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A woven carbon fiber (WCF)-based triboelectric nanogenerator (TENG)-cum-structural supercapacitor is an excellent multifunctional device for clean energy harvesting and storage. This type of device has high load-bearing capacity and functions smoothly under severe outdoor conditions. Herein, WCF-based multifunctional TENG is reported that generated 8.9 W m−2 power with 84% energy conversion efficiency. The energy generated by the TENG was simultaneously stored in a connected supercapacitor that provide 1.93 Wh kg−1 of energy density and delivers 39.23 W kg−1 of power density. The specific surface area of the WCF was enhanced several hundred-fold by coating with an N-doped Zn–Cu selenide nanoporous material, thereby enabling higher energy generation and elevated storage capacity of the device. The TENG use a polyester-based solid polymer electrolyte as the negative electrode and polydimethylsiloxane-coated WCF as the positive electrode. The device has a very high coulombic efficiency with high mechanical strength and ability to resist massive impact. An application of the multifunctional device was demonstrated. These types of multifunctional devices have great potential in the self-charging automobile, aerospace, sensor, and electronics sectors.

Silicon microparticles (SiMPs), which have a high capacity, a high initial Coulombic efficiency, and a low volume-to-surface ratio compared with nanosized materials, are promising anode materials f...

To boost the photoelectrochemical water oxidation performance of hematite photoanodes, high temperature annealing has been widely applied to enhance crystallinity, to improve the interface between the hematite-substrate interface, and to introduce tin-dopants from the substrate. However, when using additional dopants, the interaction between the unintentional tin and intentional dopant is poorly understood. Here, using germanium, we investigate how tin diffusion affects overall photoelectrochemical performance in germanium:tin co-doped systems. After revealing that germanium is a better dopant than tin, we develop a facile germanium-doping method which suppresses tin diffusion from the fluorine doped tin oxide substrate, significantly improving hematite performance. The NiFeOx@Ge-PH photoanode shows a photocurrent density of 4.6 mA cm−2 at 1.23 VRHE with a low turn-on voltage. After combining with a perovskite solar cell, our tandem system achieves 4.8% solar-to-hydrogen conversion efficiency (3.9 mA cm−2 in NiFeOx@Ge-PH/perovskite solar water splitting system). Our work provides important insights on a promising diagnostic tool for future co-doping system design., Germanium (Ge) has potential as a dopant suitable for the hematite-based photoelectrochemical water splitting system. Here, the authors report the fabrication of Ge doped porous hematite and demonstrate an efficient tandem system of Ge doped porous hematite and the perovskite solar cell.

Molybdenum disulfide (MoS2) is considered a promising material in energy storage systems, and is thus drawing considerable attention. However, the relatively low conductivity of bulk MoS2 has been a threat for practical applications. This study developed a simple and scalable fabrication method of few-layer MoS2 sheets embedded in a nanoporous graphene film (NGF) as a high capacitance active material. Transfer of MoS2/NGF onto a flexible substrate followed by plotter cutting produced a highly efficient micro-supercapacitor with superior flexibility, mechanical stability, and great potential for applications in wearable electronics. Notably, MoS2/NGF-based mSC revealed a high volumetric capacitance of 55 F cm−3 and 82.2% of capacitance retention after 20 000 cycles, which are superior to the reported data for solid-state micro-supercapacitors. With these performances, the flexible MoS2/NGF mSC exhibited an ultrahigh energy density of 7.64 mW h cm−3 and power density of 9.96 W cm−3 in a H3PO4 gel polymer electrolyte. The high volumetric capacitance and energy/power densities of MoS2/NGF as micro-supercapacitor electrodes are due to direct growth of ultra-thin MoS2 onto the interconnected 3D nanoporous graphene film with extended active sites and good conductivity. The MoS2/NGF mSC integrated on the skin efficiently powered a light emitting diode and strain sensors. This work suggests a meaningful way to realize film type MoS2 active materials in flexible micro-supercapacitors for wearable applications.

We report a Co3O4 exsolved perovskite oxide PrBaMn1.7Co0.3O5+δ (Co3O4–PBMCO) that utilizes the Faradaic transfer of metal oxide and favorable OH– adsorption for an energy storage mechanism, as an a...

Reduced graphene oxide (rGO) composites for energy-related applications have attracted increasing attention. However, previous studies on rGOs still showed limitations because of unresolved several...

The photoelectrochemical performance of a co-doped hematite photoanode might be hindered due to the unintentionally diffused Sn from a fluorine-doped tin oxide (FTO) substrate during the high-temperature annealing process by providing an increased number of recombination centers and structural disorder. We employed a two-step annealing process to manipulate the Sn concentration in co-doped hematite. The Sn content [Sn/(Sn + Fe)] of a two-step annealing sample decreased to 1.8 from 6.9% of a one-step annealing sample. Si and Sn co-doped hematite with the reduced Sn content exhibited less structural disorder and improved charge transport ability to achieve a 3.0 mA cm-2 photocurrent density at 1.23 VRHE, which was 1.3-fold higher than that of the reference Si and Sn co-doped Fe2O3 (2.3 mA cm-2). By decorating with the efficient co-catalyst NiFe(OH)x, a maximum photocurrent density of 3.57 mA cm-2 was achieved. We further confirmed that the high charging potential and poor cyclability of the zinc-air battery could be dramatically improved by assembling the optimized, stable, and low-cost hematite photocatalyst with excellent OER performance as a substitute for expensive Ir/C in the solar-assisted chargeable battery. This study demonstrates the significance of manipulating the unintentionally diffused Sn content diffused from FTO to maximize the OER performance of the co-doped hematite.

