Lin Lv

Hierarchical Configuration of NiCo2S4 Nanotube@Ni–Mn Layered Double Hydroxide Arrays/Three-Dimensional Graphene Sponge as Electrode Materials for High-Capacitance Supercapacitors

Three dimensional (3D) hierarchical network configurations are composed of NiCo2S4 nanotube @Ni-Mn layered double hydroxide (LDH) arrays in situ grown on graphene sponge. The 3D graphene sponge with robust hierarchical porosity suitable for as a basal growth has been obtained from a colloidal dispersion of graphene oxide using a simple directional freeze-drying technique. The high conductive NiCo2S4 nanotube arrays grown on 3D graphene shows excellent pseudocapacity and good conductive support for high-performance Ni-Mn LDH. The 3D NiCo2S4@Ni-Mn LDH/GS shows a high specific capacitance (Csp) 1740 mF cm(-2) at 1 mA cm(-2), even at 10 mA cm(-2), 1267.9 mF cm(-2) maintained. This high-performance composite electrode proposes a new and feasible general pathway as 3D electrode configuration for energy storage devices.

Hierarchical NiCo2S4@NiFe LDH Heterostructures Supported on Nickel Foam for Enhanced Overall-Water-Splitting Activity

Low-cost and highly efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are intensively investigated for overall water splitting. Herein, we combined experimental research with first-principles calculations based on density functional theory (DFT) to engineer the NiCo2S4@NiFe LDH heterostructure interface for enhancing overall water-splitting activity. The DFT calculations exhibit strong interaction and charge transfer between NiCo2S4 and NiFe LDH, which change the interfacial electronic structure and surface reactivity. The calculated chemisorption free energy of hydroxide (ΔEOH) is reduced from 1.56 eV for pure NiFe LDH to 1.03 eV for the heterostructures, indicating a dramatic improvement in OER performance, while the chemisorption free energy of hydrogen (ΔEH) maintains almost invariable. By the use of the facile hydrothermal method, NiCo2S4 nanotubes, NiFe LDH nanosheets, and NiCo2S4@NiFe LDH heterostructures are prepared on nickel foam, of which the corresponding experimental OER overpotentials are 306, 260, and 201 mV at 60 mA cm-2, respectively. These results are good agreement with the theoretical predictions. Meanwhile, the HER performance has little improvement, with an overpotential of about 200 mV at 10 mA cm-2. Due to the dramatic improvement in OER performance, there was an enhancement in the overall water-splitting activity of the NiCo2S4@NiFe LDH heterostructures, with a low voltage of 1.6 V.

Rational Design of Cobalt–Iron Selenides for Highly Efficient Electrochemical Water Oxidation

Exploring active, stable, earth-abundant, low-cost, and high-efficiency electrocatalysts is highly desired for large-scale industrial applications toward the low-carbon economy. In this study, we apply a versatile selenizing technology to synthesize Se-enriched Co1-xFexSe2 catalysts on nickel foams for oxygen evolution reactions (OERs) and disclose the relationship between the electronic structures of Co1-xFexSe2 (via regulating the atom ratio of Co/Fe) and their OER performance. Owing to the fact that the electron configuration of the Co1-xFexSe2 compounds can be tuned by the incorporated Fe species (electron transfer and lattice distortion), the catalytic activity can be adjusted according to the Co/Fe ratios in the catalyst. Moreover, the morphology of Co1-xFexSe2 is also verified to strongly depend on the Co/Fe ratios, and the thinner Co0.4Fe0.6Se2 nanosheets are obtained upon selenization treatment, in which it allows more active sites to be exposed to the electrolyte, in turn promoting the OER performance. The Co0.4Fe0.6Se2 nanosheets not only exhibit superior OER performance with a low overpotential of 217 mV at 10 mA cm-2 and a small Tafel slope of 41 mV dec-1 but also possess ultrahigh durability with a dinky degeneration of 4.4% even after 72 h fierce water oxidation test in alkaline solution, which outperforms the commercial RuO2 catalyst. As expected, the Co0.4Fe0.6Se2 nanosheets have shown great prospects for practical applications toward water oxidation.

