216 research outputs found
Alkylation of phenazine with N-chloroamines
No full text2-Alkyl sbstitued phenazines are obtained from phenazine and long chain alkyl N-chloroamines in conc. sulfuric acid under the condition of Hofmann-Loffler-Frytag reaction and from phenazione an aliphatic substrate and N,N-dialkyl-N-chloroamines in conc. sulfuric acid. Under these conditions the reactive species was the diprotonated form of phenazine (pKa2 = -5.1)
Application of Electrical Resistivity Ground Imaging (ERGI) to aid the Acid Mine Drainage (AMD) evaluation in the Rio Marina mining district (Elba Island)
No full textThe Rio Marina mining district (Elba island) was one of the greatest Italian iron ore and was exploited till 1981. Nowadays it is used as an excursion site and it is famous all around the world for its hematite-pyrite mineralogical samples and for its multi-colour acid pools. These pools are related to Acid Mining Drainage (AMD) process that occur in the sulfide-mining area. The effect of open-pit mining and other mining-related activities is that sulfides, previously isolated from the atmosphere, are exposed to oxygen. The oxidation of sulfides acidifies the flowing waters that leach ore minerals and dissolve elements such as arsenic, copper, manganese, iron, lead and zinc. This process leads to environmental pollution. The Rio Marina mining district is currently object of a geo-environmental characterization to assess hazard and persistence of the AMD process (Servida et al. 2006). In addition to investigations on surface waters, terrains and topographic evolution of the mining site, a geo-environmental model aiming to AMD evaluation requires the determination of: 1) waste rock thickness, to evaluate the amount of sulfuric acid that could be produced and the content of heavy metals that could be leached from terrains; 2) distribution of sulfides in the waste deposits; 3) distribution of the water-rich zones in waste deposits. The aim of this work is to supply these data by means of 2-D Electrical Resistivity Ground Imaging (ERGI) techniques. The pilot-study was performed on the Antenna plains, which represent one of the waste disposals of Rio Marina district. This area was chosen since 3-D topographical modelling, field survey and bibliographic data show no certain information concerning the thickness of the waste deposits. The following procedure was adopted: 1)acquisition of five ERGI profiles over the Antenna plains and identification of bodies showing homogeneous distribution of electrical resistivity. ERGI profiles were acquired by means of Wenner-Schlumberger array with 44 electrodes, with electrodes-spacing ranging from 3.0 to 5.0 m (maximum depth of investigation = 40.0 m). Profiles were acquired on a square grid in order to investigate the 3-D features of the subsurface; 2) direct-calibration of electrical resistivity class-values of bedrock (60-150 Ohm*m) and hematite-pyrite mineralized ore bodies (10-30 Ohm*m) by acquisition of 1 ERGI profile (Wenner-Schlumberger array; 30 electrodes, electrode-spacing = 2,5 m) located on an exposed quarry bench in the proximity of the Antenna plains; 3) interpretation of electrical resistivity distribution obtained by ERGI profiles by the light of a) the model of subsurface from 1954-1979 topographic and mining maps, b) knowledge of ore-geological model of the mining area, c) electrical resistivity obtained from the direct-calibration made on the outcropping analogue materials, d) physical and chemical properties of surface waters and terrains;
4) 3-D interpolation by geostatistical analysis (kriging) of the boundary between the electrical resistivity bodies correlated to bedrock-ore bodies complex and the hypothesized waste deposits. The results show that: 1) Antenna plains are composed by waste deposits with a maximum depth of about 25.0 m. These data confirm that Antenna was an old open-pit used as a mine-waste dump; 2) waste deposits have highly-conductive homogeneous electrical properties (<10 Ohm*m) and, consequently, they could have an homogeneous water-content and chemical composition. The low resistivity value is due to the high conductivity of groundwater (average groundwater conductivity: 7.54 mS/cm = 1.3 Ohm*m) and the occurrence of clay minerals produced by in-situ weathering of bedrock and debris; 3) bedrock has highly-conductive anomalies (10-30 Ohm*m) that, from their geometry, position and electrical resistivity values, could be interpreted as hematite-pyrite mineralized ore bodies
Nucleophilic character of alkyl radicals. Part 15. Selective homolytic alkylation of quinoxaline by N-chloro-amines; influence of medium acidity
No full textSelective homolytic alkylation of protonated quinoxaline has been achieved by using an alkyl derivative with N-chlorodialkylamine as radical source. The method shows great synthetic potential and can also be used for other heteroaromatic bases. A free-radical chain process involving amine radical cations is suggested to explain the clean reaction. Positional selectivity is strongly affected by the medium acidity, and a correlation between the π-electron density of mono- and di-protonated quinoxaline and the substitution orientation is found, in agreement with the nucleophilic character of the alkyl radicals
Engine/Transmission Matching
No full textThis chapter deals with the forecasting of vehicle performance on the road, according to the installed engine.
