384 research outputs found
Tripraseodymium pentairon(III) dodecaoxide, Pr3Fe5O12: a synchrotron radiation study
The title compound, pentairon tripraseodymium dodecaoxide (PrIG), has an iron garnet structure. There are two Fe site symmetries. One of the Fe atoms is coordinated by six O atoms, forming a slightly distorted octahedron, and has site symmetry. The other Fe atom is coordinated by four O atoms, forming a slightly distorted tetrahedron, and has site symmetry. FeO6 octahedra and FeO4 tetrahedra are linked together by corners. The Pr atom is coordinated by eight O atoms, forming a distorted dodecahedron, and has 222 site symmetry. The O atoms occupy the general positions
Trineodymium(III) pentairon(III) dodecaoxide, Nd3Fe5O12
The title compound, Nd3Fe5O12 (NdIG), has an iron garnet structure. One of the Fe atoms is coordinated by six O atoms in a slightly distorted octahedral geometry and has site symmetry. The other Fe atom is coordinated by four O atoms in a slightly distorted tetrahedral geometry and has site symmetry. The FeO6 octahedron and FeO4 tetrahedron are linked together by corners. The Nd atom is coordinated by eight O atoms in a distorted dodecahedral geometry and has 222 site symmetry. The O atoms occupy general positions
Lineage-Specific Duplication and Loss of Pepsinogen Genes in Hominoid Evolution
Fourteen different pepsinogen-A cDNAs and one pepsinogen-C cDNA have been cloned from gastric mucosa of the orangutan, Pongo pygmaeus. Encoded pepsinogens A were classified into two groups, i.e., types A1 and A2, which are different in acidic character. The occurrence of 9 and 5 alleles of A1 and A2 genes (at least 5 and 3 loci), respectively was anticipated. Respective orthologous genes are present in the chimpanzee genome although their copy numbers are much smaller than those of the orangutan genes. Only A1 genes are present in the human probably due to the loss of the A2 gene. Molecular phylogenetic analyses showed that A1 and A2 genes diverged before the speciation of great hominoids. Further reduplications of respective genes occurred several times in the orangutan lineage, with much higher frequencies than those occurred in the chimpanzee and human lineages. The rates of non-synonymous substitutions were higher than those of synonymous ones in the lineage of A2 genes, implying the contribution of the positive selection on the encoded enzymes. Several sites of pepsin moieties were indeed found to be under positive selection, and most of them locate on the surface of the molecule, being involved in the conformational flexibility. Deduced from the known genomic structures of pepsinogen-A genes of primates and other mammals, the duplication/loss were frequent during their evolution. The extreme multiplication in the orangutan might be advantageous for digestion of herbaceous foods due to the increase in the level of enzymes in stomach and the diversification of enzyme specificit
Microwave imaging from total electric field data
A novel gradient-based inverse scattering method for imaging inhomogeneous objects from time-domain data of only total electric field is presented. Unlike most inverse scattering methods, the proposed method does not require the explicit information of the incident field illuminating a region of interest. Numerical simulations demonstrate the effectiveness of the method.2014 IEEE Antennas and Propagation Society International Symposium, APSURSI 2014; Memphis Convention CenterMemphis; United States; 6 July 2014 through 11 July 201
Application of time reversal to imaging electrical properties of inhomogeneous cylindrical objects
A time-domain inverse scattering approach using time-reversed fields for reconstructing electrical parameters of cylindrical objects has been proposed in a previous work. The approach does not require the explicit knowledge of incident fields illuminating the object. The cost functional represented in terms of the time-reversed fields was minimized by a genetic algorithm (GA). In this paper, we propose a gradient-based minimization for reconstruction of an inhomogeneous object for which GA can not be applied due to computational complexity. The time-reversed fields are calculated by time-reversing the equivalent current sources determined by the total fields recorded on a measurement line. Numerical simulations are carried out to show the effectiveness of the proposed method.8th European Conference on Antennas and Propagation, EuCAP 2014; The Hague; Netherlands; 6 April 2014 through 11 April 201
Development of a method to rapidly assess resistance/susceptibility of Micro-Tom tomatoes to Tomato yellow leaf curl virus via agroinoculation of cotyledons
Objective: Tomato yellow leaf curl virus (TYLCV) is one of the pathogens severely damaging tomato crops. Therefore, methods to treat or prevent TYLCV infection need to be developed. For this purpose, a method to conveniently and quickly assess infection of tomatoes by TYLCV is desired. In the present study, we established a quick method to evaluate TYLCV infection using cotyledons of Micro-Tom, a miniature tomato cultivar.
