| 1. |
- Zhang, Feifei, et al.
(författare)
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Diversity of the Gut Microbiota in Dihydrotestosterone-Induced PCOS Rats and the Pharmacologic Effects of Diane-35, Probiotics, and Berberine. : Gut Microbiota in Dihydrotestosterone-Induced PCOS Rats
- 2019
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Ingår i: Frontiers in microbiology. - : Frontiers Media SA. - 1664-302X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Polycystic ovary syndrome (PCOS) is a frequent endocrine and metabolic syndrome in reproductive-age women. Recently, emerging evidence has shown that gut microbiota is closely related to metabolic diseases such as type 2 diabetes, obesity and PCOS. In the present study, we established dihydrotestosterone (DHT)-induced PCOS rats and used Illumina MiSeq sequencing (PE300) to examine the composition, diversity, and abundance of the gut microbiota in PCOS. We compared the effects of three PCOS treatments: Diane-35 (estrogen and progesterone), probiotics and berberine. The DHT-induced rats showed constant estrous cycles, the loss of mature ovarian follicles, insulin resistance and obesity. The reproductive and metabolic functions in the PCOS rats were improved by treatment with Diane-35 and probiotics. Diane-35 and probiotics could restore the diversity of the gut microbiota, and the recovery of gut microbiota disorders improved the reproductive function in PCOS-like rats. However, berberine drastically reduced the species diversity and amount of gut microbiota and showed no improvement in PCOS. The findings of this study will help us to better understand the influence of the gut microbiota in the metabolic and reproductive alterations in PCOS as well as suggest opportunities for future personal dietary guidance for PCOS.
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| 2. |
- Cheng, Qing, et al.
(författare)
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A revisit to the role of Mo in an MP35N superalloy : An experimental and theoretical study
- 2023
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Ingår i: Journal of Materials Science & Technology. - : Elsevier BV. - 1005-0302. ; 157, s. 60-70
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Tidskriftsartikel (refereegranskat)abstract
- Molybdenum (Mo) has been recognized as an essential alloying element of the MP35N (Co35.4Cr22.9Ni35.5Mo6.2, at.%) superalloy for enhancing strength and corrosion resistance. However, a full understanding of the addition of Mo on microstructure and mechanical properties of the Mo-free parent alloy is lacking. In this work, we consider five (Co37.7Cr24.4Ni37.9)100-xMox (x = 0, 0.7, 2.0, 3.2, and 6.2) alloys, and reveal that yield/tensile strength and ductility are continuously increased for these alloys with increasing Mo content while a single-phase face-centered cubic structure remains unchanged. It is found that strong solid solution strengthening (SSS) is a main domain to the improved yield strength, whereas grain boundaries are found to soften by the Mo addition. The first-principles calculations demonstrate that a severe local lattice distortion contributes to the enhanced SSS, and the grain boundary softening effect is mostly associated with the decreased shear modulus. Both first-principles calculations and scanning transmission electron microscopy observations reveal that the stacking fault energy (SFE) reduces by the Mo addition. The calculated SFE value decreases from 0.4 mJ/m2 to-11.8 mJ/m2 at 0 K as Mo content increases from 0 at.% to 6.2 at.%, and experimentally measured values of SFE at room temperature for both samples are about 18 mJ/m2 and 9 mJ/m2, respectively. The reduction of SFE promoted the generation of stacking faults and deformation twins, which sustain a high strain hardening rate, thus postponing necking instability and enhancing tensile strength and elongation.
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| 3. |
- Cheng, Q., et al.
(författare)
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Solid solution softening in a Aloi CoCrFeMnNi high-entropy alloy
- 2020
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Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 186, s. 63-68
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Tidskriftsartikel (refereegranskat)abstract
- Solute effects on high-entropy alloys of equiatomic proportions are scientifically intriguing because there is no such well-defined "solute" and "solvent" atoms compared to those of conventional single principal element alloys. To date, most of the face-centered cubic alloys exhibit solid solution strengthening rather than softening due to the interactions between dislocations and solute atoms. Here, we present the careful experimental measurements and demonstrate solid solution softening, albeit weak, in a single phase CoCrFeMnNi through the minor addition of 2. at.% Al. This softening effect is mostly related to the decreased Peierl's stress by Al addition.
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| 4. |
- Cheng, Q., et al.