An efficient reduction method to obtain high-quality graphene sheets from mass-producible graphene oxide is highly desirable for practical applications. Here, we report an in situ deoxidation and graphitization mechanism for graphene oxide that allows for high-quality reduced graphene oxide sheets under the low temperature condition (

The aim of this study was to compare chemical properties and bioactivities of with mineral trioxide aggregate (MTA) and EndoSequence Root Repair Material (ERRM). After setting, surfaces of test materials were observed by scanning electron microscope (SEM). The pH and cell viability of materials were tested. Osteoblastic differentiation and alkaline phosphatase (ALP) activity were measured by quantitative real-time PCR and ALP staining. MTA showed spindle-shaped crystals while ERRM showed round-shaped crystals of various sizes. ERRM presented lower pH than MTA. Both materials showed good cell viabilities compared to the control. Expression levels of osteoblastic genes and ALP staining were increased significantly (p

Although mineral trioxide aggregates (MTA) have been adopted as an endodontic sealer because of excellent sealing effect and bioactive property and been modified with improvement of its characteristics, the developed MTA sealers have not yet satisfied all the ideal requirements of endodontic sealers. The aim of this study was to assess the characteristics of elastin-like polypeptide (ELP)-incorporated MTA for use as an endodontic sealer and compare them with those of commercial MTA sealers. Two commercial MTA sealers and three experimental ELP-incorporated MTA sealers with 0.3, 0.4, and 0.5 liquid/powder (L/P) ratio for 10 wt% ELP liquid were evaluated. The push-out bond strength, flow rate, sealer penetrability and wash-out resistance were tested and the sealer-dentin interface was observed using a scanning electron microscope (SEM). Our study revealed the ELP-incorporated MTA sealer, especially in 0.4 L/P ratio, exhibited the higher push-out bond strength and flow rate (P

To boost the photoelectrochemical water oxidation performance of a hematite photoanode, high temperature annealing has been widely applied to enhance crystallinity and remove the physical interface between the hematite and the fluorine doped thin oxide (FTO) substrate. However, the high temperature also results in unintentional Sn-doping due to thermal diffusion from the bottom FTO substrate. Therefore, when using additional dopants and the subsequent high temperature annealing process to enhance performance, the procedure should more precisely be considered co-doping of the hematite photoanode. However, at present, the interaction between the unintentional Sn and intentional dopant is poorly understood. Here, using germanium (Ge), which has been proven a promising dopant in previously reported simulations, we investigated how Sn diffusion affects overall PEC performance in Sn:Ge co-doped systems. After revealing the negative interaction of Sn and Ge dopants, we developed a facile Ge-doping method which suppresses Sn diffusion from the FTO substrate, significantly improving hematite performance. The Sn:Ge-hematite photoanode showed a photocurrent density of 4.6 mA cm− 2 at 1.23 VRHE with an excellent low turn-on voltage. After combining with a perovskite solar cell, our tandem system achieved outstanding 4.8% solar-to-hydrogen conversion efficiency (3.9 mA cm− 2 in an unassisted water splitting system). Our work provides important insights on a promising diagnostic tool for future co-doping system design.

Doping engineering is of key importance for controlling the electrical, optical and structural properties of the semiconductor. Doping of hematite (α-Fe 2 O 3 ) with heteroatoms is especially essential to boost its poor electrical properties for enhanced photocatalytic water splitting. For some impurities that create an unfavorable thermodynamic equilibrium, doped hematite with a reasonable water splitting performance needs to be synthesized under elaborate experimental conditions, which severely restricts the realization of hydrogen economy. Here we show that the high formation energy of a Si-doped hematite can be decreased with the introduction of a host Ti-dopant via a thermodynamically favorable equilibrium process, making easy and cost-efficient solution-based Si-doping possible. By taking advantage of formation energy control, we achieved a photocurrent density of 5.7 mA cm -2 at 1.23 V RHE in the optimized Si-doped hematite (Si:Ti-hematite) without using any noble metal or demanding experimental processes. Our study suggests a ground rule for the facile injection of the high-formation energy dopant into photocatalysts, which can be readily extended to other doped systems to achieve a substantial improvement in PEC performance.

To realize the full performance of Zn-air batteries, the co-presence of a highly efficient oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER) in the system is critical. Although copper and nickel are known to be bifunctional catalysts for ORR and OER, sluggish reactions as a result of the exceptionally strong O=O bond on the metal surface make it difficult to achieve high system efficiency. In this study, a metal carbide layer (CuCx and NiCx ) on dendritic copper and nickel is fabricated by a facile electrodeposition process to provide efficient catalytic active sites with moderate binding energy for easy electron transfer in both the OER and the ORR. The dendritic structure provides an enriched catalytic surface and the protective metal carbide layer offers an appropriate O binding energy and durability of Zn-air batteries. Owing to the presence of the stable metal carbide surface on the dendritic metal, the CuCx /Cu and NiCx /Ni catalysts exhibited well-defined limiting current densities of -5.19 and -5.11 mA cm-2 , respectively, and improved ORR and OER activities with lower polarization than the corresponding metal catalysts. Density functional theory revealed a 0.74 eV decrease in the overpotential of NiCx /Ni-catalyzed OER reactions compared with Ni-catalyzed OER reactions. The experimental and theoretical results prove that carbide layers on dendritic metal surfaces can greatly improve the activity of ORR and OER bifunctional electrocatalysts for Zn-air batteries.

A carbon electrode was designed to guarantee flexibility of symmetric electric double layer capacitors (EDLCs) based on its architecture. Three different dimensional carbon materials were combined ...

We report that metal ions (M: Sn4+ and Ti4+) and boron-codoped hematite photoanodes with an n–n+ homojunction showed significantly increased photoelectrochemical (PEC) water splitting activity with...