Results: First, we constructed a binary plasmid harboring 1.5 copies of the TYLCV genome and transformed Agrobacterium with the plasmid. By injecting agroinoculum from the resulting transformant into the branches of Micro-Tom, we confirmed the susceptibility of Micro-Tom to TYLCV. To shorten the evaluation process of TYLCV infection further, we agroinoculated cotyledons of Micro-Tom 10 days after sowing seeds. We consistently observed typical symptoms of TYLCV infection on true leaves 10 days after agroinoculation. Molecular analysis detected TYLCV progeny DNA in all leaves demonstrating symptoms 6 days after agroinoculation. Therefore, our new protocol enabled assessment of TYLCV infection within 20 days after sowing seeds. Thus, agroinoculation of Micro-Tom cotyledons will accelerate the process of screening TYLCV-resistant Micro-Toms and enable screening of larger numbers of plants more quickly, contributing to the development of TYLCV-resistant tomatoes
Image reconstruction of objects with time reversal and equivalent fields
Most inversion schemes for reconstructing electrical parameter distributions of unknown objects assume the explicit knowledge of incident fields illuminating them. We have proposed an inversion approach based on the field equivalence principle without requiring the knowledge of incident fields. The approach, however, requires measurement of both electric and magnetic tangential components of total field on the observation surface. In this paper, a new inversion scheme for the reconstruction from measured data of only electric tangential components is presented using time reversal and equivalent fields. Numerical reconstruction examples show the validity of the proposed scheme.2013 15th International Conference on Electromagnetics in Advanced Applications, ICEAA 2013; Turin; Italy; 9 September 2013 through 13 September 201
Acoustic stiffness and change in plug cartilage over time after autologous osteochondral grafting: correlation between ultrasound signal intensity and histological score in a rabbit model
We investigated quantitative changes over time in ultrasound signal intensity (an index of stiffness), signal duration (an index of surface irregularity), and interval between signals (an index of thickness) of plug cartilage in an animal model of autologous osteochondral grafting. A full-thickness osteochondral plug was surgically removed and replaced in male Japanese white rabbits (n = 22). Specimens obtained at day 0 and weeks 2, 4, 8, 12 and 24 postoperatively were assessed using an ultrasound system and by macroscopic and histological evaluation (modified Mankin's score). Histology revealed that the plug sank until 2 weeks postoperatively, and that newly formed cartilage-like tissue covered the plug, but at 24 weeks the tissue detached. The plug itself survived well throughout the period of observation. Although the signal intensity at the plug site was same as that in the sham operated contralateral knee at day 0, from 2 to 24 weeks postoperatively it was less than that in the sham knee. At 8 weeks, this difference was significant (P < 0.05). Modified Mankin's score revealed early degenerative changes at the site, but macroscopic examination did not. Signal intensity correlated significantly with score (both at day 0 and at the five postoperative time points [P < 0.05, r = -0.91] and as a whole [P < 0.05, r = -0.36]). Signal intensity also significantly correlated with the individual subscores for 'cartilage structure' (P < 0.05, r = -0.32) and 'cartilage cells' (P < 0.05, r = -0.30) from the modified Mankin's score, but not significantly with subscores for 'staining' and 'tidemark'. Signal duration correlated significantly with total score (as a whole [P < 0.05, r = 0.34]), but not significantly with the score for cartilage structure (P = 0.0557, r = 0.29). The interval between signals reflected well the actual thickness of the plug site. The significant relationships between ultrasound signal intensity and scores suggest that early degenerative changes in plug cartilage and cartilage-like tissue, especially in the superficial layer, are detectable by high-frequency ultrasound assessment
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