Self-oriented regular arrays of carbon nanotubes and their field emission properties   总被引：4，自引：0，他引：4  

S Fan  MG Chapline  NR Franklin  TW Tombler  AM Cassell  H Dai 《Science (New York, N.Y.)》1999,283(5401):512-514

The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-assembly for orientation. The mechanisms of nanotube growth and self-orientation are elucidated. The well-ordered nanotubes can be used as electron field emission arrays. Scaling up of the synthesis process should be entirely compatible with the existing semiconductor processes, and should allow the development of nanotube devices integrated into silicon technology.  相似文献   

Highly specific assays to detect isolates of Pseudomonas syringae pv. actinidiae biovar 3 and Pseudomonas syringae pv. actinidifoliorum directly from plant material          下载免费PDF全文

M. T. Andersen  M. D. Templeton  J. Rees‐George  J. L. Vanneste  D. A. Cornish  J. Yu  W. Cui  T. J. Braggins  K. Babu  J. F. Mackay  E. H. A. Rikkerink 《Plant pathology》2018,67(5):1220-1230

Pseudomonas syringae pv. actinidiae (Psa) is responsible for bacterial canker of kiwifruit. Biovar 3 of Psa (Psa3) has been causing widespread damage to yellow‐ and green‐fleshed kiwifruit (Actinidia spp.) cultivars in all the major kiwifruit‐producing countries in the world. In some areas, including New Zealand, P. syringae pv. actinidifoliorum (Pfm), another bacterial pathogen of kiwifruit, was initially classified as a low virulence biovar of Psa. Ability to rapidly distinguish between these pathovars is vital to the management of bacterial canker. Whole genome sequencing (WGS) data were used to develop PCR assays to specifically detect Psa3 and Pfm from field‐collected material without the need to culture bacteria. Genomic data from 36 strains of Psa, Pfm or related isolates enabled identification of areas of genomic variation suitable for primer design. The developed assays were tested on 147 non‐target bacterial species including strains likely to be found in kiwifruit orchards. A number of assays did not proceed because although they were able to discriminate between the different Psa biovars and Pfm, they also produced amplicons from other unrelated bacteria. This could have resulted in false positives from environmental samples, and demonstrates the care that is required when applying assays devised for pure cultures to field‐collected samples. The strategy described here for developing assays for distinguishing strains of closely related pathogens could be applied to other diseases with characteristics similar to Psa.  相似文献   

Dissolved organic matter leaching in some contrasting New Zealand pasture soils     

A. Ghani  K. Müller  M. Dodd  A. Mackay 《European Journal of Soil Science》2010,61(4):525-538

Leaching of dissolved organic matter (DOM) from pastoral soils is increasingly seen as an important but poorly understood process. This paper examined the relationship between soil chemical properties, microbial activity and the losses of dissolved organic carbon (DOC) and nitrogen (DON) through leaching from six pasture soils. These soils differed in carbon (C) (4.6–14.9%) and nitrogen (N) (0.4–1.4%) contents and in the amount of organic C and N that had accumulated or been lost in the preceding 20+ years (i.e. −5131 to +1624 kg C ha⁻¹ year⁻¹ and −263 to +220 kg N ha⁻¹ year⁻¹, respectively). The paper also examined whether between‐soil‐type differences in DOC and DON leaching was a major explanatory factor in the observed range of soil organic matter (SOM) changes in these soils. Between 280 and 1690 kg C ha⁻¹ year⁻¹ and 28–117 kg N ha⁻¹ year⁻¹ leached as DOC and DON, respectively, from the six soils in a lysimeter study, with losses being greater from two poorly drained gley soils. Losses of C and N of this magnitude, while at the upper end relative to published data, could not fully explain the losses at Rawerawe, Bruntwood and Lepperton sites reported by Schipper et al. (2007) . The study highlights the leaching of DOM as a significant pathway of loss of C and N in pasture soils that is often ignored or given little attention in predictive models and nutrient budgeting. Leaching losses of DOC and DON alone, or in combination with slightly increased respiration losses of SOM given a 0.2°C increase in the mean annual soil temperature, do not fully explain long‐term changes in the SOM observed at these sites. When soils examined in the present study were separated on the basis of drainage class, the losses of DOC by leaching were correlated with both total and hot‐water extractable C (HWC), the latter being a measure of the labile SOM fraction. Basal microbial CO₂ respiration rates, which varied between 1 and 3.5 µg CO₂‐C g⁻¹ soil hour⁻¹ in surface soils (0–75‐mm depth), was also linked to HWC and the quantities of C lost as DOC. Adoption of the HWC method as an approach that could be used as a proxy for the direct measurement of the soil organic C lost by leaching as DOC or respired needs to be examined further with a greater number of soils. In comparison, a poor relationship was found between the hot‐water extractable N (HWN) and loss of DON by leaching, despite HWN previously being shown to be a measure of the mineralizable pool of N in soils, possibly reflecting the greater competition for N than C in these soils.  相似文献   

