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排序方式: 共有640条查询结果,搜索用时 15 毫秒
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Ion Tcacencu MD ; Bengt Carlsöö MD PhD ; Pontus Stierna MD PhD 《Wound repair and regeneration》2005,13(3):341-349
We determined the origin of new cartilage and new bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) at the site of cricoid cartilage defects in rabbits randomly divided into eight groups. The cricoid cartilage was split vertically along the anterior midline and a strip was excised from the anterior part of the cricoid cartilage in all rabbits. The perichondrium from the anterior part of the cricoid cartilage was trimmed off in four groups; two groups treated with rhBMP-2 and two control groups. In four other groups, the anterior perichondrium was detached and used as a flap with two groups treated with rhBMP-2 and two groups serving as controls. The rabbits were killed 1 week or 4 weeks after surgery. The larynges were removed, fixed and sectioned, and the sections were stained for light microscopy using various cytochemical and immunological techniques. New cartilage was only present close to the host perichondrium adherent to cricoid cartilage in rabbits treated with rhBMP-2. New bone was present 4 weeks after surgery, although calcified matrix and alkaline phosphatase activity could be detected at the site of cricoid defects as early as 1 week after surgery. The cell proliferation marker Ki-67 was strongly expressed in granulation tissue and bone marrow, and it was moderately expressed in muscles adjacent to the cricoid cartilage in rhBMP-2-treated specimens. BMP receptors were strongly expressed in cartilage and moderately expressed in adjacent muscles. We conclude that new cartilage originates from the mesenchymal progenitor cells of host perichondrium adherent to cricoid cartilage in rabbits treated with rhBMP-2. New bone may originate from local muscle. 相似文献
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Livia Maria Ionescu Ion Petrea Ingrid Ionescu Bujor Ioana Demetrescu 《Macromolecular chemistry and physics.》1983,184(5):1005-1015
Light scattering measurements from aqueous solutions for two samples of poly(acrylamide-co-maleic anhydride) in the presence of salt are conducted. One of the samples exhibits a negative initial slope and a minimum in the plot of the conventional reciprocal scattered intensity function of sin2 (θ/2). The explanation for this anomaly is a large optical anisotropy of the segment. A correction for this effect of segmental anisotropy is made. The behaviour of the other sample of this copolymer is typical for a polyelectrolyte. By analysing the disymmetry of the scattered light, the influence of the salt concentration on the polyion is evidenced by the determination of the macromolecular dimensions. Light scattering data allow the evaluation of the Mark-Kuhn-Houwink exponent a for various degrees of dissociation of the polyion; a correlation between the variation of a and the shape of the macromolecule is observed. 相似文献
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Utilizing solid wastes and industrial by-products as a partial replacement for raw materials has become an acceptable practice among researchers and scientists in the civil engineering field. Sawdust and wood shavings are not an exception; they are being used in concrete as a partial or total replacement for some of its constituents. The main goal of this research is to establish a relation between destructive and non-destructive testing for concrete containing wood shavings as a partial replacement of sand (woodcrete). With this type of material existing, thus the need to understand the behavior of such material becomes urgent and evokes the need to ease the process of the assessment and the evaluation of such materials and therefore provide more understanding of its behavior. In addition to the conventional concrete mix, five mixes of woodcrete were made by replacing fine aggregate by volume with wood shavings at different replacement levels varied from 5% to 50%. Cubic samples were tested at the age of 90 days using nondestructive tests (NDT), namely, rebound hammer test and ultrasonic pulse velocity test. Then, the specimens were tested using a conventional compressive test using a universal compression testing machine. Statistical analysis was performed to establish empirical relations between destructive and non-destructive results. The dynamic modulus of elasticity was calculated, and some formulas to estimate the (compressive) strength of woodcrete using NDT results were proposed and tested against experimental results and showed acceptable results. 相似文献
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Ion Udroiu Antonio Antoccia Antonella Sgura 《International journal of radiation biology》2017,93(3):261-269
Purpose: To investigate the genotoxic effects of prenatal X-irradiation in mice and the possible presence of late genomic instability.Materials and methods: Pregnant mice were exposed to 0, 1 or 2?Gy at embryonic day 11.5. Blood smears were obtained from pups at birth and on post-natal day 11, 21, 42 and 140. Hematological data (diameter of erythrocytes, percentage of reticulocytes and Granulocyte-to-Lymphocyte ratio [GLR]) and genotoxicity (micronucleated erythrocytes, micronucleated reticulocytes, CREST-positive and negative micronuclei) were assessed.Results: Prenatal irradiation caused perinatal reticulocytosis (which ended on postnatal day 11) and a dose-dependent increase of GLR (indicative of myeloid skewing) on postnatal days 42 and 140. Two temporally distinct genotoxic effects were observed: an early, acute damage (still detectable at birth and soon after) and a late, long-term damage.Conclusions: Increases in micronuclei frequencies and GLR observed from day 42 on are both ascribable to DNA damage. Time of appearance of this late effect may be linked to the shift of hematopoiesis from spleen to bone marrow and to cell-extrinsic factor such as the microenvironment. This study confirms that ionizing radiation can induce long-term genotoxic effects in the hematopoietic system and shows that prenatal irradiation determines genomic instability in blood-forming tissues of adult mice. 相似文献
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The aim of this cross-sectional study was to examine the association of supernatural beliefs and sense of coherence with death anxiety and death depression in a Romanian sample of cancer patients. We found support for the terror management theory worldview defence hypothesis postulating the presence of a curvilinear relation between death anxiety and supernatural beliefs among cancer patients. Results conformed to an inverted U-shape quadratic regression, indicating that cancer patients who scored moderately on supernatural beliefs were afraid of death the most, while death anxiety was lowest for the extreme atheists and extreme believers in supernatural entities. 相似文献
9.
Chon Fu Lio Hou Hon Cheong Chin Ion Lei Iek Long Lo Chong Lam Iek Hou Leong 《World Journal of Clinical Cases》2020,8(13):2674-2678
Macao, a special administrative region (SAR) of the People’s Republic of China, is located in southern China and shares the border with mainland China. It is the most densely populated region in the world, with a population of 667400 and a total land area of 32.9 square kilometers in 2019. Since the first case diagnosed on January 22, 2020, there was a total of 45 laboratory-confirmed coronavirus disease 2019 (COVID-19) cases in Macao, of which 43 patients (96%) were imported cases. To date, all patients had been discharged successfully from Centro Hospitalar Conde de São Januário, a designated hospital to manage all COVID-19 patients in Macao. Eventually, no patient died, and no local community outbreak was noted. This opinion review describes the underlying factors that could have contributed to the successful experience in Macao SAR, China, which include the following: (1) Early implementation of containment measures; (2) Large-scale quarantine using hotel rooms to reduce the risk of a local outbreak; and (3) Multidisciplinary co-operation and transparency of information to the public. Although the successful experience in Macao SAR, China, may not be generalized to other regions, it should not be unreasonable to be well prepared with sufficient logistic support to conduct timely containment and early detection of episodic cases to prevent the backsliding of COVID-19 outbreak. 相似文献
10.
Tahir Khan Peter Danyi On Topaz Asghar Ali Ion S. Jovin 《The International journal of angiology》2013,22(4):251-254
Spontaneous coronary artery dissection is a rare but increasingly recognized cause of acute myocardial ischemia in young adults, especially in women. We report a case of spontaneous coronary dissection in a young healthy man who was also a carrier of the factor V Leiden gene mutation. 相似文献