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Heat treatment is the critical step in achieving a refined microstructure and enhanced mechanical properties of TiAl-based alloys. This study investigated the influence of heat treatment temperature, cooling method, and heat treatment time on the microstructure and mechanical properties of an extruded powder metallurgy Ti-48Al alloy, and achieved the control of fully lamellar fine microstructures and the enhancement of performance through a simple heat treatment, rather than the traditional approach of homogenization followed by heat treatment. The results indicate that the heat treatment temperature determines the type of microstructure, while the cooling rate dictates the lamellar width. As the heat treatment temperature was increased from the two-phase region to the α single-phase region, the microstructure transitioned from duplex to near lamellar, and the alloy strength initially increased and then decreased, influenced by both the lamellar colony ratio and grain size. A rapid cooling rate (water quenching) induces a non-diffusive massive phase transformation, whereas a slow cooling rate (air cooling) gradually forms α2/γ lamellar colonies. Therefore, a suitable heat treatment regime for the powder metallurgy Ti-48Al alloy was determined to be 1340 °C/5 min/air cooling. The microstructure of the alloy was near lamellar, consisting of lamellar colonies approximately 50 μm and a small number of γ equiaxed grains of about 10 μm. Subsequently, the alloy exhibited a room temperature tensile strength of 784 MPa and a yield strength of 763 MPa, representing improvements of 17.0% and 38.7% over the extruded alloy, respectively. This research provides a reference for establishing a heat treatment process for powder metallurgy TiAl alloys. [ABSTRACT FROM AUTHOR]

Xinjiang brown cattle are highly resistant to disease and tolerant of roughage feeding. The identification of genes regulating mastitis resistance in Xinjiang brown cattle is a novel means of genetic improvement. In this study, the blood levels of IL-1β, IL-6, IL-10, TNF-α, and TGF-β in Xinjiang brown cattle with high and low somatic cell counts (SCCs) were investigated, showing that cytokine levels were higher in cattle with high SCCs. The peripheral blood transcriptomic profiles of healthy and mastitis-affected cattle were constructed by RNA-seq. Differential expression analysis identified 1632 differentially expressed mRNAs (DE-mRNAs), 1757 differentially expressed lncRNAs (DE-lncRNAs), and 23 differentially expressed circRNAs (DE-circRNAs), which were found to be enriched in key pathways such as PI3K/Akt, focal adhesion, and ECM-receptor interactions. Finally, ceRNA interaction networks were constructed using the differentially expressed genes and ceRNAs. It was found that keynote genes or mRNAs were also enriched in pathways such as PI3K-Akt, cholinergic synapses, cell adhesion molecules, ion binding, cytokine receptor activity, and peptide receptor activity, suggesting that the key genes and ncRNAs in the network may play an important role in the regulation of bovine mastitis. [ABSTRACT FROM AUTHOR]

Trichoderma reesei is a powerful fungal cell factory for the production of cellulolytic enzymes due to its outstanding protein secretion capacity. Endoplasmic reticulum-associated degradation (ERAD) plays an integral role in protein secretion that responds to secretion pressure and removes misfolded proteins. However, the role of ERAD in fungal growth and endogenous protein secretion, particularly cellulase secretion, remains poorly understood in T. reesei. Here, we investigated the ability of T. reesei to grow under different stresses and to secrete cellulases by disrupting three major genes (hrd1, hrd3 and der1) involved in the critical parts of the ERAD pathway. Under the ER stress induced by high concentrations of DTT, knockout of hrd1, hrd3 and der1 resulted in severely impaired growth, and the mutants Δhrd1 and Δhrd3 exhibited high sensitivity to the cell wall-disturbing agents, CFW and CR. In addition, the absence of either hrd3 or der1 led to the decreased heat tolerance of this fungus. These mutants showed significant differences in the secretion of cellulases compared to the parental strain QM9414. During fermentation, the secretion of endoglucanase in the mutants was essentially consistent with that of the parental strain, while cellobiohydrolase and β-glucosidase were declined. It was further discovered that the transcription levels of the endoglucanase-encoding genes (eg1 and eg2) and the cellobiohydrolase-encoding gene (cbh1) were not remarkedly changed. However, the β-glucosidase-encoding gene (bgl1) was significantly downregulated in the ERAD-deficient mutants, which was presumably due to the activation of a proposed feedback mechanism, repression under secretion stress (RESS). Taken together, our results indicate that a defective ERAD pathway negatively affects fungal growth and cellulase secretion, which provides a novel insight into the cellulase secretion mechanism in T. reesei. [ABSTRACT FROM AUTHOR]

Simple Summary: Body conformation traits are closely related to economically important characteristics and should be considered in cattle breeding programs. A variety of body conformation traits recorded by classifiers can complicate the analysis process. Factor analysis can reduce the number of variables by combining two or more variables into a single factor, which has biological significance. The results of this study could be used by breeders to define conformation indexes and implement genetic assessments for conformation traits in dual-purpose breeds. In this study, we estimated the genetic parameters for 6 composite traits and 27 body conformation traits of 1016 dual-purpose Simmental cattle reared in northwestern China from 2010 to 2019 using a linear animal mixed model. To integrate these traits, a variety of methods were used as follows: (1) genetic parameters estimates for composite and individual body conformation traits based on the pedigree relationship matrix (A) and combined genomic-pedigree relationship matrix (H); (2) factor analysis to explore the relationships among body conformation traits; and (3) genetic parameters of factor scores estimated using A and H, and the correlations of EBVs of the factor scores and EBVs of the composite traits. Heritability estimates of the composite traits using A and H were low to medium (0.07–0.47). The 24 common latent factors explained 96.13% of the total variance. Among factors with eigenvalues ≥ 1, F1 was mainly related to body frame, muscularity, and rump; F2 was related to feet and legs; F3, F4, F5, and F6 were related to teat placement, teat size, udder size, and udder conformation; and F7 was related to body frame. Single-trait analysis of factor scores yielded heritability estimates that were low to moderate (0.008–0.43 based on A and 0.04–0.43 based on H). Spearman and Pearson correlations, derived from the best linear unbiased prediction analysis of composite traits and factor scores, showed a similar pattern. Thus, incorporating factor analysis into the morphological evaluation to simplify the assessment of body conformation traits may improve the genetics of dual-purpose Simmental cattle. [ABSTRACT FROM AUTHOR]

Preparing high relative density γ-TiAl alloy by pressure-less sintering at low-cost has always been a challenge. Therefore, a new kind of non-spherical pre-alloyed TiAl powder was prepared by the reaction of TiH2 powder and Al powder at 800 °C to fabricate high-density Ti-48Al alloy via pressure-less sintering. The oxygen content was controlled to below 1800 ppm by using coarse Al powder (~120 μm). The sintered densities ranged from 92.1% to 97.5% with sintering temperature varying from 1300 °C to 1450 °C. The microstructure of the sintered compact was greatly influenced by the sintering temperature. The as-sintered samples had a near-γ structure at 1350 °C, a duplex structure at 1400 °C, and a nearly lamellar structure at 1450 °C. To achieve full densification, non-capsule hot isostatic pressing was performed on the 1350 °C and 1400 °C sintered samples. As a result, high compressive strengths of 2241 MPa and 1931MPa were obtained, which were higher than the existing Ti-48Al alloys. [ABSTRACT FROM AUTHOR]