19 research outputs found

    Impact of immunosuppressant therapy on early recurrence of hepatocellular carcinoma after liver transplantation

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    Background/AimsThe most commonly used immunosuppressant therapy after liver transplantation (LT) is a combination of tacrolimus and steroid. Basiliximab induction has recently been introduced; however, the most appropriate immunosuppression for hepatocellular carcinoma (HCC) patients after LT is still debated.MethodsNinety-three LT recipients with HCC who took tacrolimus and steroids as major immunosuppressants were included. Induction with basiliximab was implemented in 43 patients (46.2%). Mycophenolate mofetil (MMF) was added to reduce the tacrolimus dosage (n=28, 30.1%). The 1-year tacrolimus exposure level was 7.2 ± 1.3 ng/mL (mean ± SD).ResultsThe 1- and 3-year recurrence rates of HCC were 12.9% and 19.4%, respectively. Tacrolimus exposure, cumulative steroid dosages, and MMF dosages had no impact on HCC recurrence. Induction therapy with basiliximab, high alpha fetoprotein (AFP; >400 ng/mL) and protein induced by vitamin K absence/antagonist-II (PIVKA-II; >100 mAU/mL) levels, and microvascular invasion were significant risk factors for 1-year recurrence (P<0.05). High AFP and PIVKA-II levels, and positive 18fluoro-2-deoxy-d-glucose positron-emission tomography findings were significantly associated with 3-year recurrence (P<0.05).ConclusionsInduction therapy with basiliximab, a strong immunosuppressant, may have a negative impact with respect to early HCC recurrence (i.e., within 1 year) in high-risk patients

    Simple neovaginoplasty using spontaneous regeneration ability of labial and vestibular flap in patients with MĂƒÂŒllerian agenesis

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    Objectives: This study is aimed to introduce a simple neovaginoplasty procedure without significant complications using the spontaneous regenerative ability of labial and vestibular advancement flaps in patients with MĂƒÂŒllerian agenesis. Materials and methods: Prospectively collected data of 5 patients with vaginal agenesis due to MĂƒÂŒllerian duct abnormality who underwent neovaginoplasty using labial and vestibular advancement flaps were retrospectively reviewed. Operative details, perioperative outcome, complications, length and width of the neovagina, and the postoperative sexual activity were evaluated. Results: The mean operation time was 48 min (range 30Ăą60 min) and the duration of follow-up ranged from 7 to 50 months. The mean length of the neovagina was 9.6 cm Ã 3.5 cm and 10.8 cm Ã 3.5 cm at hospital discharge and at final follow-up, respectively. No significant complications occurred during or after surgery. Epithelialization was completed by 8Ăą20 months and the time to first sexual intercourse ranged from 3 weeks to 27 months and none of the patients experienced any intercourse-related difficulties. Conclusion: Our neovaginoplasty technique using labial and vestibular advancement flap is simple, safe, minimally invasive and effective while avoiding the morbidity associated with other grafting techniques. Keywords: Labial advancement flaps, MĂƒÂŒllerian agenesis, Neovagina, Vaginoplast

    Effect of Ion Diffusion in Cobalt Molybdenum Bimetallic Sulfide toward Electrocatalytic Water Splitting

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    The electrocatalyst comprising two different metal atoms is found suitable for overall water splitting in alkaline medium. Hydrothermal synthesis is an extensively used technique for the synthesis of various metal sulfides. Time-dependent diffusion of the constituting ions during hydrothermal synthesis can affect the crystal and electronic structure of the product, which in turn would modulate its electrocatalytic activity. Herein, cobalt molybdenum bimetallic sulfide was prepared via hydrothermal method after varying the duration of reaction. The change in crystal structure, amount of Co–S–Mo moiety, and electronic structure of the synthesized materials were thoroughly investigated using different analytical techniques. These changes modulated the charge transfer at the electrode–electrolyte interface, as evidenced by electrochemical impedance spectroscopy. The Tafel plots for the prepared materials were investigated considering a less explored approach and it was found that different materials facilitated different electrocatalytic pathways. The product obtained after 12 h reaction showed superior catalytic activity in comparison to the products obtained from 4, 8, and 16 h reaction, and it surpassed the overall water splitting activity of the RuO2–Pt/C couple. This study demonstrated the ion diffusion within the bimetallic sulfide during hydrothermal synthesis and change in its electrocatalytic activity due to ion diffusion