Hyperoxaluria,hyperglycoluria and renal oxalosis in Gilbert's potoroos (Potorous gilbertii)          下载免费PDF全文

D Forshaw  AM Horwitz  K Ellard  JA Friend  L Greed  M Metz 《Australian veterinary journal》2017,95(7):250-258

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Protein Composition of Seminal Plasma in Fractionated Stallion Ejaculates     

AM Kareskoski  MM Rivera del Alamo  K Güvenc  T Reilas  JJ Calvete  H Rodriguez‐Martinez  M Andersson  T Katila 《Reproduction in domestic animals》2011,46(1):e79-e84

Seminal plasma (SP) contains several types of compounds derived from the epididymides and accessory glands. The aim of this study was to examine the protein composition of different ejaculate fractions. Trial I: fractionated ejaculates were collected from two normal and two subfertile stallions. Samples containing pre‐sperm fluid and the first sperm‐rich jets (HIGH‐1), the main sperm‐rich portion (HIGH‐2), the jets with low sperm concentrations (LOW), and a combined whole‐ejaculate (WE) sample was centrifuged, and the SP was filtered and frozen. A part of each SP sample was stored (5°C, 24 h) with spermatozoa from HIGH‐2 and skim milk extender. Sperm motility was evaluated after storage in extender mixed with the stallion’s own SP or SP from one of the other stallions (sperm from a normal stallion stored in SP from a subfertile stallion and vice versa). Protein composition was analysed using reverse‐phase liquid chromatography (RP‐HPLC), N‐terminal sequencing and mass spectrometry. The area‐under‐the‐curve (AUC) was used for quantitative comparison of proteins within fractions. Trial II: semen samples were collected from seven stallions. Fractions with the highest (HIGH) and lowest (LOW) sperm concentrations and WE samples were examined using SDS‐PAGE and densitometry. No significant differences emerged between fractions in the AUC‐values of the Horse Seminal Protein‐1 (HSP‐1) and HSP‐2 peaks, or the peak containing HSP‐3 and HSP‐4 (HSP‐3/4). Levels of HSP‐1, HSP‐2 and HSP‐3/4 were not significantly correlated with total sperm motility, progressive sperm motility or average path velocity after storage. Significant differences between ejaculate fractions in the amount of different protein groups present in SP were not found in Trial I; but in Trial II, the proteins in the 60–70 kDa range were more abundant in LOW than in HIGH and WE, indicating that this band contained proteins derived mainly from the seminal vesicles, which produce most of the SP in LOW.  相似文献   

Tick paralysis in dogs and cats in Australia: treatment and prevention deliverables from 100 years of research     

AM Padula  EM Leister  RA Webster 《Australian veterinary journal》2020,98(1-2):53-59

This review of tick paralysis caused by Ixodes holocyclus in Australia addresses the question: What are the key discoveries that have enabled effective treatment and prevention of tick paralysis in dogs and cats? Critical examination of 100 years of literature reveals that arguably only three achievements have advanced treatment and prevention of tick paralysis in animals. First, the most significant treatment advance was the commercial availability of tick antiserum in the 1930s. Hyperimmune serum currently remains the only specific anti-paralysis tick therapy available to veterinarians in Australia. Second, advances in veterinary critical care have increased survival rates of the most severely affected dogs and cats. Critical care advancements have been enabled through specialised veterinary hospitals that can provide appropriate care 24 h a day, and advanced training of veterinarians, veterinary nurses and technicians. Third, perhaps that biggest advance of all in the last 100 years of research has been the commercial availability of the isooxazoline class of acaricidal preventatives in Australia specifically for I. holocyclus. This highly effective class of preventatives offers long duration of action, low cost, spot-on or oral formulations and a low rate of adverse reactions. Animal owners and veterinarians now have the most useful tool of all – a reliable preventative. This review reveals the key events in research over the last 100 years and the tortuous pathway to delivering better treatment and preventative options for this enigmatic Australian parasite.  相似文献   