Graphene-based materials are an attractive lithium storage material for next-generation lithium-based batteries due to its high capacity, surface area and conductivity. However, one of the major problems for its broad application in batteries is a large irreversible capacity, and the poor cycle stability and low rate capability remain. Here, we report a MoS2-stabilized hierarchical three-dimensional graphene-based nanostructure, in which the MoS2 layer acts as a stabilizer as well as an active material. We show that the presence of MoS2 thin layer adjacent to the graphene surface can improve lithium storage capability by improving lithium ion diffusion property with fast Li-ion transport kinetic. On the basis of experimental and theoretical approaches, we ascribe the improved reversible lithium storage to the unusual reversible Li-MoS2 redox reaction and charge distribution on the graphene and MoS2 interlayers. These findings will provide a potential new direction in the design of electrode materials for advanced lithium storage technologies.

We introduce the use of xurography as a facile plotter-assisted integration technique for an all-solid-state flexible micro-supercapacitors (mSCs), which is cost-effective and time-saving, by which 162 mSCs can be simultaneously produced on an A4 sized PET film. 3D-graphene networks (3DGNs) grown on a SiO2 template exhibited large surface area and outstanding electrical conductivity as active materials for mSCs due to the interconnected 3D structure. By simply mixing SWNTs and Ag NWs with 3DGNs, an excellent specific areal capacitance of 19 mF cm−2 was obtained from an as-prepared 3DGN/SWNT/AgNW mSC on a flexible substrate and 84% of the initial capacitance was maintained after 10,000 cycles. The device exhibited stable electrochemical performances under various deformation conditions. The subsequent transfer onto a textile further allowed the fabrication of a wearable particle detector, which confirmed a practical application of a mSC with good performance integrated via a plotter-assisted technique.

Utilizing the broad-band solar spectrum for sea water desalination is a promising method that can provide fresh water without sophisticated infrastructures. However, the solar-to-vapour efficiency has been limited due to the lack of a proper design for the evaporator to deal with either a large amount of heat loss or salt accumulation. Here, these issues are addressed via two cost-effective approaches: I) a rational design of a concave shaped supporter by 3D-printing that can promote the light harvesting capacity via multiple reflections on the surface; II) the use of a double layered photoabsorber composed of a hydrophilic bottom layer of a polydopamine (PDA) coated glass fiber (GF/C) and a hydrophobic upper layer of a carbonized poly(vinyl alcohol)/polyvinylpyrrolidone (PVA/PVP) hydrogel on the supporter, which provides competitive benefit for preventing deposition of salt while quickly pumping the water. The 3D-printed solar evaporator can efficiently utilize solar energy (99%) with an evaporation rate of 1.60 kg m-2 h-1 and efficiency of 89% under 1 sun irradiation. The underlying reason for the high efficiency obtained is supported by the heat transfer mechanism. The 3D-printed solar evaporator could provide cheap drinking water in remote areas, while maintaining stable performance for a long term.

The demand for portable electronic devices is driving the development of flexible supercapacitor, while current devices still need to improve the performance for practical applications. Here, we report a cost-efficient flexible three-dimensional-Ni (3D-Ni) electrode for a flexible supercapacitor with excellent energy density and power density. The meso-porous 3D-Ni electrode provides a large number of active sites to store charges and good accessibility to the ions in polymer electrolytes, leading to excellent capacitance, high energy density, as well as high power density. The Ni(OH)2/3D-Ni positive electrode showed an outstanding specific capacitance of ~3400 F/g at 10 A/g and retained 80% of the initial capacitance at 200 A/g. The negative MnO2/3D-Ni electrode exhibited a specific capacitance of 1250 F/g at 10 A/g and excellent capacitance retention of 82% at 200 A/g. The Ni(OH)2/3D-Ni//MnO2/3D-Ni hybrid supercapacitor delivered an excellent energy density of 75 Wh/kg and a high power density of 5.3 kW/kg, and these values did not change under bending conditions. The 3D-Ni electrode introduced here represents a new type of ideal electrode that can be easily applied to various flexible/wearable electronic device with excellent performance.

We present a facile yet efficient single-step pyrolysis method to prepare bulk-scale high-performance N-doped 3D-graphitic foams with various length-scale pores. The iron precursors act as catalysts for the conversion of organic substances to a graphitic structure while simultaneously providing a rigid template that prevents the aggregation of organic components, and soluble polymers act as a carbon source for the formation of N-doped multilayer graphene under high-temperature and inert conditions. The 3D-graphitic foams possess highly interconnected networks composed of micro-, meso-, and macropores with a specific surface area of up to 1509 m2 g–1 and a high conductivity of 10 S m–1. The resulting 3D-graphitic foams exhibited specific capacitance values of 330 and 242 F g–1 with outstanding cycling stability (a 23% loss after 100 000 cycles for a symmetric cell) in a three-electrode system and in a symmetric cell, respectively, when used as active materials in a supercapacitor. This study suggests the g...

We report a three-dimensional graphene network decorated with nickel nanoparticles as a current collector to achieve outstanding performance in Ni(OH)2-based supercapacitors with excellent energy density. A cost-efficient and single-step fabrication method creates nickel-particle decorated three-dimensional graphene networks (Ni–GNs) with an excellent electrical conductivity of 107 S m−1 and a surface area of 16.4 m2 g−1 that are superior to those of carbon alternatives and commercial 3D-Ni foam, respectively. The supercapacitor in which Ni(OH)2 active materials are deposited on Ni–GNs exhibited an outstanding capacitance value of 3179 F g−1 at 10 A g−1 in a three-electrode system and 90% of capacitance retention after 10 000 cycles. Furthermore, it showed an outstanding energy density of 197.5 W h kg−1 at a power density of 815.5 W kg−1 when tested in a two-electrode system. To the best of our knowledge, our device realized the world record value of energy density with a high rate capability and good cycle stability among Ni(OH)2-based supercapacitors. The excellent electrical properties of easily synthesized Ni–GNs as the ideal current collector clearly suggest a straightforward way to achieve great performance supercapacitors with both high energy density and power density.

