Shanghai University

About: Shanghai University is a education organization based out in Shanghai, Shanghai, China. It is known for research contribution in the topics: Microstructure & Graphene. The organization has 59583 authors who have published 56840 publications receiving 753549 citations. The organization is also known as: Shànghǎi Dàxué.

Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys

Abstract: In human-made malleable materials, microdamage such as cracking usually limits material lifetime. Some biological composites, such as bone, have hierarchical microstructures that tolerate cracks but cannot withstand high elongation. We demonstrate a directionally solidified eutectic high-entropy alloy (EHEA) that successfully reconciles crack tolerance and high elongation. The solidified alloy has a hierarchically organized herringbone structure that enables bionic-inspired hierarchical crack buffering. This effect guides stable, persistent crystallographic nucleation and growth of multiple microcracks in abundant poor-deformability microstructures. Hierarchical buffering by adjacent dynamic strain-hardened features helps the cracks to avoid catastrophic growth and percolation. Our self-buffering herringbone material yields an ultrahigh uniform tensile elongation (~50%), three times that of conventional nonbuffering EHEAs, without sacrificing strength.

Epimedium‐Derived Phytoestrogen Flavonoids Exert Beneficial Effect on Preventing Bone Loss in Late Postmenopausal Women: A 24‐Month Randomized, Double‐Blind and Placebo‐Controlled Trial

Abstract: Epimedium brevicornum maxim, a nonleguminous medicinal plant, has been found to be rich in phytoestrogen flavonoids. Results from a 24-month randomized double-blind placebo-controlled clinical trial showed that Epimedium-derived phytoestrogen flavonoids were able to exert beneficial effects on preventing bone loss in late postmenopausal women, without resulting in a detectable hyperplasia effect on the endometrium. Introduction: We performed a 24-mo randomized double-blind placebo-controlled clinical trial for evaluating the effect of the Epimedium-derived phytoestrogen flavonoids (EPFs) on BMD, bone turnover biochemical markers, serum estradiol, and endometrial thickness in postmenopausal women. Materials and Methods: One hundred healthy late postmenopausal women, with a natural menopausal history within 10 ∼18 yr and with a BMD T-score at the lumbar spine between −2 and −2.5 SD, were randomized into EPF treatment group (n = 50; a daily dose of 60 mg Icariin, 15 mg Daidzein, and 3 mg Genistein) or placebo control group (n = 50). All participants received 300 mg element calcium daily. BMD, bone turnover biochemical markers, serum estradiol, and endometrial thickness were measured at baseline and 12 and 24 mo after intervention. Results: Eighty-five participants completed the trial. The patterns of BMD changes were significantly different between the EPF treatment group and placebo control group by repeated-measures ANOVA (p = 0.045 for interaction between time and group at femoral neck; p = 0.006 for interaction between time and group at lumbar spine). BMD was found with a decreased tendency in the placebo control group at 12 (femoral neck: −1.4%, p = 0.104; lumbar spine: −1.7%, p = 0.019) and 24 mo (femoral neck: −1.8%, p = 0.048; lumbar spine: −2.4%, p = 0.002), whereas EPF treatment maintained BMD at 12 (femoral neck: 1.1%, p = 0.285; lumbar spine:1.0%, p = 0.158) and 24 mo (femoral neck: 1.6%, p = 0.148; lumbar spine: 1.3%, p = 0.091). The difference in lumbar spine between the two groups was significant at both 12 (p = 0.044) and 24 mo (p = 0.006), whereas the difference in the femoral neck was marginal at 12 mo (p = 0.061) and significant at 24 mo (p = 0.008). Levels of bone biochemical markers did not change in the placebo control group. In contrast, EPF intervention significantly decreased levels of deoxypyrdinoline at 12 (−43%, p = 0.000) and 24 mo (−39%, p = 0.000), except for osteocalcin at 12 (5.6%, p = 0.530) and 24 mo (10.7%, p = 0.267). A significant difference in deoxypyrdinoline between the two groups was found at both 12 (p = 0.000) and 24 mo (p = 0.001). Furthermore, neither serum estradiol nor endometrial thickness was found to be changed in either groups during the clinical trial. Conclusions: EPFs exert a beneficial effect on preventing bone loss in late postmenopausal women without resulting in a detectable hyperplasia effect on the endometrium.

Robust, Fire-Safe, Monomer-Recovery, Highly Malleable Thermosets from Renewable Bioresources

Abstract: Conventional thermosets are built by nonrenewable fossil resources and are arduous to be reprocessed, recycled, and reshaped due to their permanent covalent cross-linking, and their flammability makes them unsafe during use. Here, for the first time, we synthesized a novel Schiff base precursor from abundant and renewable lignin derivative vanillin and produced malleable thermosets (Schiff base covalent adaptable networks (CANs)) combining high performance, super-rapid reprocessability, excellent monomer recovery, and arbitrary permanent shape changeability as well as outstanding fire resistance. The Schiff base CANs exhibited high glass transition temperatures of ∼178 °C, tensile strength of ∼69 MPa, tensile modulus of ∼1925 MPa, excellent flame retardancy with UL-94 V0 rating and V1 rating, and high LOI of ∼30%. Meanwhile, three Schiff base CANs showed high malleability with the activation energy of the bond exchange of 49–81 kJ mol–1 and could be reprocessed in 2–10 min at 180 °C. These Schiff base CAN...

Naturally occurring iron oxide nanoparticles: morphology, surface chemistry and environmental stability

Abstract: The widespread nanostructures of iron oxides and oxyhydroxides are important reagents in many biogeochemical processes in many parts of our planet and ecosystem. Their functions in various aspects are closely related to their shapes, sizes, and thermodynamic surroundings, and there is much that we can learn from these natural relationships. This review covers these subjects of several phases (ferrihydrite, goethite, hematite, magnetite, maghemite, lepidocrocite, akaganeite and schwertmannite) commonly found in water, soils and sediments. Due to surface passivation by ubiquitous water in aquatic and most terrestrial environments, the difference in formation energies of bulk phases can decrease substantially or change signs at the nanoscale because of the disproportionate surface effects. Phase transformations and the relative abundance are sensitive to changes in environmental conditions. Each of these phases (except maghemite) displays characteristic morphologies, while maghemite appears frequently to inherit the precursor's morphology. We will see how an understanding of naturally occurring iron oxide nanostructures can provide useful insight for the production of synthetic iron oxide nanoparticles in technological settings.