent micropumps under continuous ejection with time lag, which covers the particle shape and movement track of ejected droplets, fluid interaction of ejected droplets, and velocity of droplets as well as work liquid replenishment. The micropump consists of 50 independent micropumps, with orifice of 50μm in diameter and working frequency of 5kHz. As shown in results, when the external air velocity is 0m∕sec, the velocity of droplets ejected later is faster than that of droplets ejected earlier. If the work liquid is ink, the replenishing rate of two adjacent micropumps is higher than that of single micropump. If the work liquid is Stoddard solvent, the replenishing rate of two adjacent micropumps is similar to that of single micropump. When the external air velocity is 15.0m∕sec and work liquid is ink, the velocity of droplet ejected later is slower than that of droplet ejected earlier, and the replenishing rate of two adjacent micropumps is lower than that of single micropump with the external air velocity of 0m∕sec. If the work liquid is Stoddard solvent, the velocities of two adjacent droplets are approximate, while the replenishing rates of two adjacent micropumps are approximate to that of single micropump with the external air velocity of 0m∕sec.
Computer‐aided diagnosis of pulmonary nodules on CT scans: Segmentation and classification using 3D active contours
Authors: Way Ted W. , Hadjiiski Lubomir M. , Sahiner Berkman , Chan Heang‐Ping , Cascade Philip N. , Kazerooni Ella A. , Bogot Naama , Zhou Chuan
Published: July 2006

We are developing a computer‐aided diagnosis (CAD) system to classify malignant and benign lung nodules found on CT scans. A fully automated system was designed to segment the nodule from its surrounding structured background in a local volume of interest (VOI) and to extract image features for classification. Image segmentation was performed with a three‐dimensional (3D) active contour (AC) method. A data set of 96 lung nodules (44 malignant, 52 benign) from 58 patients was used in this study. The 3D AC model is based on two‐dimensional AC with the addition of three new energy components to take advantage of 3D information: (1) 3D gradient, which guides the active contour to seek the object surface, (2) 3D curvature, which imposes a smoothness constraint in the direction, and (3) mask energy, which penalizes contours that grow beyond the pleura or thoracic wall. The search for the best energy weights in the 3D AC model was guided by a simplex optimization method. Morphological and gray‐level features were extracted from the segmented nodule. The rubber band straightening transform (RBST) was applied to the shell of voxels surrounding the nodule. Texture features based on run‐length statistics were extracted from the RBST image. A linear discriminant analysis classifier with stepwise feature selection was designed using a second simplex optimization to select the most effective features. Leave‐one‐case‐out resampling was used to train and test the CAD system. The system achieved a test area under the receiver operating characteristic curve of . Our preliminary results indicate that use of the 3D AC model and the 3D texture features surrounding the nodule is a promising approach to the segmentation and classification of lung nodules with CAD. The segmentation performance of the 3D AC model trained with our data set was evaluated with 23 nodules available in the Lung Image Database Consortium (LIDC). The lung nodule volumes segmented by the 3D AC model for best classification were generally larger than those outlined by the LIDC radiologists using visual judgment of nodule boundaries.