    Effect of the Solvent Ratio (Ethylene Glycol/Water) on the Preparation of an Iron Sulfide Electrocatalyst and Its Activity towards Overall Water Splitting

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    The polyol method is an efficient procedure for metal sulfide preparation where polyol not only acts as a solvent but also as reducing and morphology‐modulating agent. Herein, iron sulfide particles were prepared via a modified polyol method by changing the ethylene glycol (EG) : water (H2O) ratio in the mixed solvent. Analytical techniques and electronic microscopy studies confirmed that the change in EG : H2O ratio modulated the crystal structure, morphology, and electronic structure of the prepared iron sulfide particles. The electrocatalytic activity of iron sulfide changed owing to these modulations. EG helped in the formation of a sheet‐like structure – a morphology that favours a higher accessibility to the catalytically active sites. As evidenced form electrochemical impedance studies, an increased electron density near the Fermi level, a faster substrate adsorption‐desorption rate at the active sites, and a faster charge transfer at the electrode‐electrolyte interface were the key factors for the amplification in catalytic activity. The prepared iron sulfide particles showed an overall water splitting efficiency that is comparable to that of the state‐of‐the‐art RuO2‐Pt/C couple in alkaline medium. This study shows the potential of the polyol method in the preparation and catalytic‐activity modulation of Fe−S‐based electrocatalysts

    Band gap modified boron doped NiO/Fe3O4 nanostructure as the positive electrode for high energy asymmetric supercapacitors

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    A boron doped NiO/Fe3O4 nanostructure was successfully synthesized by a facile one-step hydrothermal method. The boron doping was confirmed from the decreased band gap and increased electrical conductivity of the NiO/Fe3O4 composite. The Nyquist plot of the multimetal oxide was fitted with ZView software for detailed understanding of the effect of concentration of different metal oxides, boron doping and extensive charge–discharge cycles on the electrochemical properties of electrode materials. Very high specific capacitance of ∌1467 F g−1 was achieved as the synergistic effect of low activation energy and short ion diffusion path of the electrode materials. An asymmetric supercapacitor (ASS) was fabricated with the NiO/Fe3O4 composite and thermally reduced graphene oxide as the positive and negative electrode, respectively. The ASS showed a large specific capacitance of ∌377 F g−1 at a current density of 3 A g−1. Furthermore, the ASS showed a large energy density of ∌102.6 W h kg−1 and huge power density of ∌6300 W kg−1 and remained ∌82% stable even after 10 000 charge–discharge cycles. Therefore, a facile hydrothermal method was demonstrated to enhance the electrochemical properties of a multimetal oxide by boron doping for the development of next generation energy storage devices

    Optimization of Chemi‐adsorption, EDLC, and Redox Capacitance Through Electro‐precipitation Synthesis of Fe3O4/NiO@rGO/h‐BN for the Development of Hybrid Supercapacitor

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    3D Fe3O4/NiO was grafted on to the 2D rGO/h‐BN by electro‐precipitation method. Nitrogen of h‐BN moiety and oxygen functional groups of rGO played the role of negative active site to trap the metallic cations. Electrochemical charge storage mechanism was optimized by controlling the stoichiometry and defect contents of Fe3O4/NiO@rGO/h‐BN. Stoichiometry of the electro‐precipitated samples was tailored in presence of negative active sites of rGO/h‐BN and applied D.C. bias of the electrochemical bath. In addition, the nucleation and growth of metal oxides were influenced by the stacking and vacancy defects of rGO/h‐BN sheets. High specific capacitance (1328 F g−1) of Fe3O4/NiO@rGO/h‐BN was attributed to the synergistic effect of electrochemical double layer capacitance of rGO, chemi‐adsorption of –OH ions on Lewis acid (boron of h‐BN moiety) and redox capacitance of Fe3O4/NiO in alkaline medium. In addition, the presence of pyrrolic defect at the rGO/h‐BN stacking region acted as the nucleation site and provided additional redox capacitance by shifting the Fermi level towards the valance band. An asymmetric supercapacitor (ASC) was constructed using Fe3O4/NiO@rGO/h‐BN and thermally reduced GO as positive and negative electrode, respectively. ASC showed high energy (82 W h Kg−1) and power density (5600 W Kg−1) along with low relaxation time constant (2.2 ms) and high stability (79%) after 10,000 charge discharge cycles

    Cobalt Sulfide/Nickel Sulfide Heterostructure Directly Grown on Nickel Foam: An Efficient and Durable Electrocatalyst for Overall Water Splitting Application

