167 research outputs found

    Neutron diffraction study of mechanically alloyed and <i>in situ</i> annealed Al<sub>75</sub>Mo<sub>25</sub> powders

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    The mechanical treatment of a Al75Mo25 mixture of pure elemental powders in a high-energy mixer mill induces partial solid state reactivity and solid solution formation. This is suggested by a quantitative phase evaluation and by the changes of Al lattice parameter carried out with Rietveld analysis of diffraction patterns collected after extended time of processing (4, 8, 16, 32, 57, and 78 h). The small angle neutron scattering experiments showed that diffusion processes are the rate-controlling step for these solid state reactions. The formation of metastable phases is confirmed by in situ neutron diffraction annealing experiments on selected as-milled powders. In the specimen mechanically alloyed for 4 h, Al12Mo phase is formed at 590 °C (below the aluminum melting point). Soon after this temperature, the remaining Al is consumed to form the Al8Mo3 phase. In the alloy mechanically treated for 32 h, the Al12Mo phase appears after annealing at 430 °C, while the Al8Mo3 phase is found at 493 °C. After the disappearance of Al12Mo phase (500 °C), the solid state reaction proceeds to form a new tetragonal Al3Mo phase, not reported in the equilibrium phase diagram. In the specimen mechanically treated for 57 h, the total formation of Al8Mo3 is recorded at 430 °C. Conversely, in the powder ball milled for 78 h, the Al8Mo3 phase appears at 390 °C and coexists with tetragonal Al3Mo

    Histological Feature of Ovarian Structures Throughout the Reproductive Cycle in Alpine Goats (Capra Hircus)

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    AbstractThe knowledge about ovarian physiology in small ruminants is still limited, especially when compared to other domestic species. Ovarian function in goats is mainly assessed by ultrasonographic techniques, whereas a quali-quantitative feature of the follicular and luteal structures throughout the reproductive cycle in naturally cycling goats is scarce. This study provides a detailed description of the functional morphology and size of 742 ovarian structures (follicles, corpora hemorrhagica and corpora lutea) in relation to the oestrus phase, the body weight and the age of 25 Alpine goats (Capra hircus). The current study demonstrated that, the number and size of the follicles were related to the stage of the reproductive cycle (P 4 mm) (P < 0.001), and small follicles (< 2 mm; P < 0.05) varied throughout the reproductive cycle, while medium follicles (2-3 mm) were invariably observed. Large and very large follicles were predominant during the diestrus phase and small follicles in the prepubertal anestrus. It is evident from the current study that the number of follicles (P < 0.05) was significantly affected with both body weight and age. On the other hand, the size of follicles was significantly affected with body weight only (P < 0.0001). These results could contribute to a deeper understanding of ovarian transformations with important implications in assisted reproductive technologies, thereby concurring in advancing the efficiency of ultrasound in breeding programs for this species

    Structural and elastic behavior of Fe<sub>50</sub>Al<sub>50</sub> nanocrystalline alloys

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    Pure iron and aluminum powders were mixed in the equiatomic ratio and mechanically alloyed in a high-energy ball mill for different times. Structure refinement of x-ray powder diffraction data was performed to study the structural transformations induced by mechanical and subsequent thermal annealing treatments. The mechanical alloying (MA) process induces a progressive dissolution of aluminum phase into the bcc iron phase. After 32 h of MA a single-phase Fe(Al) bcc extended solid solution, with lattice parameter a0 = 2.891 Å, average coherent domain size &lt;D&gt; ≈50 Å, and lattice strain 0.5%, was observed. The annealing of the specimens after MA up to 8 h favored the aluminum dissolution in a-iron and the precipitation of the Al5Fe2 phase, whereas a nanostructured B2 FeAl intermetallic compound was observed in the annealed samples which were previously milled for 8, 16, and 32 h. In the same specimens a minority cubic phase Fe3AlCX, anti-isomorphous with perovskite, derived from contamination of ethanol and introduced in the steel vial as a lubricant agent, was also observed. Anelasticity measurements have shown the occurrence of two main transient effects during the first thermal run. The first one occurring at 500 K in all mechanically alloyed specimens was attributed to thermally activated structural transformations, whereas the second at about 700 K was attributed to a magnetic order–disorder transition. During the second run of anelasticity measurements a relaxation peak P1 in the nanostructured B2 FeAl intermetallic compound, attributed to grain-boundary sliding mechanisms and with an activation energy of 1.8 ± 0.2 eV was observed. In specimens milled for 8–32 h a second small peak P2 at the low-temperature tail of the P1 peak was observed and tentatively attributed to a Zener-type relaxation

