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排序方式: 共有186条查询结果,搜索用时 31 毫秒
61.
Maltaris T Beckmann MW Binder H Mueller A Hoffmann I Koelbl H Dittrich R 《Reproduction (Cambridge, England)》2007,133(2):503-509
This prospective study compares the effect of a GnRH agonist on the number of follicles in different developmental stages in cryopreserved human ovarian grafts transplanted into gonadotropin-stimulated or not stimulated severe combined immunodeficient mice (SCID mice). Human ovarian tissue from seven patients was cryopreserved with an open-freezing system and xenotransplanted in SCID mice. The SCID mice were then treated according to different stimulation protocols. The survival of the tissue after cryopreservation was examined by LIVE/DEAD viability staining or transplanted in the neck muscle of 41 SCID mice. Development of follicles, estradiol production, vaginal cytology, and uterus weight were assessed after 15 weeks with or without gonadotropin stimulation. Viable follicles were detected in all frozen/thawed specimens using the LIVE/DEAD assay. Triptorelin, a GnRH agonist, caused a significant reduction of follicles in all developmental stages in the non-gonadotropin-stimulated animals (P<0.001). In gonadotropin-stimulated animals, GnRH agonist treatment has no significant effect on primordial, primary and preantral follicle count, whereas the antral follicles were significantly fewer (P = 0.03). The GnRH agonist treatment is not able to prevent the primordial follicle depletion after the xenografting of ovarian tissue in SCID mice with or without gonadotropin stimulation. Furthermore, it causes an additional loss of follicles if administered during the critical neovascularization period after the transplantation. 相似文献
62.
The perceptual and physiological characteristics of the speech of a nine year old child who suffered a basilar artery stroke at the age of five years were investigated using a battery of perceptual and physiological instrumental measures. Perceptual tests administered included the Frenchay Dysarthria Assessment, a perceptual analysis of a speech sample based on a reading of the Grandfather Passage and a phonetic intelligibility test. Instrumental procedures included: spirometric and kinematic analysis of speech breathing; electroglottographic evaluation of laryngeal function, nasometric assessment of velopharyngeal function and evaluation of lip and tongue function using pressure transducers. Physiological assessment indicated the most severe deficits to be in the respiratory and velopharyngeal sub-systems with significant deficits in the articulatory sub-system, all of which resulted in severely reduced intelligibility. These results were compared and contrasted with the subject's performance on the perceptual assessment battery. In a number of instances the physiological assessments were able to identify deficits in the functioning of components of the speech production apparatus either not evidenced by the perceptual assessments or where the findings of the various perceptual assessments were contradictory. The resulting comprehensive profile of the child's dysarthria demonstrated the value of using an assessment battery comprised of both physiological and perceptual methods. In particular, the need to include instrumental analysis of the functioning of the various subcomponents of the speech production apparatus in the assessment battery when defining the treatment priorities for children with acquired dysarthria is highlighted. Treatment priorities determined on the basis of both the perceptual and physiological assessments for the present CVA case are discussed. 相似文献
63.
Eleftheria Siachalou Theodoros Samaras Christos Koukourlis Stavros Panas 《Electrical Engineering (Archiv fur Elektrotechnik)》2006,89(2):107-116
Beam tilting of a mobile Base Station (BS), as a technique that limits the transmitted signals to each cell, introduces a
way of increasing the system bit rate over a wider range than that without beam tilting. In this paper, the general approach
of a BS antenna is being evaluated giving the system's response for different half power beamwidths (HPBW) and different types
of propagation environments. The critical rate of the system versus the level of diffuse reflection, the communication distance,
the excess distance and the height of the BS antenna are being examined. 相似文献
64.
65.
The politics and science behind GMO acceptance 总被引:1,自引:0,他引:1
Varzakas TH Arvanitoyannis IS Baltas H 《Critical reviews in food science and nutrition》2007,47(4):335-361
The question of nutritional quality has arisen in the International Community over the last few years along with other important issues such as population aging, multipopulation societies, and political conflicts. The nutritional issue is questioned both quantitatively and qualitatively. It is well known that the planet faces enormous problems with food that is available. Nowadays 20% of the population consumes approximately 80% of the produced energy and natural resources. During the last 15 years, a series of food scares and crises (BSE, dioxin, foot and mouth disease, bird flu) have seriously undermined public confidence in food producers and operators and their capacity to produce safe food. As a result, food safety has become a top priority of the European legislative authorities. Genetically Modified Organisms (GMOs) is the new food safety concern which despite the intense reactions from Non Governmental Organizations and consumer organizations have entered our lives with inadequate legislative measures to protect consumers from their consumption. The GMO issue will be the issue for discussion in the long run not only for the European Community but also for the international community as far as scientific, economical, political, ideological, ethical, and human issues are concerned. These issues are discussed in this paper along with a case of study of GM fish. 相似文献
66.