Realization of a highly flexible, lightweight, and high performance flexible supercapacitor was achieved using three-dimensional graphene on flexible graphite-paper. A simple and fast self-assembly approach was utilized for the uniform deposition of chemical vapor deposition (CVD)-grown high quality 3D-graphene powders on a flexible graphite-paper substrate. The fabricated paper-based symmetric supercapacitor exhibited a maximum capacitance of 260 F g −1 (15.6 mF cm −2 ) in a three electrode system, 80 F g −1 (11.1 mF cm −2 ) in a full cell, high capacitance retention and a high energy density of 8.8 Wh kg −1 (1.24 μWh cm −2 ) at a power density of 178.5 W kg −1 (24.5 μW cm −2 ). The flexible supercapacitor maintained its supercapacitor performance well, even under bent, rolled, or twisted conditions, signifying the excellent flexibility of the fabricated device. Our straightforward approach to the fabrication of highly flexible and lightweight supercapacitors offers new design opportunities for flexible/wearable electronics and miniaturized device applications that require energy storage units that meet the demands of the multifarious applications.

SUMMARY The aim of this randomized controlled clinical trial was to compare the clinical effectiveness of different polishing systems and self-etch adhesives in class V composite resin restorations. A total of 164 noncarious cervical lesions (NCCLs) from 35 patients were randomly allocated to one of four experimental groups, each of which used a combination of polishing systems and adhesives. The two polishing systems used were Sof-Lex XT (Sof), a multistep abrasive disc, and Enhance/Pogo (EP), a simplified abrasive-impregnated rubber instrument. The adhesive systems were Clearfil SE bond (CS), a two-step self-etch adhesive, and Xeno V (XE), a one-step self-etch adhesive. All NCCLs were restored with light-cured microhybrid resin composites (Z250). Restorations were evaluated at baseline and at 6, 12, 18, and 24 months by two blinded independent examiners using modified FDI criteria. The Fisher exact test and generalized estimating equation analysis considering repeated measurements were performed to compare the outcomes between the polishing systems and adhesives. Three restorations were dislodged: two in CS/Sof and one in CS/EP. None of the restorations required any repair or retreatment except those showing retention loss. Sof was superior to EP with regard to surface luster, staining, and marginal adaptation (p0.05). Sof is clinically superior to EP for polishing performance in class V composite resin restoration. XE demonstrates clinically equivalent bonding performance to CS.

Vertically aligned iron oxide nanowire arrays were successfully synthesized via a cost-efficient maskless top-down approach. High density nanowires are formed by simple oxygen reactive ion etching of an iron-containing polymer film without any artificial mask. Highly crystalline hematite nanowires with a diameter of 38–45 nm and a high aspect ratio of 131 are uniformly produced over large areas after calcination. The high density graphene/magnetite nanostructure created by pyrolyzing iron oxide/organic nanowires with three-dimensional morphology provided highly enhanced Raman scattering with an enhancement factor of up to 7.0 × 104 due to trapping of the absorbed light in the three-dimensional graphene forest. Our maskless top-down approach to fabricate iron oxide nanowires offers unique advantages of a solution-based process to easily overcome the limit in the morphology and substrate-dependent properties of nanowire synthesis. This technique may have excellent practical potential as a simple, rapid, and reproducible process for the fabrication of high density and high aspect ratio iron oxide nanowires that are useful in various applications.

This is the first report on the fabrication of defect-free submicron structures with more than 100 μm thickness and an aspect ratio over 100. Highly transparent poly(glycidyl methacrylate-co-acryloisobutyl POSS) (PGP) was synthesized via radical polymerization. The mechanical properties of the PGP submicron structure displayed a Young's modulus of 6.09 GPa and a hardness of 0.16 GPa, 4.2 and 8 times, respectively, than those of SU8 nanopatterns. These enhancements enable the utilization of ultrathick 2D-/3D-submicron structures as an ideal platform for microelectromechanical systems, big data storage systems, energy devices, etc.

Highlights The flexible 3D porous structure with a large surface area provides pathways for rapid ion/electron transport and ion diffusion as well as numerous electroactive sites.The wire-shaped supercapacitor exhibits a high energy density of 153.3 Wh kg−1 and a power density of 8810 W kg−1.The hybrid device demonstrates excellent durability under various mechanical deformations. Electronic supplementary material The online version of this article (10.1007/s40820-019-0356-z) contains supplementary material, which is available to authorized users., We report a wire-shaped three-dimensional (3D)-hybrid supercapacitor with high volumetric capacitance and high energy density due to an interconnected 3D-configuration of the electrode allowing for large number of electrochemical active sites, easy access of electrolyte ions, and facile charge transport for flexible wearable applications. The interconnected and compact electrode delivers a high volumetric capacitance (gravimetric capacitance) of 73 F cm−3 (2446 F g−1), excellent rate capability, and cycle stability. The 3D-nickel cobalt-layered double hydroxide onto 3D-nickel wire (NiCo LDH/3D-Ni)//the 3D-manganese oxide onto 3D-nickel wire (Mn3O4/3D-Ni) hybrid supercapacitor exhibits energy density of 153.3 Wh kg−1 and power density of 8810 W kg−1. The red light-emitting diode powered by the as-prepared hybrid supercapacitor can operate for 80 min after being charged for tens of seconds and exhibit excellent electrochemical stability under various deformation conditions. The results verify that such wire-shaped 3D-hybrid supercapacitors are promising alternatives for batteries with long charge–discharge times, for smart wearable and implantable devices. Electronic supplementary material The online version of this article (10.1007/s40820-019-0356-z) contains supplementary material, which is available to authorized users.