    Genomic analysis suggests KITLG is responsible for a roan pattern in two Pakistani goat breeds

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    The roan coat color pattern is described as the presence of white hairs intermixed with pigmented hairs. This kind of pigmentation pattern has been observed in many domestic species, including the goat. The molecular mechanisms and inheritance that underlie this pattern are known for some species and the KITLG gene has been shown associated with this phenotype. To date, no research effort has been done to find the gene(s) that controls roan coat color pattern in goats. In the present study, after genotyping with the GoatSNP50 BeadChip, 35 goats that showed a roan pattern and that belonged to two Pakistan breeds (Group A) were analyzed and then compared to 740 goats of 39 Italian and Pakistan goats breeds that did not have the same coat color pattern (Group B). Run of homozygosity-based and XP-EHH analyses were used to identify unique genomic regions potentially associated with the roan pattern. A total of 3 regions on chromosomes 5, 6 and 12 were considered unique among the group A versus B group comparisons. The A region > 1.7 Mb on chromosome 5 was the most divergent between the two groups. This region contains six genes, including the KITLG gene. Our findings support the hypothesis that the KITLG gene may be associated with the roan phenotype in goats

    Runs of homozygosity in the Italian goat breeds: impact of management practices in low‑input systems

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    Background Climate and farming systems, several of which are considered as low-input agricultural systems, vary between goat populations from Northern and Southern Italy and have led to different management practices. These processes have impacted genome shaping in terms of inbreeding and regions under selection and resulted in differences between the northern and southern populations. Both inbreeding and signatures of selection can be pinpointed by the analysis of runs of homozygosity (ROH), which provides useful information to assist the management of this species in different rural areas. Results We analyzed the ROH distribution and inbreeding (FROH) in 902 goats from the Italian Goat Consortium2 dataset. We evaluated the differences in individual ROH number and length between goat breeds from Northern (NRD) and Central-southern (CSD) Italy. Then, we identified the signatures of selection that differentiate these two groups using three methods: ROH, ΔROH, and averaged FST. ROH analyses showed that some Italian goat breeds have a lower inbreeding coefficient, which is attributable to their management and history. ROH are longer in breeds that are undergoing non-optimal management or with small population size. In several small breeds, the ROH length classes are balanced, reflecting more accurate mating planning. The differences in climate and management between the NRD and CSD groups have resulted in different ROH lengths and numbers: the NRD populations bred in isolated valleys present more and shorter ROH segments, while the CSD populations have fewer and longer ROH, which is likely due to the fact that they have undergone more admixture events during the horizontal transhumance practice followed by a more recent standardization. We identified four genes within signatures of selection on chromosome 11 related to fertility in the NRD group, and 23 genes on chromosomes 5 and 6 related to growth in the CSD group. Finally, we identified 17 genes on chromosome 12 related to environmental adaptation and body size with high homozygosity in both groups. Conclusions These results show how different management practices have impacted the level of genomic inbreeding in two Italian goat groups and could be useful to assist management in a low-input system while safeguarding the diversity of small populations

    Prognostic and predictive role of EGFR pathway alterations in biliary cancer patients treated with chemotherapy and anti-EGFR