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    Fabrication of high-performance noble-metal-free bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water is a promising strategy toward future carbon-neutral economy. Herein, a one-pot hydrothermal synthesis of cobalt sulfide/nickel sulfide heterostructure supported by nickel foam (CoSx/Ni3S2@NF) was performed. The Ni foam acted as the three-dimensional conducting substrate as well as the source of nickel for Ni3S2. The formation of CoSx/Ni3S2@NF was confirmed by X-ray diffraction and X-ray photoelectron spectroscopy. The formation of CoSx/Ni3S2@NF facilitated easy charge transport and showed synergistic electrocatalytic effect toward HER, OER, and overall water splitting in alkaline medium. Remarkably, CoSx/Ni3S2@NF showed catalytic activity comparable with that of benchmarking electrocatalysts Pt/C and RuO2. For CoSx/Ni3S2@NF, overpotentials of 204 and 280 mV were required to achieve current densities of 10 and 20 mA cm–2 for HER and OER, respectively, in 1.0 M KOH solution. A two-electrode system was formulated for overall water splitting reaction, which showed current densities of 10 and 50 mA cm–2 at 1.572 and 1.684 V, respectively. The prepared catalyst exhibited excellent durability in HER and OER catalyzing conditions and also in overall water splitting operation. Therefore, CoSx/Ni3S2@NF could be a promising noble-metal-free electrocatalyst for overall water splitting application

    Non-covalent functionalization of reduced graphene oxide using sulfanilic acid azocromotrop and its application as a supercapacitor electrode material

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    Sulfanilic acid azocromotrop (SAC) modified reduced graphene oxide (SAC-RGO) was prepared by simple non-covalent functionalization of graphene oxide (GO) followed by post reduction using hydrazine monohydrate. Spectral analysis (Fourier transform infrared, Raman and X-ray photoelectron spectroscopy) revealed that successful modification had occurred of GO with SAC through π–π interaction. The electrical conductivity of SAC-RGO was found to be ∌551 S m−1. The capacitive performance of SAC-RGO was recorded using a three electrode set up with 1 (M) aqueous H2SO4 as the electrolyte. The –SO3H functionalities of SAC contributed pseudocapacitance as evidenced from the redox peaks (at ∌0.43 and 0.27 V) present in the cyclic voltammetric (CV) curves measured for SAC-RGO. The contribution of electrical double layer capacitance was evidenced from the near rectangular shaped CV curves and resulted in a high specific capacitance of 366 F g−1 at a current density of 1.2 A g−1 for SAC-RGO electrode. An asymmetric device (SAC-RGO//RGO) was designed with SAC-RGO as the positive electrode and RGO as the negative electrode. The device showed an energy density of ∌25.8 W h kg−1 at a power density of ∌980 W kg−1. The asymmetric device showed retention in specific capacitance of ∌72% after 5000 charge–discharge cycles. The Nyquist data of the device was fitted with Z-view and different components (solution resistance, charge-transfer resistance and Warburg elements) were calculated from the fitted curves

    Superior performance of asymmetric supercapacitor based on reduced graphene oxide–manganese carbonate as positive and sono-chemically reduced graphene oxide as negative electrode materials

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    A novel strategy to synthesize hierarchical rod like MnCO3 on the reduced graphene oxide (RGO) sheets by a facile and cost-effective hydrothermal method is demonstrated. The chelating action of citric acid facilitates the formation a complex intermediate of Mn2+ and citrate ions, which finally results a 3D MnCO3/RGO (MRGO) composite with high electrical conductivity (∌1056 S m−1), good surface area (59 m2 g−1) and high pore volume (0.3 cm3 g−1). The specific capacitance (SC) of the MRGO composite is ∌1120 F g−1 at a current density of 2 A g−1 in three electrode system. An asymmetric device has been designed with MRGO as positive and sono-chemically reduced RGO (SRGO) as negative electrode material. The asymmetric device (MRGO//SRGO) shows the SC of ∌318 F g−1 (at 2 A g−1) and energy density of ∌113 W h kg−1 (at 1600 W kg−1). The true energy density (1.7 W h kg−1) has been calculated considering the total weight of the device. The MRGO//SRGO device can power a wall clock for ∌13 min after full charging. The Nyquist plot of the asymmetric cell has been simulated with Z-View software to measure the solution resistance, charge-transfer resistance and Warburg elements
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