Association of serum Dkk-1 levels with β-catenin in patients with postmenopausal osteoporosis

Wnt signaling plays an important role in the bone development and remodeling. The Wnt antagonist Dkk-1 is a potent inhibitor of bone formation. The aims of this study were firstly to compare the serum Dkk-1 levels in postmenopausal osteoporosis patients with age-matched healthy controls, and secondly, to assess the possible relationship between Dkk-1 and β-catenin, sclerostin, or bone turnover markers [CTX, PINP, N-MID-OT and 25(OH)D] in the setting of postmenopausal osteoporosis. A total of 350 patients with postmenopausal osteoporosis and 150 age-matched healthy controls were enrolled, and the serum levels of Dkk-1, β-catenin, sclerostin, OPG, and RANKL were detected by ELISA, and bone turnover markers [CTX, PINP, N-MID-OT and 25(OH)D] were measured by Roche electrochemiluminescence system in two groups. Serum Dkk-1 levels were significantly higher in postmenopausal osteoporosis group than in control group (P<0.001). Univariate analyses revealed that serum Dkk-1 levels were weakly negatively correlated to β-catenin (r=−0.161, P=0.003) and OPG (r=−0.106, P=0.047), while multiple regression analysis showed a negative correlation between serum Dkk-1 levels with β-catenin (β=−0.165, P=0.009) and BMD (β=−0.139, P=0.027), and a positive correlation between serum Dkk-1 levels and CTX (β=0.122, P=0.040) in postmenopausal osteoporosis group. No similar correlations ware observed in control group. The results provided evidence for the role of Dkk-1 in bone metabolism and demonstrated the link of Dkk-1 and Wnt/β-catenin in some ways.SummaryWnt signaling plays an important role in the bone development and remodeling. The Wnt antagonist Dkk-1 is a potent inhibitor of bone formation. The aims of this study were firstly to compare the serum Dkk-1 levels in postmenopausal osteoporosis patients with age-matched healthy controls, and secondly, to assess the possible relationship between Dkk-1 and β-catenin, sclerostin, or bone turnover markers [CTX, PINP, N-MID-OT and 25(OH)D] in the setting of postmenopausal osteoporosis. A total of 350 patients with postmenopausal osteoporosis and 150 age-matched healthy controls were enrolled, and the serum levels of Dkk-1, β-catenin, sclerostin, OPG, and RANKL were detected by ELISA, and bone turnover markers [CTX, PINP, N-MID-OT and 25(OH)D] were measured by Roche electrochemiluminescence system in two groups. Serum Dkk-1 levels were significantly higher in postmenopausal osteoporosis group than in control group (P<0.001). Univariate analyses revealed that serum Dkk-1 levels were weakly negatively correlated to β-catenin (r=−0.161, P=0.003) and OPG (r=−0.106, P=0.047), while multiple regression analysis showed a negative correlation between serum Dkk-1 levels with β-catenin (β=−0.165, P=0.009) and BMD (β=−0.139, P=0.027), and a positive correlation between serum Dkk-1 levels and CTX (β=0.122, P=0.040) in postmenopausal osteoporosis group. No similar correlations ware observed in control group. The results provided evidence for the role of Dkk-1 in bone metabolism and demonstrated the link of Dkk-1 and Wnt/β-catenin in some ways.

A Universal Method to Engineer Metal Oxide–Metal–Carbon Interface for Highly Efficient Oxygen Reduction