Nickel-titanium (NiTi) rotary files have enabled efficient root canal preparations that maintain the canal center with fewer aberrations compared to hand files. However, NiTi rotary files are susceptible to fracture, which can thereby compromise root canal treatment. Therefore, NiTi files have been developed to enhance fracture resistance by modifying design and thermal treatment. The objective of this study was to compare the torsional fatigue resistance and bending resistance of NiTi files manufactured from different alloys and treatments. ProTaper NEXT X2 (PTN; M-wire), V taper 2H (V2H; controlled memory wire), NRT (heat-treated), and One Shape (OS; conventional alloy) instruments of tip size #25 were compared. Torsional fatigue was evaluated by embedding the 3 mm tip of each instrument (N = 10/brand) in resin and the repetitive application of torsional stress (300 rpm, 1.0 N·cm) by an endodontic motor with autostop when the file fractured. The number of loading cycles to fracture was recorded and analyzed by Kruskal–Wallis and Mann–Whitney U tests with Bonferroni’s correction. Bending resistance of the instruments was tested using a cantilever bending test to the 3 mm point from the tip (N = 10/brand). The stress was measured when deflection of 3 mm was subjected and statistically analyzed with a one-way analysis of variance and Tukey’s honest significance difference test (α = 0.05). V2H withstood the highest number of load applications during torsional fatigue testing (p<0.05), followed by NRT, PTN, and OS, where the differences between NRT and PTN (p=0.035) and between PTN and OS (p=0.143) were not statistically significant. V2H showed the lowest bending stiffness, followed by NRT, PTN, and OS (p<0.001). Thermal treatment of NiTi wire resulted in improved mechanical properties, and controlled memory wire provided improved flexibility and torsional fatigue resistance.

The purpose of this study is to assess the effect of autoclave sterilization on the cyclic fatigue and torsional fracture resistance of ProTaper Universal (PTU), K3XF, HyFlex EDM (EDM), and TF adaptive (TFA). Sixty instruments from each file type were divided into two categories for cyclic fatigue group (CGr) and torsional fracture group (TGr). CGr and TGr were divided into three subgroups, respectively, consisting of ten instruments from each file type. Cyclic fatigue fracture test was performed using artificial canal made of stainless steel, and the mean number of cycles to failure (NCF) were determined. CGr1, the files were tested to establish baseline for NCF; CGr2, the files were tested cyclic fatigue after 10 cycles of autoclave; CGr3, instruments were autoclaved after being cycled to 25, 50, and 75% of corresponding NCF determined in CGr1, followed by cyclic fatigue test. The torsional fracture test was performed without autoclave (TGr1), after 3-cycle autoclave (TGr2), and 7-cycle autoclave (TGr3), respectively, which evaluated maximum torque and angular deflection. NCF, maximum torque and angular deflection were compared using one-way ANOVA with Bonferroni test. Two-way ANOVA was performed to determine the interaction between 'autoclave treatment' and 'type of NiTi file'. EDM showed highest NCF within the same autoclave treatment. TFA presented the lowest maximum torque and the highest angular deflection, and PTU presented the lowest angular deflection. Within the same NiTi file systems, most of NCF, maximum torque and angular deflection of tested files were not significantly influenced by autoclave condition.

This study introduces an in situ fabrication of nanoporous hematite with a Ti-doped SiOx passivation layer for a high-performance water-splitting system. The nanoporous hematite with a Ti-doped SiOx layer (Ti-(SiOx /np-Fe2 O3 )) has a photocurrent density of 2.44 mA cm(-2) at 1.23 VRHE and 3.70 mA cm(-2) at 1.50 VRHE . When a cobalt phosphate co-catalyst was applied to Ti-(SiOx /np-Fe2 O3 ), the photocurrent density reached 3.19 mA cm(-2) at 1.23 VRHE with stability, which shows great potential of the use of the Ti-doped SiOx layer with a synergistic effect of decreased charge recombination, the increased number of active sites, and the reduced hole-diffusion pathway from the hematite to the electrolyte.

Supercapacitors are known to suffer from relatively low energy density and stability, which hampers their substitution for existing batteries. Here, we report an outstanding positive electrode platform for supercapacitor having both high energy density and high power density as well as good stability, by fabricating a low resistance Ohmic contact between Ni(OH)2 active materials and a 3-D current collector, nanoporous gold (NPG). The Ni(OH)2/NPG electrode was optimized by finely adjusting the portion of two different parts of the deposited Ni(OH)2, one part in direct contact with the NPG and the other part on top of the NPG. The optimized Ni(OH)2/NPG electrode exhibited 2223 F/cm3 of volumetric capacitance (considering both the active material and the current collector) at a current density of 5 A/g, values which are beyond the theoretical capacitance value, and the device retained 90% capacitance of the initial value at 500 A/g and after 30,000 cycles, respectively. This electrode showed an excellent energy density of 98 Wh/kg and power density of 50 kW/kg in a Ni(OH)2/NPG//MnO2/NPG two electrode supercapacitor system. The excellent performance of the Ni(OH)2/NPG electrode is attributed not only to the increased surface area of the Ni(OH)2 active materials, but also to the favorable path for charge transport created between the Ni(OH)2 and the gold electrode due to the presence of Ohmic contact, which eventually leads to the good kinetic properties and good stability.