Red-bellied black snake (Pseudechis porphyriacus) envenomation in 17 dogs: clinical signs,coagulation changes,haematological abnormalities,venom antigen levels and outcomes following treatment with a tiger-brown snake antivenom     

ER Finney  AM Padula  EM Leister 《Australian veterinary journal》2020,98(7):319-325

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SnakeMap: four years of experience with a national small animal snake envenomation registry     

M Boller  K Kelers  MA Stevenson  KD Winkel  S Hardjo  J Heller  PR Judge  HM Ong  AM Padula  C Reddrop  LCP Santos  CR Sharp  L Smart  KL Swindells  D Tabrett  JR Wierenga 《Australian veterinary journal》2020,98(9):442-448

SnakeMap is a national cloud-based, veterinary snakebite registry. It was designed to prospectively collect data of the clinical circumstances and temporospatial information on cases of snake envenomation in dogs and cats. We herein introduce the project and summarise the data from the first 4 years of SnakeMap. The registry is a veterinary community-based online database allowing case entry from veterinary hospitals across Australia. Registry data comprise hospital characteristics, patient characteristics, envenoming snake type, treatment and outcome variables, including time and geolocation of the snake bite. We present summative information on select key variables from the SnakeMap registry (1 July 2015 to 30 June 2019). Twenty-eight hospitals from 6 states/territories entered 624 cases into the registry, including 419 dogs (67%) and 205 cats (33%). Bite time was available in 216 animals of which 90 (42%) were reported to be bitten in the 3 hours between 03:00 pm and 05:59 pm; median bite to presentation interval was 60 (interquartile range [IQR] 30, 211) minutes in dogs and 95 (IQR 41, 238) minutes in cats. Bites occurred in the owner's yard in 356 dogs (85%) and 53 cats (26%). A snake venom detection kit was used in 172 cases (28%) and antivenom was administered in 523 cases (85%). Most animals (n = 534, 88%) survived to discharge (median hospitalisation of 25 [IQR 16, 62] hours). SnakeMap effectively collects relevant clinical data from dogs and cats with presumed snake bite and provides locally specific information on the epidemiology of snake envenomation in small animals.  相似文献   

A glasshouse progeny test for resistance to tuber blight (Phytophthora infestans)     

R. L. Wastie  P. D. S. Caligari  Helen E. Stewart  G. R. Mackay 《Potato Research》1987,30(3):533-538

Summary The susceptibility to tuber blight (Phytophthora infestans) of seedling progenies from ten crosses involving resistant and susceptible parents was assessed by inoculating tubers grown in the glasshouse and in the field. The mean level of tuber blight in each progeny corresponded with the resistance category of the cross, and the rank order of increasing susceptibility was almost identical in both tests. It is suggested that two samples of ten glasshouse-grown seedlings, each seedling providing two tubers harvested as the plants begin flowering, is an adequate sample size on which to predict the tuber blight susceptibility of a progeny.