Oxygen is the most abundant element in the Earths crust. The oxygen reduction reaction (ORR) is also the most important reaction in life processes and energy converting/storage systems. Developing techniques toward high-efficiency ORR remains highly desired and a challenge. Here, we report a N-doped carbon (NC) encapsulated CeO2/Co interfacial hollow structure (CeO2-Co-NC) via a generalized strategy for largely increased oxygen species adsorption and improved ORR activities. First, the metallic Co nanoparticles not only provide high conductivity but also serve as electron donors to largely create oxygen vacancies in CeO2. Second, the outer carbon layer can effectively protect cobalt from oxidation and dissociation in alkaline media and as well imparts its higher ORR activity. In the meanwhile, the electronic interactions between CeO2 and Co in the CeO2/Co interface are unveiled theoretically by density functional theory calculations to justify the increased oxygen absorption for ORR activity improvement. The reported CeO2-Co-NC hollow nanospheres not only exhibit decent ORR performance with a high onset potential (922 mV vs RHE), half-wave potential (797 mV vs RHE), and small Tafel slope (60 mV dec-1) comparable to those of the state-of-the-art Pt/C catalysts but also possess long-term stability with a negative shift of only 7 mV of the half-wave potential after 2000 cycles and strong tolerance against methanol. This work represents a solid step toward high-efficient oxygen reduction.

Effect of Qing’e formula on circulating sclerostin levels in patients with postmenopausal osteoporosis

Serum sclerostin is positively associated with serum 25 hydroxyvitamin D concentration. Our preliminary studies confirmed that Qing’e formula (QEF) could effectively increase serum 25 hydroxyvitamin D concentration in patients with postmenopausal osteoporosis (PMOP), but the effect of supplementation with QEF on serum sclerostin is unknown. This study investigated the effects of supplementation of QEF on serum sclerostin levels in patients with PMOP. Totally 120 outpatients and inpatients with PMOP treated in our hospital between January and October 2012 were randomly divided into QEF+calcium group, alfacalcidol+calcium group, and placebo+calcium group (n=40 each), with a follow-up period of 2 years. The serum levels of sclerostin, 25 hydroxyvitamin D, and bone turnover markers (β-CTX, N-MID and T-PINP) at baseline and at the 6th month, 1st year, 1.5th year, and 2nd year after treatment were measured. The results showed that the levels of circulating sclerostin were increased significantly at the 6th month after treatment in QEF+calcium group and alfacalcidol+calcium group as compared with placebo+calcium group (P<0.05), but there was no significant difference between the former two groups (P>0.05). The levels of β-CTX, N-MID and T-PINP in serum were decreased in both QEF+calcium group and alfacalcidol+calcium group at the 6th month after treatment, without significant difference between the two groups (P>0.05). But the levels were significantly lower than that in placebo+calcium group (P<0.05). These results suggest that the mechanism by which QEF modulates bone metabolism in patients with PMOP might be related with the effect of QEF in increasing sclerostin expression. Our findings provide a scientific rationale for using QEF as an effective drug to prevent bone loss in PMOP.SummarySerum sclerostin is positively associated with serum 25 hydroxyvitamin D concentration. Our preliminary studies confirmed that Qing’e formula (QEF) could effectively increase serum 25 hydroxyvitamin D concentration in patients with postmenopausal osteoporosis (PMOP), but the effect of supplementation with QEF on serum sclerostin is unknown. This study investigated the effects of supplementation of QEF on serum sclerostin levels in patients with PMOP. Totally 120 outpatients and inpatients with PMOP treated in our hospital between January and October 2012 were randomly divided into QEF+calcium group, alfacalcidol+calcium group, and placebo+calcium group (n=40 each), with a follow-up period of 2 years. The serum levels of sclerostin, 25 hydroxyvitamin D, and bone turnover markers (β-CTX, N-MID and T-PINP) at baseline and at the 6th month, 1st year, 1.5th year, and 2nd year after treatment were measured. The results showed that the levels of circulating sclerostin were increased significantly at the 6th month after treatment in QEF+calcium group and alfacalcidol+calcium group as compared with placebo+calcium group (P<0.05), but there was no significant difference between the former two groups (P>0.05). The levels of β-CTX, N-MID and T-PINP in serum were decreased in both QEF+calcium group and alfacalcidol+calcium group at the 6th month after treatment, without significant difference between the two groups (P>0.05). But the levels were significantly lower than that in placebo+calcium group (P<0.05). These results suggest that the mechanism by which QEF modulates bone metabolism in patients with PMOP might be related with the effect of QEF in increasing sclerostin expression. Our findings provide a scientific rationale for using QEF as an effective drug to prevent bone loss in PMOP.