Tunneling into a single magnetic atom: spectroscopic evidence of the kondo resonance     

V Madhavan  W Chen  T Jamneala  MF Crommie  NS Wingreen 《Science (New York, N.Y.)》1998,280(5363):567-569

The Kondo effect arises from the quantum mechanical interplay between the electrons of a host metal and a magnetic impurity and is predicted to result in local charge and spin variations around the magnetic impurity. A cryogenic scanning tunneling microscope was used to spatially resolve the electronic properties of individual magnetic atoms displaying the Kondo effect. Spectroscopic measurements performed on individual cobalt atoms on the surface of gold show an energetically narrow feature that is identified as the Kondo resonance-the predicted response of a Kondo impurity. Unexpected structure in the Kondo resonance is shown to arise from quantum mechanical interference between the d orbital and conduction electron channels for an electron tunneling into a magnetic atom in a metallic host.  相似文献   

Investigation of the effect of Equivac® HeV Hendra virus vaccination on Thoroughbred racing performance          下载免费PDF全文

K Schemann  EJ Annand  PA Reid  MF Lenz  PC Thomson  NK Dhand 《Australian veterinary journal》2018,96(4):132-141

Objective

To evaluate the effect of Equivac® HeV Hendra virus vaccine on Thoroughbred racing performance.

Design

Retrospective pre‐post intervention study.

Methods

Thoroughbreds with at least one start at one of six major south‐eastern Queensland race tracks between 1 July 2012 and 31 December 2016 and with starts in the 3‐month periods before and after Hendra virus vaccinations were identified. Piecewise linear mixed models compared the trends in ‘Timeform rating’ and ‘margin to winner’ before and after initial Hendra virus vaccination. Generalised linear mixed models similarly compared the odds of ‘winning’, ‘placing’ (1st–3rd) and ‘winning any prize money’. Timeform rating trends were also compared before and after the second and subsequent vaccinations.

Results

Analysis of data from 4208 race starts by 755 horses revealed no significant difference in performance in the 3 months before versus 3 months after initial Hendra vaccination for Timeform rating (P = 0.32), ‘Margin to winner’ (P = 0.45), prize money won (P = 0.25), wins (P = 0.64) or placings (P = 0.77). Further analysis for Timeform rating for 7844 race starts by 928 horses failed to identify any significant change in Timeform rating trends before versus after the second and subsequent vaccinations (P = 0.16) or any evidence of a cumulative effect for the number of vaccines received (P = 0.22).

Conclusion

No evidence of an effect of Hendra virus vaccination on racing performance was found. The findings allow owners, trainers, industry regulators and animal health authorities to make informed decisions about vaccination.  相似文献   

Vesicles Cytoplasmic Injection: An Efficient Technique to Produce Porcine Transgene‐Expressing Embryos          下载免费PDF全文

CG Luchetti  RJ Bevacqua  MS Lorenzo  MF Tello  M Willis  CP Buemo  DM Lombardo  DF Salamone 《Reproduction in domestic animals》2016,51(4):501-508

The use of vesicles co‐incubated with plasmids showed to improve the efficiency of cytoplasmic injection of transgenes in cattle. Here, this technique was tested as a simplified alternative for transgenes delivery in porcine zygotes. To this aim, cytoplasmic injection of the plasmid alone was compared to the injection with plasmids co‐incubated with vesicles both in diploid parthenogenic and IVF zygotes. The plasmid pcx‐egfp was injected circular (CP) at 3, 30 and 300 ng/μl and linear (LP) at 30 ng/μl. The experimental groups using parthenogenetic zygotes were as follows: CP naked at 3 ng/μl (N = 105), 30 ng/μl (N = 95) and 300 ng/μl (N = 65); Sham (N = 105); control not injected (N = 223); LP naked at 30 ng/μl (N = 78); LP vesicles (N = 115) and Sham vesicles (N = 59). For IVF zygotes: LP naked (N = 44) LP vesicles (N = 94), Sham (N = 59) and control (N = 79). Cleavage, blastocyst and GFP+ rates were analysed by Fisher's test (p < 0.05). The parthenogenic CP naked group showed lower cleavage respect to control (p < 0.05). The highest concentration of plasmids to allow development to blastocyst stage was 30 ng/μl. There were no differences in DNA fragmentation between groups. The parthenogenic LP naked group resulted in high GFP rates (46%) and also allowed the production of GFP blastocysts (33%). The cytoplasmic injection with LP vesicles into parthenogenic zygotes allowed 100% GFP blastocysts. Injected IVF showed higher cleavage rates than control (p < 0.05). In IVF zygotes, only the use of vesicles produced GFP blastocysts. The use of vesicles co‐incubated with plasmids improves the transgene expression efficiency for cytoplasmic injection in porcine zygotes and constitutes a simple technique for easy delivery of plasmids.  相似文献   

