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Prenatal ultrasonic diagnosis of a rare case of radial ray aplasia and crossed renal ectopy is described in an affected sibling of a family where the father and his son suffer from this rare syndrome. The prenatal diagnosis enabled early pregnancy termination. 相似文献
53.
Josué Israel García-López Francisco Zavala-García Emilio Olivares-Sáenz Guillermo Niño-Medina Norma Angélica Ruiz-Torres 《毒物与环境化学》2013,95(5-7):560-572
AbstractThe effects of suspensions of zinc oxide nanoparticles at concentrations between 100 and 500?mg L?1 on germination of Capsicum chinense seeds and vigor of plants were evaluated using a randomized complete design with four replications, resulting in increased germination and improved development of lengths of plumule and radicle. The activities of peroxidase, catalase and ascorbate peroxidase were determined, showing that at all concentrations the activities of the former two enzymes were increased, whereas the activity of the latter was reduced at 500?mg L?1. Pretreatments of seeds with ZnO nanoparticles can improve germination and development of seedlings and the activities of antioxidant enzymes. 相似文献
54.
Photosynthetic properties of the common red algaGracilaria conferta, collected from the eastern Mediterranean Sea were investigated in 1989, in order to begin evaluating its adaptative strategies with regard to the inorganic carbon composition of seawater, and to test whether the alleged C4 photosynthesis of anotherGracilaria species is common within the genus. Net photosynthetic rates ofG. conferta were, under ambient conditions of inorganic carbon (ca. 10µM, CO2 and 2.2 mM HCO
3
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), not sensitive to O2 over the range 10 to 300µM, and the CO2 compensation point was low (ca. 0.005µM). Ribulose-1,5-bisphosphate carboxylase/oxygenase was the major carboxylating enzyme, with a crude extract activity of 175µmol CO2 g–1 fresh wt h–1 while phosphoenolpyruvate carboxylase and phosphoenolpyruvate carboxykinase were present at 70 and 20%, respectively, of that activity. No activities of the decarboxylases NAD-and NADP-malic enzyme could be detected. The14C pulse-chase incorporation pattern showed thatG. conferta fixes inorganic carbon via the photosynthetic carbon reduction cycle only, with no evidence for photosynthetic C4 acid metabolism. Photosynthesis at the natural seawater pH of 8.2 was, at 25°C and saturating light, saturated at the ambient inorganic carbon concentration of 2.5 mM. It is proposed that, under ambient inorganic carbon conditions, a CO2 concentrating system other than C4 metabolism provides an internal CO2 concentration sufficient to suppress the O2 effect on ribulose-1,5-bisphosphate carboxylase/oxygenase and, thus, on photorespiration, in a medium where the external free CO2 concentration is lower than theK
m(CO2) of the carboxylating enzyme. Since inorganic carbon, under natural saturating light conditions, seems not to be a limiting factor for photosynthesis ofG. conferta, it likely follows that other nutrients limit the growth of this alga in nature. 相似文献
55.
The impact of mussel farms on the benthic environment was investigated using free-living nematode assemblages as indicators of environmental condition of the Enseada do Brito, a shallow embayment in South Brazil. The studied area is located at the State of Santa Catarina, responsible for 90% of the production of mussel farmed in the country. Samplings were carried out quarterly, from July 2004 to May 2005, below mussel ropes and at control sites located 300 m apart from the longlines. The results suggested that the mussel culture changed ecological functioning of the benthic environment at studied coastal embayment. The intense organic loads due to the biodeposition of the mussel farms, which had been in production for more than 10 years, have turned fine and well-sorted sand bottoms into a muddy deposit with significantly higher total organic content than the control. The number of nematode genera, diversity, dominance and trophic diversity were significantly lower under the mussel farms than at the control sites. The mussel farms biodeposition had also affected the temporal variability of nematode assemblages, which was detected only for samples at the control sites. The low depth and environmental energy, together with the age of the farms, were probably responsible for the observed changes in the nematode assemblages. 相似文献
56.
The new recommendations of WHO and EC for legislation in Europe and other countries concerning non-ionizing radiation (NIR)
health and safety include exposure limits that are very debatable. ICNIRP Guidelines propose exposure limits for electromagnetic
fields in the frequency range up to 300 GHz based on short-term exposures and on thermal effects. The new EC proposal for
optical and laser safety legislation includes classification of sources of radiation—both lasers and other optical sources,
but not requirements for the methodology of classification. On the other hand, many new requirements have been set by the
WHO publication “Model Legislation for EMF Protection” concerning the responsibilities in the field of EMF health and safety.
Many specialists in the field of developing exposure limits have positions very far away from the proposed of the ICNIRP Guidelines
philosophy. The results are different approaches in developing standards and exposure limits, and differences more than 100
times in maximal permissible levels. We, the Bulgarian Program Committee on NIR, try to organize working groups and discuss
different philosophy for developing exposure limits for more than 10 years. This paper exposes our position in this area. 相似文献
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Electromagnetic field sources used for communication always have been subject of serious interest. There are many publications
concerning exposure and risk assessment of the working in such environment. Results of epidemiological study performed in
Bulgaria in the 1990's show exceeding of the maximal permissible values especially in radio stations for the personnel in
24 h working shift [Israel et al. (1992). Study of the electromagnetic in its influence on personnel working in radio and
TV stations, Report, National Centre of Hygiene, Medical Ecology and Nutrition; Israel and Tomov (2001). Epidemiological study
of the effects of radiofrequency radiation on operators in radio, TV and relay stations, Proceeding of the Eastern European
Regional Meeting and Workshop “Measurements and Criteria for Standard Harmonization in the field of EMF Exposure” and WHO
EMF Standards Harmonization Meeting, Varna, Bulgaria, 28 April—3 May, 2001, pp.145–153]. In the last years the situation is
strongly influenced by the development of the technology which leads to changes in equipment in radio and TV stations, using
lower power, facilitate the working regime. The paper presents data of exposure assessment of different professional groups
in selected radio and TV stations. Assessment is being performed on basis of EMF parameters values and energetic load calculations
according to the national legislation. Data are compared with the results of previous investigation to evaluate the new situation
in this branch. Exposure levels are much lower than those in the previous study, and lower compared to the exposure limits,
as well [Israel et al. (1992). Study of the electromagnetic in its influence on personnel working in radio and TV stations,
Report, National Centre of Hygiene, Medical Ecology and Nutrition; Israel and Tomov (2001). Epidemiological study of the effects
of radiofrequency radiation on operators in radio, TV and relay stations, Proceeding of the Eastern European Regional Meeting
and␣Workshop “Measurements and Criteria for Standard Harmonization in the field of EMF Exposure” and WHO EMF Standards Harmonization
Meeting, Varna, Bulgaria, 28 April—3 May, 2001, pp.145–153]. 相似文献
60.