51 research outputs found
Genomic prediction for growth using a low-density SNP panel in dromedary camels
For thousands of years, camels have produced meat, milk, and fiber in harsh desert conditions. For a sustainable development to provide protein resources from desert areas, it is necessary to pay attention to genetic improvement in camel breeding. By using genotyping-by-sequencing (GBS) method we produced over 14,500 genome wide markers to conduct a genome- wide association study (GWAS) for investigating the birth weight, daily gain, and body weight of 96 dromedaries in the Iranian central desert. A total of 99 SNPs were associated with birth weight, daily gain, and body weight (p-value \u3c 0.002). Genomic breeding values (GEBVs) were estimated with the BGLR package using (i) all 14,522 SNPs and (ii) the 99 SNPs by GWAS. Twenty-eight SNPs were associated with birth weight, daily gain, and body weight (p-value \u3c 0.001). Annotation of the genomic region (s) within ± 100 kb of the associated SNPs facilitated prediction of 36 candidate genes. The accuracy of GEBVs was more than 0.65 based on all 14,522 SNPs, but the regression coefficients for birth weight, daily gain, and body weight were 0.39, 0.20, and 0.23, respectively. Because of low sample size, the GEBVs were predicted using the associated SNPs from GWAS. The accuracy of GEBVs based on the 99 associated SNPs was 0.62, 0.82, and 0.57 for birth weight, daily gain, and body weight. This report is the first GWAS using GBS on dromedary camels and identifies markers associated with growth traits that could help to plan breeding program to genetic improvement. Further researches using larger sample size and collaboration of the camel farmers and more profound understanding will permit verification of the associated SNPs identified in this project. The preliminary results of study show that genomic selection could be the appropriate way to genetic improvement of body weight in dromedary camels, which is challenging due to a long generation interval, seasonal reproduction, and lack of records and pedigrees
Genomic prediction for growth using a low-density SNP panel in dromedary camels
For thousands of years, camels have produced meat, milk, and fiber in harsh desert conditions. For a sustainable development to provide protein resources from desert areas, it is necessary to pay attention to genetic improvement in camel breeding. By using genotyping-by-sequencing (GBS) method we produced over 14,500 genome wide markers to conduct a genome- wide association study (GWAS) for investigating the birth weight, daily gain, and body weight of 96 dromedaries in the Iranian central desert. A total of 99 SNPs were associated with birth weight, daily gain, and body weight (p-value \u3c 0.002). Genomic breeding values (GEBVs) were estimated with the BGLR package using (i) all 14,522 SNPs and (ii) the 99 SNPs by GWAS. Twenty-eight SNPs were associated with birth weight, daily gain, and body weight (p-value \u3c 0.001). Annotation of the genomic region (s) within ± 100 kb of the associated SNPs facilitated prediction of 36 candidate genes. The accuracy of GEBVs was more than 0.65 based on all 14,522 SNPs, but the regression coefficients for birth weight, daily gain, and body weight were 0.39, 0.20, and 0.23, respectively. Because of low sample size, the GEBVs were predicted using the associated SNPs from GWAS. The accuracy of GEBVs based on the 99 associated SNPs was 0.62, 0.82, and 0.57 for birth weight, daily gain, and body weight. This report is the first GWAS using GBS on dromedary camels and identifies markers associated with growth traits that could help to plan breeding program to genetic improvement. Further researches using larger sample size and collaboration of the camel farmers and more profound understanding will permit verification of the associated SNPs identified in this project. The preliminary results of study show that genomic selection could be the appropriate way to genetic improvement of body weight in dromedary camels, which is challenging due to a long generation interval, seasonal reproduction, and lack of records and pedigrees
Gelcasting as a Novel Processing Route to Fabricate PartiallyStabilized Zirconia Ceramic Bodies: Gelcasting ceramic bodiesprocess
Bioinert ceramics, like alumina and zirconia are used mainly for replacementsof bones, hip joints and for dental implants. Partially stabilized zirconia ceramics(PSZ or TZPwith 3 mol.% or 5 wt.% Y2O3), appear as perspective bioinert ceramicsbecause of their high strength and corrosion resistance. In order to fabricate complexshapes, it is essential to use a near net shape processing like gelcasting as anuncomplicated method which has appropriate potential of producing special shapeswith suitable green and sintered properties (like high mechanical properties and almostfull density and machinability of green bodies). Moreover, biocompatibility studieshave proved that this processing route is nontoxic. In this experiment, micro-structural observation performed to illustrate the effect of dispersant on homogeneityof gelcast 3Y-TZPbodies. It has been shown that it is possible to achieve uniformmicrostructure by means of appropriate amount of dispersant and ultrasonic wave.In addition, the machinability of these green bodies has been proven and somecomplex shaped bodies fabricated, in order to illustrate the capability of the process
The effect of dolomite type and Al2O3 content on the phase composition in aluminous cements containing spinel
In this paper, the effect of dolomite type and Al2O3 content on the phase composition in aluminous cements containing MA spinel is investigated. For this reason, the raw and calcined dolomites are used as raw materials along with calcined alumina in the preparation of the cement. Then, different compositions are prepared at 1350°C using the sintering method and their mineralogical compositions are investigated using the diffractometric technique. Also, their microstructures arre evaluated. The results indicate that raw materials used have great effect on the type and amount of formed phases in cement composition. Independently of the dolomite type used, a mixed phase product consisting of spinel accompanied by CA and CA2 is obtained. The content of CA phase in the cement composition is decreased with increasing of Al2O3 in the raw materials composition. On the other hand, the content of CA2 phase is increased with the addition of Al2O3. In addition, the results show that the formation of C12A7 is favored by use of calcined dolomite
Spark plasma sintering of TaC-HfC UHTC via disilicides sintering aids
Ta0.8Hf0.2C ceramic has the highest melting point among the known materials (4000 degrees C). Spark plasma sintering is a new route for consolidation of materials, specially ultra high temperature ceramics (UHTCs), which are difficult to be sintered at temperatures lower than 2000 degrees C.
The purpose of this study is to consolidate Ta0.8Hf0.2C by spark plasma sintering at low temperature using MoSi2 and TaSi2 as sintering aid. In this regard, effect of different amounts of sintering aids and carbides ratio on densification behavior and mechanical properties of Ta1-xHfxC were investigated.
Fully consolidation of Ta0.8Hf0.2C was achieved in presence of 12 vol.% sintering aid after sintering at 1650 degrees C for 5 min under 30 MPa. The first stage of sintering was due to plastic deformation of sintering aids particles and consequent rearrangement. The second stage was occurred via Ta1-xHfxC solid solution and liquid phase formation
The Analysis of Torsional Shear Strength Test of Sealants for Solid Oxide Fuel Cells
A torsion test recently implemented for solid oxide fuel cell sealant materials is analyzed as a method for measuring the shear strength of sealant for solid oxide fuel cells. The finite element method is used to simulate the stress distribution in the hourglass-shaped steel specimens with intermediate sealant layer with different specimen's dimensions and configurations. Also, it is analyzed how stress concentration changes if the sealant does not completely fill the gap or is squeezed out of gap. The reduction of seal thickness to outer radius ratio results in an increase in stress concentration at the outer edge of sealant. The developed specimens with a hollow halve steel plate as well as the ones with two hollow halve steel plates appear to be suitable choices for torsional shear strength test, reducing the torque for fracture and stress concentrations. Effects of lack of filling and squeezing out of gap onto the stress distribution are negligible compared to the effect of pre-existing discontinuities
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