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A cribriform plate, a perpendicular plate, and two lateral masses are major components of the ethmoid bone of mammals. Notwithstanding the noticeable bone, virtually sitting in the center of the skull, extensive modifications of the skull of modern cetaceans, especially odontocetes (toothed whales), and the lack of clarity as to what characteristics delimit each element of the ethmoid has made the problem of the nature of the cetacean ethmoid more complicated and elusive than in other, less modified mammals. Furthermore, contention as to whether a perpendicular plate of the ethmoid, or the mesethmoid, exists in all mammals including cetaceans has remained unsettled. In odontocetes, the mesethmoid has been variably identified not only as the osseous nasal septum but also as the mediodorsal region of the posterior wall of the nasal passage below the nasals, as a mass of bone encased by the vomer in front of the osseous nasal cavity at the base of the rostrum, and as a combination of some portions mentioned above. The presence or absence of the mesethmoid in various groups of mammals has attracted the attention of some biologists, and here, I demonstrate that cetaceans have no mesethmoid. The close inspection of the ontogenetic changes of the basicranial elements in cetaceans reveals that a mass of bone ensheathed by the vomer in front, or at the level of the osseous nasal cavity is actually the presphenoid. It is highly likely that in odontocetes the posterior wall of the nasal passages below the nasals consists of the combination of the frontal, the imperforated cribriform plate, the paired ectethmoids, and the vomer, the latter three of which partially concealing the presphenoid dorsally and laterally as the ontogeny proceeds. In contrast, mysticetes clearly display ethmoturbinates and a cribriform plate, which are morphologically similar to those in terrestrial mammals. J. Morphol. 277:1661–1674, 2016. © 2016 Wiley Periodicals, Inc.  相似文献   

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The case of a 56-year-old female with coexisting aspergillosis and squamous-cell carcinoma in the maxillary sinus is reported. The diagnosis was established by cytologic study of washings of the sinus before and after admission and was confirmed by exploratory antrotomy. To our knowledge, this is the first case in which the coexistence of fungus and neoplasm in the paranasal sinus was established by preoperative cytologic diagnosis.  相似文献   

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Summary The absorption of radium from solution, by plants, has been compared with that of calcium, active strontium being used as a label for the calcium. It was found that radium was preferentially retained by the roots and discriminated against in passage to the shoots. However, the uptake and distribution of radium was influenced by ethylenediaminetetra acetic acid (EDTA) and citrate at the concentrations employed in water culture media to keep iron in solution. There was little discrimination against radium after plants had grown for a week in active nutrient solution when EDTA was present, but in the presence of citrate radium moved less rapidly by a factor of about 0.3. In the early stages of treatment, less than a day, the results with citrate were comparable with those of EDTA, whence it is inferred that the decrease in transfer to the shoots is dependent upon the relative rates at which the two complexes decompose.  相似文献   

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1. The isotopes (45)Ca and (224)Ra were administered simultaneously, both orally and intravenously, to two pairs of cows. 2. The first pair of animals received large doses of (224)Ra and (45)Ca, which produced clinical and metabolic disturbances. 3. The second pair of animals received much smaller doses and showed no clinical disturbances. The mean recoveries in these animals of (45)Ca and (224)Ra in the 8 days after the oral administration were respectively: from faeces, 63.2 and 103.8%; from urine, 0.26 and 0.44%; from milk, 15.8 and 0.35% of the dose; and in the 8 days after intravenous administration: from faeces, 20.5 and 36.5%; from urine, 1.56 and 17.6%; from milk, 49.3 and 11.8% of the dose. 4. Calculation of discrimination factors shows that absorptive discrimination played the most important part in the overall discrimination between the calcium and radium in their passage from diet to milk, but that mammary discrimination plays a more important role than in the overall discrimination between calcium and strontium or barium. 5. In its treatment by the kidney radium is more like strontium than barium, but radium is actively secreted by the gut in the same way as barium. 6. In its skeletal metabolism radium is indistinguishable from calcium and strontium except in its rate of resorption, which is similar to that of barium.  相似文献   

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Summary It has been demonstrated that radium radiation causes a decrease in concentration of -SH and -S.S- of glutathione in aqueous solution. From this and the results of experiments with living organisms it is concluded that the cell proliferation retarding action of radium in weak non-destructive amounts, is largely due to the throwing out of commission of sulfhydryl, the naturally occurring chemical stimulus to growth by increase in cell number. It is further probable that this is enhanced by the production, through the action of radium on the -S. S- linkage, of sub-oxidized sulfur derivatives, which have been shown to be retardative of cell multiplication.  相似文献   

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