Effect of a second treatment of prostaglandin F2α during the Ovsynch program on fixed-time artificial insemination conception rates and luteolysis in split-calving,pasture-fed dairy cows     

JM Rheinberger  DD Colson  DS Beggs  PD Mansell  MA Stevenson  RJ Rheinberger  MF Pyman 《Australian veterinary journal》2020,98(5):190-196

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Isolation and Differentiation of Mesenchymal Stem Cells From Bovine Umbilical Cord Blood     

MF Raoufi  P Tajik  MM Dehghan  F Eini  A Barin 《Reproduction in domestic animals》2011,46(1):95-99

Currently, mesenchymal stem cells (MSCs) are used in veterinary clinical applications. Bone marrow and adipose tissue are the most common sources of stem cells derived from adult animals. However, cord blood which is collected non‐invasively is an alternative source of stem cells other than bone marrow and adipose tissue. Moreover, high availability and lower immunogenicity of umbilical cord blood (UCB) haematopoietic stem cells compared to other sources of stem cell therapy such as bone marrow have made them a considerable source for cell therapy, but MSCs is not highly available in cord blood and their immunogenicity is poorly understood. In this study, the cells with spindle morphology from 7 of 9 bovine UCB samples were isolated and cultured. These mesenchymal stromal cells were successfully differentiated to osteocytes, chondrocytes and adipocytes. In addition, Oct‐4 and SH3 were determined by RT‐PCR assay. It is the first report of isolation, culture, characterization and differentiation of bovine umbilical stem cells.  相似文献   

Phenotypic and genotypic characterisation of Pasteurella multocida isolated from pigs at slaughter in New Zealand     

R Jamaludin  PJ Blackall  MF Hansen  S Humphrey  M Styles 《New Zealand veterinary journal》2013,61(3):203-207

AIMS: To examine pigs at slaughter in New Zealand for the presence of Pasteurella multocida, and to determine for isolates, their biochemical profiles, somatic and capsular types, and the presence or absence of the HSB and toxA genes, associated with haemorrhagic septicaemia (HS) and progressive atrophic rhinitis (PAR), respectively.

METHODS: Swabs from 173 lungs, 158 palatine tonsils and 82 nasal passages of pigs at two abattoirs in New Zealand were cultured for P. multocida using conventional techniques, and isolated colonies were subjected to biochemical tests for identification of biovars. Somatic serotyping was conducted using an agar gel immunodiffusion (AGID) test. Polymerase chain reaction (PCR) assays were used to confirm phenotypic identification of colonies using species-specific primers, capsule type using serogroup-specific primers and multiplex PCR, and to test for the presence of HSB and toxA genes.

RESULTS: Pasteurella multocida was isolated from 11/173 (6.4%) lung, 32/158 (20.2%) palatine tonsil and 5/82 (6.1 %) nasal swab samples, a total of 48 isolates from 413 samples (11.6%). Isolation rates per farm ranged from 1–53% of tissue samples collected from pigs 5–6 months of age. On phenotypic characterisation, isolates were allocated to seven main biovars, viz 1, 2, 3, 5, 9, 12, and a dulcitol-negative variant of Biovar 8, the majority (30/48) being Biovar 3. Of the 42 isolates for which somatic serotyping was conducted, 10% were Serovar 1, 79% were Serovar 3, 2% were Serovar 6,1, 2% were Serovar 12, and 7% could not be typed. All 48 isolates were confirned as P. multocida using a species-specific PCR. In the capsular multiplex PCR, 92% of isolates were Capsular (Cap) type A, 2% were Cap D, and 6% could not be typed. None of the samples were positive for the HSB or toxA genes.