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    The association of anti-EGFR to gemcitabine and oxaliplatin (GEMOX) chemotherapy did not improve survival in biliary tract carcinoma (BTC) patients. Multiple mechanisms might be involved in the resistance to anti-EGFR. Here, we explored the mutation profile of EGFR extracellular domain (ECD), of tyrosine kinase domain (TKD), and its amplification status. EGFR mutational status of exons 12, 18-21 was analyzed in 57 tumors by Sanger sequencing. EGFR amplification was evaluated in 37 tumors by Fluorescent In Situ Hybridization (FISH). Kaplan-Meier curves were calculated using the log-rank test. Six patients had mutations in exon 12 of EGFR ECD and 7 in EGFR TKD. Neither EGFR ECD nor TKD mutations affected progression free survival (PFS) or overall survival (OS) in the entire population. In the panitumumab plus GEMOX (P-GEMOX) arm, ECD mutated patients had a worse OS, while EGFR TKD mutated patients had a trend towards shorter PFS and OS. Overall, the presence of mutations in EGFR or in its transducers did not affect PFS or OS, while the extrahepatic cholangiocarcinoma (ECC) mutated patients had a worse prognosis compared to WT. Nineteen out of 37 tumors were EGFR amplified, but the amplification did not correlate with survival. ECC EGFR amplified patients had improved OS, whereas the amplification significantly correlated with poor PFS (p = 0.03) in gallbladder carcinoma patients. The high molecular heterogeneity is a predominant feature of BTC: the alterations found in this work seem to have a prognostic impact rather than a predictive role towards anti-EGFR therapy

    Donor Cell Acute Myeloid Leukemia after Hematopoietic Stem Cell Transplantation for Chronic Granulomatous Disease: A Case Report and Literature Review

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    The patient reported here underwent hematopoietic stem cell transplantation (HSCT) due to chronic granulomatous disease (CGD) caused by biallelic mutations of the NCF1 gene. Two years later, he developed AML, which was unexpected and was recognized via sex-mismatched chromosomes as deriving from the donor cells; the patient was male, and the donor was his sister. Donor cell leukemia (DCL) is very rare, and it had never been reported in patients with CGD after HSCT. In the subsequent ten years, the AML relapsed three times and the patient underwent chemotherapy and three further HSCTs; donors were the same sister from the first HSCT, an unrelated donor, and his mother. The patient died during the third relapse. The DCL was characterized since onset by an acquired translocation between chromosomes 9 and 11, with a molecular rearrangement between the MLL and MLLT3 genes-a quite frequent cause of AML. In all of the relapses, the malignant clone had XX sex chromosomes and this rearrangement, thus indicating that it was always the original clone derived from the transplanted sister's cells. It exhibited the ability to remain quiescent in the BM during repeated chemotherapy courses, remission periods and HSCT. The leukemic clone then acquired different additional anomalies during the ten years of follow-up, with cytogenetic results characterized both by anomalies frequent in AML and by different, non-recurrent changes. This type of cytogenetic course is uncommon in AML

    Genetic diversity of Italian goat breeds assessed with a medium-density SNP chip

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    Background: Among the European countries, Italy counts the largest number of local goat breeds. Thanks to the recent availability of a medium-density SNP (single nucleotide polymorphism) chip for goat, the genetic diversity of Italian goat populations was characterized by genotyping samples from 14 Italian goat breeds that originate from different geographical areas with more than 50 000 SNPs evenly distributed on the genome. Results: Analysis of the genotyping data revealed high levels of genetic polymorphism and an underlying North-south geographic pattern of genetic diversity that was highlighted by both the first dimension of the multi-dimensional scaling plot and the Neighbour network reconstruction. We observed a moderate and weak population structure in Northern and Central-Southern breeds, respectively, with pairwise FST values between breeds ranging from 0.013 to 0.164 and 7.49 % of the total variance assigned to the between-breed level. Only 2.11 % of the variance explained the clustering of breeds into geographical groups (Northern, Central and Southern Italy and Islands). Conclusions: Our results indicate that the present-day genetic diversity of Italian goat populations was shaped by the combined effects of drift, presence or lack of gene flow and, to some extent, by the consequences of traditional management systems and recent demographic history. Our findings may constitute the starting point for the development of marker-assisted approaches, to better address future breeding and management policies in a species that is particularly relevant for the medium-and long-term sustainability of marginal regions
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