We report an efficient Ti-doped FeOOH (Ti-FeOOH) co-catalyst applied on SiOx thin layer coated Ti-doped porous Fe2O3 (Ti-PH) to realize an excellent water splitting photoelectrochemical cell. The SiOx thin layer coated on Ti-doped porous hematite induces preferential deposition of the Ti-FeOOH co-catalyst on the inner pores of Ti-PH, which enhances oxygen evolution reaction performance without interrupting the absorption of light by hematite. The photocurrent density of Ti-FeOOH/Ti-PH is 4.06 mA cm−2 at 1.23 V vs. RHE, 3.4 times higher than that of conventional worm-like hematite, with excellent long-term stability for 36 h. This represents the state-of-the-art performance among hematite-based systems with the exception of very few studies that used precious materials. Importantly, the proposed photoanode can be fabricated by a simple and cost-efficient solution-based method, i.e. with cheap precursors and without any specific equipment.

Capacitive deionization (CDI) has attracted immense attention in recent years due to its simple energy efficient and eco-friendly desalination process. In capacitive deionization research, limited scale of fabrication for active materials and improving desalination efficiency have been the major challenges. Herein, micro-meso-macroporous three-dimensional graphene (MMM-3DG) with a high surface area (1492.8 m2 g−1) was fabricated in gram-scale production (>1.0 g per one time) as an effective active material for CDI. MMM-3DG exhibited a high electrosorption capacity (9.37 mg g−1) and a fast electrosorption rate (2.79 mg g−1 min−1). Furthermore, MMM-3DG delivered an outstanding rate constant value of 0.071 by a pseudo-second-order kinetic model, and thus low energy consumption value per desalinating ion (33.17 kJ mol−1) during the adsorption process.

A tandem system consisting of a combined hematite photoanode/perovskite solar cell is a novel configuration enabling unbiased solar-driven water splitting in a cost-efficient way. However, similar light absorption spectrums between hematite and perovskite, causing significant optical loss of the solar cell located behind the photoelectrochemical cell, have been a critical issue, resulting in a substantial reduction in the overall photoelectrochemical performance in the bias-free tandem system. Herein, we report an efficient thin film hematite/perovskite tandem cell optimized with consideration of both quantum efficiency of the hematite photoanode and optical loss of the solar cell. Ti,Si co-doping with controlled dopability and deposition of transparent NiFeOx co-catalyst on hematite (NiFeOx@Ti:Si–Fe2O3(t)) allowed for highly improved surface reaction kinetics and charge transport behaviors, endowing our thin film with state-of-the-art performance among thin film hematite photoanodes reported to date, with a photocurrent density of 2.62mAcm−2 at 1.23VRHE and an onset potential of 0.71V. The perovskite solar cell in the thin hematite/solar cell exhibited an anodic shift of Voc from 1.08V to 1.16V and a three-fold increased photocurrent density (15.5mAcm−2) compared to the solar cell of the conventional thick hematite/solar cell system. The assembled dual photoanodes (dual NiFeOx@Ti:Si–Fe2O3) reached a maximum photocurrent density of 4.0mAcm−2 at 1.23VRHE. Our tandem photoelectrochemical system comprising assembled dual thin film NiFeOx@Ti:Si–Fe2O3/solar cell showed outstanding performance of an unbiased solar-to-hydrogen (STH) conversion efficiency of 4.49%, which is the highest recorded value in the hematite/perovskite tandem cell systems. This work provides a great potential for further development of an unassisted solar water splitting system with the thin film hematite.

This study evaluates the effects of various agitation methods on the adhesive layer formation of a new HEMA-free universal dentin adhesive. The µTBS of the universal adhesive, G-Premio BOND in the self-etch mode was evaluated using three agitation methods [passive agitation (PA), active agitation (AA), ultrasonic agitation (UA)], with and without aging treatment. Two-way analysis of variance revealed that aging treatment was not a statistically significant factor. Tukey's HSD test showed significant differences based on the application method, UA>AA>PA. TEM images of the PA group revealed multiple water blisters in the adhesive layers; AA and UA groups presented significantly less or no blisters within the adhesive layers; thus, AA and UA groups exhibited better bonding performance for the HEMA-free universal adhesive. It is assumed that the entrap ped blisters can be reduced with the active application of dentin adhesive, and thus improving the bonding performance.

Solar desalination via thermal evaporation of seawater is one of the most promising technologies for addressing the serious problem of global water scarcity because it does not require additional supporting energy other than infinite solar energy for generating clean water. However, low efficiency and a large amount of heat loss are considered critical limitations of solar desalination technology. The combination of mesoporous three-dimensional graphene networks (3DGNs) with a high solar absorption property and water-transporting wood pieces with a thermal insulation property has exhibited greatly enhanced solar-to-vapor conversion efficiency. 3DGN deposited on a wood piece provides an outstanding value of solar-to-vapor conversion efficiency, about 91.8%, under 1 sun illumination and excellent desalination efficiency of 5 orders salinity decrement. The mass-producible 3DGN enriched with many mesopores efficiently releases the vapors from an enormous area of the surface by heat localization on the top surface of the wood piece. Because the efficient solar desalination device made by 3DGN on the wood piece is highly scalable and inexpensive, it could serve as one of the main sources for the worldwide supply of purified water achieved via earth-abundant materials without an extra supporting energy source.

By creating a p–n heterojunction of molybdenum sulfide (MoSx)/Ti-doped Fe2O3 (Ti-Fe2O3), we successfully addressed electron–hole transfer problems of hematite and thus achieved the enhanced photoelectrochemical (PEC) performance. MoSx/Ti-Fe2O3 with a thin MoSx layer on the surface of Ti-Fe2O3 fabricated a p–n junction that provided facile charge transfer pathways due to an internal electric field between Ti-Fe2O3 and MoSx, and achieved suppressed charge recombination. The optimized MoSx/Ti-Fe2O3 sample showed a 240% increased photocurrent density (3.03 mA cm−2) over pristine Fe2O3 at RHE 1.50 V. All our data including IPCE, PL, and EIS clearly confirmed the improved PEC performance of MoSx/Ti-Fe2O3 achieved by the formation of a p–n junction with a facile electron–hole transport pathway.