CONCLUSION: Serovars or capsular types of P. multocida associated with HS or PAR in pigs were not detected. Establishment of species-specific, capsular and toxin PCR assays allowed the rapid screening of isolates of P. multocida, while serotyping provided an additional tool for epidemiological and tracing purposes.  相似文献   

Detection of Mycoplasma conjunctivae in sheep affected with conjunctivitis and infectious keratoconjunctivitis     

MXJ Motha  J Frey  MF Hansen  R Jamaludin  KM Tham 《New Zealand veterinary journal》2013,61(4):186-190

AIM: To determine the aetiolog y of a recurring and severe form of infectious keratoconjunctivitis (IKC) in sheep.

METHODS: Five sheep flocks that had experienced a severe form of IKC were examined. Clinical history, conjunctival swabs and blood samples were collected from affected animals. Culture for bacteria, and also specifically for Mycoplasma and Chlamydophila spp, and detection of Mycoplasma conjunctivae DNA by polymerase chain reaction (PCR) were attempted. Serum samples were tested for antibodies to M. agalactiae, M. capricolum, M. conjunctivae and Chlamydophila spp.

RESULTS: Mycoplasma conjunctivae DNA was detected using PCR in 3/5 flocks, and in all flocks antibodies to M. conjunctivae were detected in sera. A pure growth of Branhamella ovis was cultured from conjunctival swabs from a small proportion of sheep in two flocks. No other pathogens were detected.

CONCLUSIONS: This investigation demonstrated that M. conjunctivae was a primary pathogen causing severe IKC in sheep, and is the first report of detection of this organism in sheep in New Zealand. Introduction of clinically normal carrier sheep appeared to have caused the outbreaks.  相似文献   

Histological and biomechanical effects of palatal sclerotherapy in the horse using sodium tetradecyl sulfate     

Juan A. Muñoz  Marcel Marcoux  Valérie Picandet  Christine L. Theoret  Marie-France Perron  Olivier M. Lepage 《Veterinary journal (London, England : 1997)》2010,183(3):316-321

Palatal sclerotherapy using sodium tetradecyl sulfate has been suggested as a treatment for dorsal displacement of the soft palate in young Standardbred horses. The present study evaluated histological and biomechanical changes in the equine soft palate following trans-endoscopic treatment with a low dose of this compound. Two horses were euthanased and examined at 2 weeks and at 1, 2, 4 and 6 months post-sclerotherapy, while two further horses served as untreated controls. The technique was easily performed in all cases without major complications. On histological examination there was no evidence of palatal necrosis, inflammation or fibrosis in any of the treated or control animals. There was no variation in the density of palatal connective tissue between individuals, and on biomechanical assessment no significant difference in the stiffness of the palatal tissue was found between treated and control horses at any time. The lower dose of sodium tetradecyl sulfate used in this study relative to previous reports, might explain the absence of tissue alterations. This method of sclerotherapy did not alter the morphology or biomechanical properties of normal equine soft palates.  相似文献   

Factors associated with colostrum immunoglobulin G concentration in northern‐Victorian dairy cows          下载免费PDF全文

AJ Phipps  DS Beggs  AJ Murray  PD Mansell  MF Pyman 《Australian veterinary journal》2017,95(7):237-243

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Real-time ultrasonography for pregnancy diagnosis and foetal ageing in fallow deer     

MF LENZ  AW ENGLISH  A DRADJAT 《Australian veterinary journal》1993,70(10):373-375

SUMMARY Three groups of 15 to 17 adult fallow does with some additional yearling does in 2 of the groups were treated to synchronise oestrous cycles, and mated. All does were scanned by ultrasound at 4 weeks of gestation and at weekly intervals from week 7 to week 14 of gestation. Growth rates of 13 foetal and uterine characters, which have been used for ageing foetuses of red deer, were similar for adult and yearling does and among the 3 groups. Transrectal ultrasound scanning was a reliable and accurate means of detecting pregnancy and of ageing foetuses of fallow deer during weeks 7 to 17 of pregnancy.  相似文献