SCINTIGRAPHIC CHARACTERIZATION OF THE EQUINE FOREDIGIT AND METACARPOPHALANGEAL REGION FROM BIRTH TO SIX MONTHS OF AGE     

Michael R.  Metcalf  DVM  MS  Louis C.  Sellett  MS  James E.  Smallwood  DVM  MS  Donald E.  Thrall  DVM  PhD  Ben D.  Harrington  DVM 《Veterinary radiology & ultrasound》1989,30(3):111-118

Both foredigits and metacarpophalangeal joints of six Quarter Horse foals were scanned serially to six months of age using ⁹⁹Tc-methylene diphosphonate. Dorsal scans were made on day 1 and at two, four, six, ten, 14, 18, 22 and 26 weeks of age. Scans were assessed visually for distal third metacarpal, proximal phalangeal, and middle phalangeal physeal appearance and closure. Scans were also evaluated by computer region-of-interest (ROI) and line-profile analysis to characterize the physes quantitatively. Physeal region radioactivity relative to a disphyseal reference region was greatest at four weeks for all physes. Scintigraphic physeal closure of all physes occurred at approximately six months of age with a range of four and one half to greater than six months. The study was conducted to allow better assessment of diffuse and focal physeal disease by determining developmental times at which normal physeal region radioactivity has decreased enough to not obscure abnormal radioactivity and by quantifying scintigraphic physeal appearance which enables computer analysis to detect visually indeterminate physeal abnormalities.  相似文献   

Genetic Variability and Structure of Canadian Populations of the Sapstain Fungus Ceratocystis resinifera     

Morin C  Breuil C  Bernier L 《Phytopathology》2004,94(12):1323-1330

ABSTRACT Genomic DNA was extracted from 129 isolates of Ceratocystis resinifera, a species belonging to the C. coerulescens complex, and 19 polymorphic random amplified polymorphic DNA markers were used to study the population genetic structure of this fungus. The analysis suggested a moderate value for genetic diversity (H(S) = 0.209). However, when monomorphic markers and rare alleles, representing 89 markers, also were included in the calculation, the genetic diversity of Canadian populations of C. resinifera appeared to be much lower (H(S) = 0.045). This could be explained by two hypotheses: (i) recent introduction of this species into North America and (ii) clonal reproduction (by selfing). No specialization by C. resinifera for coniferous tree species was observed based on genetic differentiation index between isolates sampled from Pinus and Picea spp. and on phylogenetic analysis using Dice coefficient of association. In spite of a low genetic diversity, a very high genetic differentiation was observed among the nine geographical populations studied (F(ST) = 20.8%). The genetic differences were especially striking when populations from Eastern Canada were compared with populations from Western Canada (phiST = 0.27%; P < 0.001), suggesting that a geographic reproductive barrier occurs in Central Canada. This barrier may be the consequence of a weak migration of insect vectors of C. resinifera due to reduced presence of hosts in the Canadian Great Plains, where extensive agriculture occurs. However, results from pairwise F(ST) matrix and phylogeny of haplotypes suggest that the barrier is not totally impenetrable because some gene flow occurred from the west and from the east in the Big River (Saskatchewan) population located in the middle of the Great Plains.  相似文献   

Minimally invasive patent ductus arteriosus occlusion in 5 dogs     

Borenstein N  Behr L  Chetboul V  Tessier D  Nicole A  Jacquet J  Carlos C  Retortillo J  Fayolle P  Pouchelon JL  Daniel P  Laborde F 《Veterinary surgery : VS》2004,33(4):309-313

OBJECTIVE: To report a technique for minimally invasive occlusion of patent ductus arteriosus (PDA) and outcome in 5 dogs. STUDY DESIGN: Clinical cases. Animals: Five, 4-6-month-old, dogs with PDA. MATERIALS AND METHODS: Titanium ligating clips were used for PDA closure in all dogs. Three dogs had video-enhanced mini-thoracotomy PDA occlusion. Two other dogs had thoracoscopic PDA occlusion using a custom-designed thoracoscopy clip applicator. RESULTS: Thoracoscopic PDA occlusion was successful in both dogs in which it was attempted. Complete PDA closure was achieved in 4 dogs. Three months after surgery, the largest dog had residual ductal flow that hemodynamically was insignificant. CONCLUSIONS: Although technically demanding, minimally invasive PDA occlusion is a safe and reliable technique in dogs. Preoperative measurement of the diameter of the PDA is crucial to determine if complete closure with metal clips can be achieved. CLINICAL RELEVANCE: Minimally invasive PDA occlusion should be considered as an alternative to occlusion via conventional thoracotomy.  相似文献   

Optical spectroscopy of individual single-walled carbon nanotubes of defined chiral structure     