Patterned FTO was fabricated via a facile method as an efficient current collector in a photoelectrochemical water splitting system. The photocurrent density of α-Fe2O3 on patterned FTO exhibited a 1.7 times increase relative to α-Fe2O3 on FTO due to the light scattering and rapid transfer of excited electrons.

Objectives The purpose of this study was to evaluate the effect of bioactive glass (BAG)-containing composite on dentin remineralization. Methods Sixty-six dentin disks with 3 mm thickness were prepared from thirty-three bovine incisors. The following six experimental groups were prepared according to type of composite (control and experimental) and storage solutions (simulated body fluid [SBF] and phosphate-buffered saline [PBS]): 1 (undemineralized); 2 (demineralized); 3 (demineralized with control composite in SBF); 4 (demineralized with control composite in PBS); 5 (demineralized with experimental composite in SBF); and 6 (demineralized with experimental composite in PBS). BAG65S (65% Si, 31% Ca, and 4% P) was prepared via the sol-gel method. The control composite was made with a 50:50 Bis-GMA:TEGDMA resin matrix, 57 wt% strontium glass, and 15 wt% aerosol silica. The experimental composite had the same resin and filler, but with 15 wt% BAG65S replacing the aerosol silica. For groups 3–6, composite disks (20 × 10 × 2 mm) were prepared and approximated to the dentin disks and stored in PBS or SBF for 2 weeks. Micro-hardness test, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and field-emission scanning electron microscopy (FE-SEM) was investigated. Results The BAG-containing composite significantly increased the micro-hardness of the adjacent demineralized dentin. ATR-FTIR revealed calcium phosphate peaks on the surface of the groups which used BAG-containing composite. FE-SEM revealed surface deposits partially occluding the dentin surface. No significant difference was found between SBF and PBS storage. Clinical Significance Bioactive glass is a potentially useful material for remineralization of tooth structure. When incorporated into a resin composite, it may aid in remineralizing the adjacent demineralized dentin, thus preventing further destruction of the tooth. Conclusion BAG-containing composites placed in close proximity can partially remineralize adjacent demineralized dentin.

An ultrathin nickel hydroxide layer electrodeposited on a carbon-coated three-dimensional porous copper structure (3D-C/Cu) is suggested as an additive and binder-free conductive electrode with short electron path distances, large electrochemical active sites, and improved structural stability, for high performance supercapacitors. The 3D-porous copper structure (3D-Cu) provides high electrical conductivity and facilitates electron transport between the Ni(OH)2 active materials and the current collector of the Ni-plate. A carbon coating was applied to the 3D-Cu to prevent the oxidation of Cu, without degrading the electron transport behavior of the 3D-Cu. The 3D-Ni(OH)2/C/Cu exhibited a high specific capacitance of 1860 F g−1 at 1 A g−1, and good cycling performance, with an 86.5% capacitance retention after 10 000 cycles. When tested in a two-electrode system, an asymmetric supercapacitor exhibited an energy density of 147.9 W h kg−1 and a power density of 37.0 kW kg−1. These results open a new area of ultrahigh-performance supercapacitors, supported by 3D-Cu electrodes.

We have discovered a carbonized polymer film to be a reliable and durable carbon-based substrate for carbon enhanced Raman scattering (CERS). Commercially available SU8 was spin coated and carbonized (c-SU8) to yield a film optimized to have a favorable Fermi level position for efficient charge transfer, which results in a significant Raman scattering enhancement under mild measurement conditions. A highly sensitive CERS (detection limit of 10–8 M) that was uniform over a large area was achieved on a patterned c-SU8 film and the Raman signal intensity has remained constant for 2 years. This approach works not only for the CMOS-compatible c-SU8 film but for any carbonized film with the correct composition and Fermi level, as demonstrated with carbonized-PVA (poly(vinyl alcohol)) and carbonized-PVP (polyvinylpyrollidone) films. Our study certainly expands the rather narrow range of Raman-active material platforms to include robust carbon-based films readily obtained from polymer precursors. As it uses broad...

By coupling α-Fe2O3 with a 3D graphene inverse opal (3D-GIO) conducting electrode, the short diffusion length of carriers and low absorption coefficient in α-Fe2O3 for photoelectrochemical applications were successfully addressed. GIO was directly grown on FTO substrate under low temperature conditions, removing the need for a graphene transfer process. α-Fe2O3 nanoparticles (NPs) were hydrothermally deposited on the surface of GIO, creating α-Fe2O3/GIO. The photocurrent density of α-Fe2O3/GIO in water splitting reactions reached 1.62 mA/cm(2) at 1.5 V vs RHE, which is 1.4 times greater than that of optimized α-Fe2O3. The EIS and IPCE data confirm reduced electron-hole recombination and fast electron transfer processes due to the short distance between active materials and the conducting electrode in the α-Fe2O3/GIO system. Our result may pave the way for designing devices in advanced energy conversion applications as well as a high efficiency hematite-based PEC system.