Samaras T Christ A Klingenböck A Kuster N 《IEEE transactions on bio-medical engineering》2007,54(3):492-496
This paper investigates the temperature rise in a 1-D layered tissue model, which is irradiated with nonionizing radiation. Of the numerous tissue configurations that correspond to realistic body trunk and limb representations, only those are examined which maximize the averaged specific absorption rate (SAR). The results show that the old IEEE standard on safety was more conservative in terms of temperature rise than the Non-Ionizing Radiation Protection guidelines. They also indicate that the removal of heat exchange from the skin surface can induce a significant temperature rise in it, which is, however, mostly due to imposing the adiabatic conditions themselves, rather than the electromagnetic energy absorption. 相似文献
67.
Theodoros Adamakos Stelios PetridisAristidis Iliopoulos 《Journal of Constructional Steel Research》2011,67(3):462-470
A new way of modeling steel composite bridges has been presented by Vayas et al. (in press, 2010)
[3.] and [4.]. The proposed model is based on the representation of steel I-girders by equivalent trusses. The concrete slab is suitably represented by a set of bar elements, and the bearings by appropriate springs. Diaphragms and stiffeners may also be taken into account. In comparison to the grillage model, which is usually used for the analysis of bridges, the proposed three-dimensional model allows a more reliable prediction of deformations, internal forces, and stresses. Curved bridges display unique behavior characteristics, and for this reason a grillage analysis is not always suitable. The new way of modeling composite bridges, using a spatial system of beam-like structural elements, is applied in this paper for the modeling of curved composite bridges. Worked examples are provided to illustrate the set-up procedure of the proposed modeling and to compare its results with those of corresponding finite element models. 相似文献
68.
Theodoros A. Papadopoulos Jens Meyer Hong Li Zelei Guan Antoine Kahn Jean‐Luc Brédas 《Advanced functional materials》2013,23(48):6091-6099
A combination of density functional theory and experimental measurements via ultraviolet and X‐ray photoelectron spectroscopies is used to explore the nature of the interface between the stoichiometric molybdenum trioxide (MoO3) or its under‐stoichiometric counterpart with oxygen vacancies, and an organic hole‐transport layer represented by 4,4′‐N,N′‐dicarbazole‐biphenyl (CBP). Upon adsorption of CBP, special attention is paid to i) the appearance of gap states and the reduction of the molybdenum oxide surface, and ii) the evolution of the work function. Very good agreement is found between theory and experiment. The near alignment of the CBP highest occupied molecular orbital with the Fermi level and the conduction band edge of molybdenum oxide points to facile hole collection or injection. 相似文献
69.
The application of green roofs on urban buildings is considered to have a positive impact on their thermal behaviour and local microclimatic conditions. According to the literature, their ability for attenuation of storm water run-off as well as their contribution to the building's thermal protection is among the most important benefits of this technique. However, despite the development of computer models that can assist towards analysing the nature of their behaviour, there is still a relative gap in measured data representing long-term period thermal performance. In this paper, the results of a long-term experimental analysis are presented, which attempt to identify the thermal behaviour of a green roof in comparison with a bare flat roof. The results show that in Mediterranean countries, a green roof can contribute substantially to building's energy conservation mainly during the warm period of the year, while its influence during the cold period is negligible. 相似文献
70.
Theodoros Tzamkiozis Leonidas Ntziachristos Athanasios Mamakos Georgios Fontaras Zissis Samaras 《Aerosol science and technology》2013,47(5):587-595
This article examines the effect of biodiesel blends on the exhaust aerosol from a Euro 3 passenger car. Five different feedstock oils (soybean, palm, sunflower, rapeseed, and used frying oil) were used to produce fuels with 10% vol. content in biodiesel (B10). Use of the B10 blends led to a systematic reduction of PM mass emissions in the range of ~9% (rapeseed) to 23% (used frying oil) on average. The combination of particle size distributions based on the aerodynamic and the mobility diameters led to the estimation of the fractal dimension (DF) for non-volatile particles. This was found to range from 2.52 for the baseline (fossil) fuel to 2.62 for the palm oil blend, suggesting that biodiesel can affect the particle morphology, even at this low blending ratio. The differences were statistically significant. The increase of the DF is translated to more compact particle structure, which in turn denotes lower specific surface area. The volatile fraction of PM lies within a range of 1–9% when fossil diesel fuel is employed. Use of palm, sunflower and rapeseed B10 blends results to PM that contain up to 28% volatile particulate mass. The higher emissions of volatile components together with the lower specific area of non-volatile particles, promotes the formation of volatile particles, especially at high speed conditions. This increases the total particle population under motorway driving by up to three times over the baseline levels. 相似文献