Giant Friedel Oscillations on the Beryllium(0001) Surface     

PT Sprunger  L Petersen  EW Plummer  E Laegsgaard  F Besenbacher 《Science (New York, N.Y.)》1997,275(5307):1764-1767

Large-amplitude electron density oscillations were observed on a Be(0001) surface by means of variable-temperature scanning tunneling microscopy. Fourier transforms of the images showed a ring of radius 2kF, where kF is the Fermi wave vector of the Be(0001) surface state. This wavelength was expected from Friedel oscillations caused by electronic screening of surface defects, but the amplitude of the waves for energies near the Fermi energy was anomalously large and inconsistent with the Friedel concept of screening. The enhanced amplitude of the waves must be a many-body effect, either in the electron gas (possibly an incipient charge density wave) or in the response of the lattice (electron-phonon coupling).  相似文献   

The Trouble with Medical Journals - by Richard Smith     

Richard EW Halliwell 《Veterinary dermatology》2008,19(4):240-241

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Platelet‐Activating Factor and Evidence of Oxidative Stress in the Bronchoalveolar Fluid of Thoroughbred Colts during Race Training     

P.V. Michelotto Jr  L.A. Muehlmann  A.L. Zanatta  E.W.R. Bieberbach  L.C. Fernandes  A. Nishiyama 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2010,24(2):414-419

Background: Inflammatory airway disease (IAD) is prevalent in young racehorses during training, being the 2nd most commonly diagnosed ailment interrupting training of 2‐year‐old Thoroughbred racehorses. Hypothesis: That stabling and exercise cause oxidative stress, release of platelet‐activating factor (PAF) and inflammation in airways of Thoroughbred colts. Animals: Colts in breeding farms (NC, n = 45), stabled for 30 days (EC, n = 40), and race trained (EX, n = 34). Methods: Cytological profile and parameters of bronchoalveolar lavage fluid (BALF) related to oxidative stress, bioactivity of the proinflammatory mediator PAF, catalase activity, and alveolar macrophage function. Results: Percentages of neutrophils and eosinophils in the BALF of the EX group were higher (5.4 ± 6.4% versus 0.9 ± 1.2%) than the upper limits for normal horses (3–5%). BALF from the EX group (45.6 ± 2.8 cells/μL of BALF) also displayed significantly (P= .017) higher total nucleated cell count. PAF bioactivity and the total protein concentration in the BALF were higher in the EX group (0.0683 ± 0.076 versus 0.0056 ± 0.007 340 : 380 nm ratio P= .0039, 0.36 ± 0.30 versus 0.14 ± 0.15 mg of proteins/mL of BALF P < .001). Concentration of BALF hydroperoxides was higher in the EC group (104.7 ± 80.0 versus 35.2 ± 28.0 nmol/mg of proteins, P= .013) and catalase activity was higher in the EX group (0.24 ± 0.16 versus 0.06 ± 0.02 μmol H₂O₂/min/mg of proteins, P= .0021). Alveolar macrophage phagocytosis (P= .048) as well as production of superoxide anion (P= .0014) and hydrogen peroxide (P= .0011) were significantly lower in EX group. Conclusions and Clinical Importance: Further studies should be performed to elucidate the role of PAF in the pathophysiology of IAD. Its presence in bronchoalveolar fluid of young athletic horses makes it a potential therapeutic target to be investigated.  相似文献   

Settling of insecticide from dip wash mixed with dam water and zinc sulphate and used to control sheep lice (Bovicola ovis)     

PW MORCOMBE  DF HIDE†  GE YOUNG  EW ARMSTRONG‡  LE MILLAR§  ARB HIGGS¶ 《Australian veterinary journal》1995,72(11):411-414

SUMMARY Insecticidal dipping fluid emulsions, mixed in vitro in dam water containing suspended clay particles and 1% w/v zinc sulphate, were analysed to determine rates of settling of diazinon, cyhalothrin and cypermethrin. Fifteen minutes after mixing, the concentration of the insecticides 5 cm below the surface had declined by 72.5%, 72.8% and 89.4%, respectively. On remixing, the concentration of insecticide in suspension was close to or greater than the initial concentration. In 2 trials, lice were eradicated from sheep showered with dip wash mixed in cloudy dam water to which 1% w/v of zinc sulphate was added. In 12 flock treatments in which 1000 to 2000 sheep were dipped with added zinc sulphate, the concentration of insecticide remained above the minimum lethal for susceptible strains of lice. However, lice were still present 6 months later in 8 of these flocks. When zinc sulphate is added to dip wash, agitation is needed to maintain the insecticide in suspension.  相似文献   

Pulmonary inflammation due to exercise-induced pulmonary haemorrhage in Thoroughbred colts during race training     

Michelotto PV  Muehlmann LA  Zanatta AL  Bieberbach EW  Kryczyk M  Fernandes LC  Nishiyama A 《Veterinary journal (London, England : 1997)》2011,190(2):e3-e6

This study investigated the putative roles of inflammation and platelet-activating factor (PAF) in exercise-induced pulmonary haemorrhage (EIPH). Two-year-old Thoroughbred colts (n=37) were exercised on a racetrack for 5months before commencement of the study. Each colt was then exercised at 15-16m/s over 800-1000m and broncho-alveolar lavage fluid (BALF) was collected 24h later. The colts were subsequently divided into two groups on the basis of BALF analysis; an EIPH-positive group (presence of haemosiderophages, n=23) and an EIPH-negative group (absence of haemosiderophages, n=14). BALF from the EIPH-positive group had a significantly higher protein concentration (0.39±0.28 vs. 0.19±0.12mg/mL, P=0.031), higher PAF bioactivity (0.18±0.12 vs. 0.043±0.05 340:380nm ratio, P=0.042) and a higher lipid hydroperoxide concentration compared to the EIPH-negative group. There was also a lower nitrite concentration and reduced production of superoxide anion and hydrogen peroxide by alveolar macrophages in the EIPH-positive group. There was evidence of pulmonary inflammation and a decreased innate immune response of alveolar macrophages in EIPH-positive colts compared with the EIPH-negative group.  相似文献