We introduce a straightforward strategy to simultaneously improve the capacitance, rate capability, and cycle life of a supercapacitor by simply electrodepositing Ni-nanoparticles (Ni-NPs) on an as-prepared electrode. 3D-structured current collectors such as metal foams, metal meshes, and carbon meshes have been widely used in supercapacitors, secondary batteries, glucose sensors, etc. In particular, the 3D-metal foam readily improves device properties due to its unique 3D-nature and high surface area. However, there are practical constraints when applying 3D-current collectors to the industrial world, including high cost. Here, by simply electrodepositing Ni-NPs in a cost-efficient manner, a similar effect to that derived with the use of 3D-metal foam was realized. After deposition, Ni-NPs are preferentially located near the contact area between the active materials and a plate-type current collector, which allows for tight binding between the active materials and the current collector as well as facile charge transfer and high capacitance. The Ni-deposited Ni(OH)2 electrode pasted on a plate metal substrate showed 350% increased capacitance (1264 F g−1) and stability of 75% and 72% after 10 000 cycles and at a high current density of 20 A g−1, respectively. Given the simplicity and cost-efficiency of this method, it can be readily applied to other energy storage devices with practical applications in the industrial world.

We report great enhancement in photoelectrochemical water splitting efficiency of hematite assisted by fast and easy transfer of electrons/holes via a 3D-nanoporous gold (3D-NG) electrode. 3D-nanostructured α-Fe2O3/NG electrodes were fabricated in three subsequent procedures, de-alloying Au/Ag to produce a conductive 3D-NG electrode, decorating nanocrystalline β-FeOOH onto the nanopores of 3D-NG via a hydrothermal method, and converting β-FeOOH into α-Fe2O3. α-Fe2O3/3D-NG exhibits a maximum photocurrent density of 1.6 mA cm−2 at 1.5 V vs. RHE under AM 1.5 G simulated sunlight illumination via a photocatalytic hydrogen generation reaction, which is 2 times greater than that of the unmodified α-Fe2O3 photoanode. Incident photon-to-electron conversion efficiency (IPCE) and electrochemical impedance spectroscopy (EIS) data confirm that α-Fe2O3/3D-NG suppresses electron–hole recombination. The excellent performance of nanostructured hematites on 3D-nanoporous metal electrodes makes them promising candidates as electrodes with maximum efficiency in water splitting.

We report CVD-grown p-doped three-dimensional graphene nano-networks (3D-GNs) that provide superior performance to Pt as a counter electrode material in dye sensitized solar cells (DSSCs). The 3D-GN based DSSC exhibits a maximum photoconversion efficiency of 8.46%, which is 6.01% greater than that exhibited by Pt based DSSCs.

In this report, we show that by creating a nanoporous haematite (α-Fe2O3) structure using boric acid (H3BO3) treatment, the chronic issue of the short diffusion length of carriers in α-Fe2O3 for photoelectrochemical (PEC) applications can be successfully addressed. The slow release of Fe3+ ions because of the presence of H3BO3 leads to the creation of smaller dimension FeOOH nanorods, creating nanoporous α-Fe2O3 nanorods, composed of ∼15 nm α-Fe2O3 domains. The nanoporous α-Fe2O3 suppresses recombination by providing the facile extraction of holes from the surface of favorably sized α-Fe2O3 domains. The optimized nanoporous sample showed a photocurrent density of 1.41 mA cm−2 at a reversible hydrogen electrode of 1.23 V, which is 1.7 times higher than that of pristine hematite. The electrochemical impedance spectroscopy and incident photon-to-current efficiency data, and Mott–Schottky plots confirmed the superior performance of the nanoporous samples. Our impressive results may pave the way for designing devices for advanced energy conversion applications as well as fabricating a high efficiency hematite-based PEC system.

The evaporation sites of a solar desalination device were expanded from conventional 2D to a new type of 3D by leaving the side area of the porous water transporter exposed to the air. The 3D solar desalination device permits not only photothermal distillation by the photoabsorbers at the top under sunlight illumination, but also additional non-photothermal evaporation on the side of the water transporter that works even at night by exploiting environmental heat. For the first time, we developed a unique configuration of water transport exposed to the environment with a great contribution to an active site increase and confirmed the significant impact of the active site increase on the solar desalination performance by systematic and strong pieces of evidence. Due to the effective utilization of enormous evaporation sites on the top and side surfaces in the 3D configuration, the device exhibited a significant steam generation rate of ~0.74 g/h under 1 sun illumination, which is ~1.5 times higher than the maximum value achieved with photothermal evaporation only. Our study suggests an innovative change which incorporates additional non-photothermal evaporation in the solar desalination device can be a straightforward and efficient way to address clean water deficiencies worldwide in the future.

Introduction Cryopreservation preserves periodontal ligament cells but has a lower success rate with dental pulp cells (DPCs) because it causes inflammation. There are 2 well-known cryopreservation methods that reduce inflammation, slow freezing and rapid freezing, but the effects of the 2 methods on inflammation are not well-established. The purpose of this study was to compare the effects of the 2 different cryopreservation methods on CCL-13 induction from DPCs by using microarrays, real-time polymerase chain reaction (PCR), Western blotting, enzyme-linked immunosorbent assay, and confocal laser scanning microscopy (CLSM). Methods In this study, the concentration of cryoprotectant was fixed, and the methods compared differed with respect to freezing speed. Initially we screened the DPCs of cryopreserved teeth with expression microarrays, and CCL-13 was identified as a differentially expressed gene involved in generalized inflammation. We then compared the expression of CCL-13 after exposing teeth to the 2 cryopreservation methods by using real-time PCR, Western blot, enzyme-linked immunosorbent assay, and CLSM. Results Expression of CCL-13 was up-regulated significantly only in the rapid freezing group, except in measurements made by real-time PCR. CLSM analysis also confirmed this up-regulation visually. Conclusions Rapid freezing increased the expression of CCL-13 in DPCs compared with slow freezing. Understanding the inflammatory effect of cryopreservation should help to establish an optimal cryoprofile to minimize inflammation of DPCs and reduce the need for endodontic treatment.