(författare)
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Unveiling anneal hardening in dilute Al-doped AlxCoCrFeMnNi (x=0, 0.1) high-entropy alloys
- 2021
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Ingår i: Journal of Materials Science & Technology. - : Elsevier BV. - 1005-0302. ; 91, s. 270-277
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Tidskriftsartikel (refereegranskat)abstract
- Anneal hardening has been one of the approaches to improve mechanical properties of solid solution alloys with the face-centered cubic (FCC) structure, whereby a considerable strengthening can be attained by annealing of cold-worked alloys below the recrystallization temperature (T-rx). Microscopically, this hardening effect has been ascribed to several mechanisms, i.e. solute segregation to defects (dislocation and stacking fault) and short-range chemical ordering, etc. However, none of these mechanisms can well explain the anneal hardening recently observed in phase-pure and coarse-grained FCC-structured high-entropy alloys (HEAs). Here we report the observations, using high-resolution electron channeling contrast imaging and transmission electron microscopy, of profuse and stable dislocation substructures in a cold-rolled CoCrFeMnNi HEA subject to an annealing below T-rx. The dislocation substructures are observed to be thermally stable up to T-rx, which could arise from the chemical complexity of the high-entropy system where certain elemental diffusion retardation occurs. The microstructure feature is markedly different from that of conventional dilute solid solution alloys, in which dislocation substructures gradually vanish by recovery during annealing, leading to a strength drop. Furthermore, dilute addition of 2 at.% Al leads to a reduction in both microhardness and yield strength of the cold-rolled and subsequently annealed (<= 500 degrees C) HEA. This Al induced softening effect, could be associated with the anisotropic formation of dislocation substructure, resulting from enhanced dislocation planar slip due to glide plane softening effect. These findings suggest that the strength of HEAs can be tailored through the anneal hardening effect from dislocation substructure strengthening.
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| 5. |
- Cui, Peng, et al.
(författare)
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Long-term androgen excess induces insulin resistance and non-alcoholic fatty liver disease in PCOS-like rats.
- 2021
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Ingår i: The Journal of steroid biochemistry and molecular biology. - : Elsevier BV. - 1879-1220 .- 0960-0760. ; 208
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Tidskriftsartikel (refereegranskat)abstract
- Women with polycystic ovary syndrome (PCOS) are at higher risk for metabolic disorders compared to healthy women, and about 51 % of women with PCOS suffer from non-alcoholic fatty liver disease (NAFLD). Investigation into the pathological mechanism behind this association will provide insights for the prevention and treatment of this complication.Dihydrotestosterone (DHT), a nonaromatic androgen, was used to mimic the pathological conditions of hyperandrogenism and insulin resistance. Hematoxylin and eosin staining, Oil Red O staining, immunofluorescent staining, Western blots, and qRT-PCR were used to verify the hepatic steatosis and inflammation, and the latter two methods were also used for energy and mitochondrion-related assays. ELISA was used to measure the level of reactive oxygen species.Twelve weeks of DHT exposure led to obesity and insulin resistance as well as hepatic steatosis, lipid deposition, and different degrees of inflammation. The expression of molecules involved in respiratory chain and aerobic respiration processes, such as electron transfer complex II, pyruvate dehydrogenase, and succinate dehydrogenase complex subunit A, was inhibited. In addition, molecules associated with apoptosis and autophagy were also abnormally expressed, such as increased Bak mRNA, an increased activated caspase-3 to caspase-3 ratio, and increased Atg12 protein expression. All of these changes are associated with the mitochondria and lead to lipid deposition and inflammation in the liver.Long-term androgen excess contributes to insulin resistance and hepatic steatosis by affecting mitochondrial function and causing an imbalance in apoptosis and autophagy, thus suggesting the pathogenesis of NAFLD in women with PCOS.
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| 6. |
- Huang, He, et al.
(författare)
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Material informatics for uranium-bearing equiatomic disordered solid solution alloys
- 2021
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Ingår i: Materials Today Communications. - : Elsevier BV. - 2352-4928. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- Near-equiatomic, multi-component alloys with disordered solid solution phase (DSSP) are associated with outstanding performance in phase stability, mechanical properties and irradiation resistance, and may provide a feasible solution for developing novel uranium-based alloys with better fuel capacity. In this work, we build a machine learning (ML) model of disordered solid solution alloys (DSSAs) based on about 6000 known multicomponent alloys and several materials descriptors to efficiently predict the DSSAs formation ability. To fully optimize the ML model, we develop a multi-algorithm cross-verification approach in combination with the SHapley Additive exPlanations value (SHAP value). We find that the Delta S-C, Lambda, Phi(s), gamma and 1/Omega, corresponding to the former two Hume - Rothery (H - R) rules, are the most important materials descriptors affecting DSSAs formation ability. When the ML model is applied to the 375 uranium-bearing DSSAs, 190 of them are predicted to be the DSSAs never known before. 20 of these alloys were randomly synthesized and characterized. Our predictions are in-line with experiments with 3 inconsistent cases, suggesting that our strategy offers a fast and accurate way to predict novel multi-component alloys with high DSSAs formation ability. These findings shed considerable light on the mapping between the material descriptors and DSSAs formation ability.