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Zusammenfassung Die Anf?lligkeit gegen Knollenbraunf?ule von 10 Nachkommen, einmal von Knollen im Gew?chshaus angezogener S?mlinge (1984), zum anderen von im Feld gewachsener Pflanzen (1985), wurde verglichen. Vier Nachkommen von resistenten Eltern, drei von anf?lligen Eltern und drei aus ‘resistent x anf?llig’-Kreuzungen (Tabelle 1) wurden in zwei Blocks von 40 Pflanzen 9 Wochen lang in 10 cm-T?pfen angezogen. Acht Proben von 10 Pflanzen wurden von jedem Nachkommen entnommen (und zwei Knollen von jedem Topff zu Beginn der Blüte Anfang September), durch Tauchen in eine Zoosporen-Suspension vonPhytophthora infestans inokuliert, und 8 Tage danach die Anzahl der infizierten Knollen festgestellt. Der mittlere Grad von Braunf?ule bei jedem Nachkommen entsprach der Resistenzgruppe der Kreuzung (Tabellen 2 und 3). Im Gew?chshaus angezogene Knollen der gleichen Nachkommen wurden im Feld in zwei Wiederholungen (Blocks) mit 16 bzw. 23 S?mlingen je Nachkommen ausgepflanzt. Die beiden Blocks wurden mit Schwester-Knollen bepflanzt, so dass jeder S?mling in beiden Blocks vorhanden war. Die Knollen wurden nach 16 Wochen geerntet, danach inokuliert und wie zuvor geschildert ausgewertet. Die Rangfolge mit ansteigender Anf?lligkeit war in beiden Tests fast identisch (Tabelle 2). Daraus wird geschlossen, dass zwei Partien von 10 S?mlingen mit je 2 Knollen eine angemessene Probengr?sse zur Vorhersage der Knollenf?ule-Anf?lligkeit eines Nachkommens darstellen (Tabelle 4). Der Test ist schnell und einfach in der Handhabung und erm?glicht in Verbindung mit einer Prüfung der Krautf?uleanf?lligkeit die M?glichkeit einer Auslese sowohl auf Krautf?ule als auch auf Knollen-Braunf?ule im gleichen Jahr.

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Résumé La sensibilité de 10 lignées au mildiou du tubercule est évaluée à partir de tubercules issues de plantules cultivées en serre (1984) et en plein champ (1985). Quatre lignées de parents résistants, 3 de parents sensibles et 3 de croisements résistant x sensible (tableau 1) sont cultivés dans deux blocs de 40 plantes mises en pots de 10 cm pendant 9 semaines. Huit échantillons de dix plantes sont prélevés dans chaque lignée et deux tubercules sont retirés de chaque pot au premier stade de la floraison début septembre, puis inoculés par trempage dans une suspension de zoospores deP. infestans; le nombre de tubercules contaminés est enregistré après 8 jours. Le niveau moyen de contamination dans chaque lignée correspond à la catégorie de résistance du croisement (tableaux 2 et 3). Les tubercules issus de la serre et appartenant aux mêmes lignées sont plantés en plein champ dans deux blocs, chacun comprenant deux échantillons de 16 à 23 plantules par lignée. Les deux blocs sont plantés avec des tubercules d'un même pied, de sorte qu'il y a deux répétitions pour chaque plantule. Les tubercules sont récoltés après 16 semaines puis inoculés et notés comme précédemment. Le classement par ordre croissant de sensibilité est pratiquement identique dans les deux tests (tableau 2). En conclusion, deux lots de 10 plantules, chacune produisant deux tubercules, constituent un échantillon approprié pour analyser la sensibilité d'une lignée au mildiou des tubercules (tableau 4). Le test est simple et rapide, et combiné au test sur feuille, il offre la possibilité de détecter la résistance au mildiou des feuilles et des tubercules dans la même année.

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Insular pest control within a metapopulation context     

James C. Russell  Jamie W.B. Mackay  Jawad Abdelkrim 《Biological conservation》2009,142(7):1404-1410

Introduced pests threaten many species and their control is generally beneficial for conservation, particularly on islands where complete eradication is possible. Unfortunately on ‘nearshore’ islands neighbouring source populations exist and unaided reinvasion is likely. Pest control programmes at these sites thus require a metapopulation context to adequately manage movements between source and sink populations. We investigated the ecology of introduced ship rats (Rattus rattus) on a nearshore island, and gene flow with adjacent mainland populations, in order to understand the metapopulation dynamics and relative levels of pest control required within the landscape. We sampled the entire population by trapping (n = 30), achieving eradication, and found a low rat density (3.2 ha⁻¹) indicative of a sink population. Seed and other plant material constituted the major dietary component of rats. Despite its proximity to mainland source populations, the island population was genetically distinct with reduced allelic diversity caused by a recent reinvasion founder effect. Genetic analyses also detected recent migrants between the populations. In contrast, two mainland populations separated by a similar distance displayed complete genetic mixing. The small water gap therefore provides a sufficient barrier to lower the migration rate to the island and delay reinvasion, which nonetheless eventually happens. In order to maintain nearshore islands pest-free, conservation management will require a metapopulation approach simultaneously focusing on both island and source population pest control.  相似文献