It begins with Section 1, which shows the calculation of the resistance to motion, that is, the forces that the vehicle must
overcome to advance on flat roads and uphill. The calculation excludes accidental resistance in curves because it is not
essential for predicting the behavior of the vehicle on the road. Section 2 begins with the power characteristic, the forecast
by traction–speed and power –speed diagrams, calculation of gear ratios, and then passing to the limits to the estimated
acceleration, feature consumption, and distance. This chapter concludes with a section on the drivability of the vehicle,
and sets out the advantages of four-wheel-drive vehicles
A familial balanced inverted insertion ins(15)(q15q13q11.2) producing Prader-Willi syndrome, Angelman syndrome and duplication of 15q11.2-q13 in a single family: importance of differentiation from a paracentric inversion
No full textWe reascertained a family in which first cousins were affected by Angelman syndrome and Prader-Willi syndrome. A paracentric inversion of 15q11-q15 had previously been reported in this family but we show, using fluorescence in situ hybridization (FISH), that the rearrangement segregating in this family is not a paracentric inversion but an inverted intrachromosomal insertion, inv ins(15)(q15q13q11.2). We also describe a further recombinant resulting in a maternal duplication of the Prader-Willi/Angelman critical region. This family illustrates the importance of distinguishing paracentric inversions from intrachromosomal insertions
An Audit of a UNESCO World Heritage site - the Royal Mile, Edinburgh:a preliminary search for authenticity
No full textCharacterization of breakpoints in the GABRG3 and TSPY genes in a family with a t(Y;15)(p11.2;q12)
No full textWe report the clinical, cytogenetic, and molecular findings in a family in which a t(Y;15)(p11.2;q12) is segregating. The Y chromosome breakpoint disrupts the DYZ5 sequence containing the TSPY genes that are exclusively expressed in the testes while the chromosome 15 breakpoint is within the GABRG3 gene. The father and his son who both carried the balanced form of the translocation are clinically normal. A daughter who carried the der Y had the clinical features of Prader-Willi syndrome while a son who carries the der 15 has mild developmental delay and hypogonadism. The relationship of the translocation to the clinical phenotypes is discussed
De novo deletions and duplications detected by array CGH: a study of parental origin in relation to mechanisms of formation and size of imbalance
No full textWe report a large series of 173 patients with physical and/or neurological abnormalities and a de novo imbalance identified by array CGH. Breakpoint intervals were screened for the presence of low copy repeats (LCRs) to distinguish between rearrangements formed by non-allelic homologous recombination (NAHR) and rearrangements formed by other mechanisms. We identified significant differences in size and parental origin between the LCR-mediated and non-LCR groups. Non-LCR imbalances were evenly distributed among the four size intervals we defined, whereas LCR-mediated rearrangements had a narrow size distribution, predominantly between 1 and 5?Mb (P=0.001). Among the LCR-mediated rearrangements there were equal numbers of maternally and paternally derived cases. In contrast, for the non-LCR rearrangements there was a significant excess of paternal cases (P=0.024) over a wide size range including below 1?Mb. Our results provide novel evidence that unbalanced chromosome rearrangements are not only more frequent in males, but may also arise through different mechanisms than those seen in females. Although the paternal imbalances identified in our study are evenly distributed throughout the four size groups, there are very few maternal imbalances either <1?Mb or >10?Mb. Furthermore, a lower proportion of paternal imbalances are LCR mediated (13/71) compared with the maternal imbalances (12/30). We hypothesise that imbalances of maternal origin arise predominantly through NAHR during meiosis, while the majority of imbalances of paternal origin arise through male-specific mechanisms other than NAHR. Our data suggest that mitotic mechanisms could be important for the formation of chromosome imbalances; however, we found no association with increased paternal age
Unusual (CGG)n expansion and recombination in a family with fragile X and DiGeorge syndrome
No full textIn a fragile X family referred for prenatal diagnosis, the female fetus did not inherit the full fragile X mutation from her mother, but an unexpected expansion within the normal range of CGG repeats from 29 to 39 was observed in the paternal X chromosome. Also, a rare recombination between DXS548 and FRAXAC1 was recorded in the maternal meiosis. Follow up of the neonate confirmed the same DNA genotype as in the CVS, but the child died of DiGeorge syndrome after four days and was subsequently found to carry a microdeletion of chromosome 22 using probe cEO. It is suggested that in this family the deletion of chromosome 22 is likely to be a chance event but the rare recombinant and the fragile X mutation might be causally relate
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