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| 7. |
- Meng, Xiangqi, et al.
(författare)
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A Novel Intelligent Nonlinear Controller for Dual Active Bridge Converter With Constant Power Loads
- 2023
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Ingår i: IEEE Transactions on Industrial Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0278-0046 .- 1557-9948. ; 70:3, s. 2887-2896
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Tidskriftsartikel (refereegranskat)abstract
- The stability of dual active bridge converter (DAB) is threatened when feeding the constant power loads (CPLs). This article proposes a deep reinforcement learning-based backstepping control strategy to solve this problem. First, a nonlinear disturbance observer is adopted to estimate the large-signal nonlinear disturbance. Then, a backstepping controller is used to stabilize the voltage response of the DAB under the large-signal disturbance. Finally, a compensation method based on deep reinforcement learning is developed to intelligently minimize output voltage tracking error and improve the operating efficiency of the system. The proposed controller can guarantee system stability under the large-signal disturbance of the CPL and achieve a fast dynamic response with accurate voltage tracking; it is more adaptive by using the deep reinforcement learning technique through the learning of its neural networks. The effectiveness of the proposed controller is verified by experiments.
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| 8. |
- Xu, W. W., et al.
(författare)
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Atomic origins of the plastic deformation micro-mechanisms of ?/?? : FeCoNiAlTi high-entropy alloys
- 2022
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Ingår i: International journal of plasticity. - : Elsevier BV. - 0749-6419 .- 1879-2154. ; 158, s. 103439-
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Tidskriftsartikel (refereegranskat)abstract
- The gamma/gamma' FeCoNiAlTi high-entropy alloys (HEAs) break the strength-ductility trade-off and possess an excellent combination of strength and ductility. However, lack of atomic-level understanding of plastic deformation behaviors restricts the exploration of full capacities of the FeCoNiAlTi HEAs. By computing the generalized stacking fault energies (GSFEs) of the gamma and gamma' phases, the relationships between planar stacking faults and work-hardening capacities, and the effect of chemical concentration and grain orientation on the deformation mechanisms were explored in depth for the FeCoNiAlTi HEAs. Our results demonstrate that the multicomponent nature lowers the GSFEs of the matrix but enhances those of the precipitate to achieve the strength-ductility balance of the HEA. An active factor (epsilon) defined as gamma isf/gamma apb (gamma isf: intrinsic stacking fault energy, gamma apb: anti-phase boundary energy) was introduced to bridge activation of microbands (MBs) and planar stacking faults in the gamma/gamma' alloys. Tuning a suitable low epsilon around 0.2 is an efficient strategy for acquiring the extended MBs-induced plasticity. Analyzing the individual/synergetic contribution of the principal elements to the GSFEs-related properties, we find that increasing the amount of Co and Ti promotes the strength-ductility balance and facilitates the MB activation by altering the GSFEs of both gamma and gamma'. Based on our comprehensive analysis, it is concluded that raising the Co/Fe ratio or lowing the Al/Ti ratio benefits the achievement of the desired mechanical properties of the FeCoNiAlTi HEA.
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| 9. |
- Yu, Qiang, et al.
(författare)
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Unveiling segregation-induced evolution in phase constitution of Cu-containing high-entropy alloys
- 2020
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 843
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Tidskriftsartikel (refereegranskat)abstract
- A theoretical investigation of Cu segregation effect on phase constitution, magnetic, and mechanical properties of FeCoNi(CumAl)(x) high-entropy alloys is presented. Results show that the homogenous FeCoNi(Cu1.0Al)(x) only exists as a single face-centered cubic phase at arbitrary temperatures. The level of Cu-segregation determines the phase evolution amongst inhomogeneous single phase (0.75 <= m < 1.0), duplex phase (m << 0.75), and triple phase (m approximate to 0.75). Our results reproduce the observation. Only face-centered cubic phase can be formed for FeCoNi(CumAl)(x) with either rather low or extreme high content of (CumAl) even though the segregation occurred. The Cu addition lifts the total magnetic moments by enhancing the local magnetic moment of Fe, Co and Ni. The serious Cu segregation in the duplex-phase HEAs induces the decrease of ductility of fcc and bcc phases. The increasing Cu enhances the strength of Cu-rich fcc phase and the decreasing Cu weakens that of Cu-poor bcc phase.
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