Sfeir MY  Beetz T  Wang F  Huang L  Huang XM  Huang M  Hone J  O'Brien S  Misewich JA  Heinz TF  Wu L  Zhu Y  Brus LE 《Science (New York, N.Y.)》2006,312(5773):554-556

We simultaneously determined the physical structure and optical transition energies of individual single-walled carbon nanotubes by combining electron diffraction with Rayleigh scattering spectroscopy. These results test fundamental features of the excited electronic states of carbon nanotubes. We directly verified the systematic changes in transition energies of semiconducting nanotubes as a function of their chirality and observed predicted energy splittings of optical transitions in metallic nanotubes.  相似文献   

Atmospheric science. Fungi, weathering, and the emergence of animals     

Derry LA 《Science (New York, N.Y.)》2006,311(5766):1386-1387

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Copper metabolism and oxidative stress in chronic inflammatory and cholestatic liver diseases in dogs     

Spee B  Arends B  van den Ingh TS  Penning LC  Rothuizen J 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(5):1085-1092

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Infrared spectroscopy of comet 81P/Wild 2 samples returned by Stardust     

Keller LP  Bajt S  Baratta GA  Borg J  Bradley JP  Brownlee DE  Busemann H  Brucato JR  Burchell M  Colangeli L  d'Hendecourt L  Djouadi Z  Ferrini G  Flynn G  Franchi IA  Fries M  Grady MM  Graham GA  Grossemy F  Kearsley A  Matrajt G  Nakamura-Messenger K  Mennella V  Nittler L  Palumbo ME  Stadermann FJ  Tsou P  Rotundi A  Sandford SA  Snead C  Steele A  Wooden D  Zolensky M 《Science (New York, N.Y.)》2006,314(5806):1728-1731

Infrared spectra of material captured from comet 81P/Wild 2 by the Stardust spacecraft reveal indigenous aliphatic hydrocarbons similar to those in interplanetary dust particles thought to be derived from comets, but with longer chain lengths than those observed in the diffuse interstellar medium. Similarly, the Stardust samples contain abundant amorphous silicates in addition to crystalline silicates such as olivine and pyroxene. The presence of crystalline silicates in Wild 2 is consistent with mixing of solar system and interstellar matter. No hydrous silicates or carbonate minerals were detected, which suggests a lack of aqueous processing of Wild 2 dust.  相似文献   

Organics captured from comet 81P/Wild 2 by the Stardust spacecraft     

Sandford SA  Aléon J  Alexander CM  Araki T  Bajt S  Baratta GA  Borg J  Bradley JP  Brownlee DE  Brucato JR  Burchell MJ  Busemann H  Butterworth A  Clemett SJ  Cody G  Colangeli L  Cooper G  D'Hendecourt L  Djouadi Z  Dworkin JP  Ferrini G  Fleckenstein H  Flynn GJ  Franchi IA  Fries M  Gilles MK  Glavin DP  Gounelle M  Grossemy F  Jacobsen C  Keller LP  Kilcoyne AL  Leitner J  Matrajt G  Meibom A  Mennella V  Mostefaoui S  Nittler LR  Palumbo ME  Papanastassiou DA  Robert F  Rotundi A  Snead CJ  Spencer MK  Stadermann FJ  Steele A 《Science (New York, N.Y.)》2006,314(5806):1720-1724

Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in oxygen and nitrogen compared with meteoritic organics. Aromatic compounds are present, but the samples tend to be relatively poorer in aromatics than are meteorites and interplanetary dust particles. The presence of deuterium and nitrogen-15 excesses suggest that some organics have an interstellar/protostellar heritage. Although the variable extent of modification of these materials by impact capture is not yet fully constrained, a diverse suite of organic compounds is present and identifiable within the returned samples.  相似文献   

Cell signaling. Protein kinases seek close encounters with active genes     

Edmunds JW  Mahadevan LC 《Science (New York, N.Y.)》2006,313(5786):449-451

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Absence of detectable arsenate in DNA from arsenate-grown GFAJ-1 cells     

ML Reaves  S Sinha  JD Rabinowitz  L Kruglyak  RJ Redfield 《Science (New York, N.Y.)》2012,337(6093):470-473

A strain of Halomonas bacteria, GFAJ-1, has been claimed to be able to use arsenate as a nutrient when phosphate is limiting and to specifically incorporate arsenic into its DNA in place of phosphorus. However, we have found that arsenate does not contribute to growth of GFAJ-1 when phosphate is limiting and that DNA purified from cells grown with limiting phosphate and abundant arsenate does not exhibit the spontaneous hydrolysis expected of arsenate ester bonds. Furthermore, mass spectrometry showed that this DNA contains only trace amounts of free arsenate and no detectable covalently bound arsenate.  相似文献