Lead-Free Piezoelectric Acceleration Sensor Built Using a (K,Na)NbO3 Bulk Ceramic Modified by Bi-Based Perovskites.

Piezoelectric accelerometers using a lead-free (K,Na)NbO3 (KNN) piezoceramic modified by a mixture of two Bi-based perovskites, Bi(Na,K,Li)ZrO3 (BNKLZ) and BiScO3 (BS), were designed, fabricated and characterized. Ring-shaped ceramics were prepared using a conventional solid-state reaction method for integration into a compression-mode accelerometer. A beneficial rhombohedral-tetragonal (R-T) phase boundary structure, especially enriched with T phase, was produced by modifying intrinsic phase transition temperatures, yielding a large piezoelectric charge coefficient d33 (310 pC/N) and a high Curie temperature Tc (331 °C). Using finite element analyses with metamodeling techniques, four optimum accelerometer designs were obtained with high magnitudes of charge sensitivity Sq and resonant frequency fr, as evidenced by two key performance indicators having a trade-off relation. Finally, accelerometer sensor prototypes based on the proposed designs were fabricated using the KNN-BNKLZ-BS ceramic rings, which exhibited high levels of Sq (55.1 to 223.8 pC/g) and mounted fr (14.1 to 28.4 kHz). Perfect charge-to-acceleration linearity as well as broad flat frequency ranges were achieved with excellent reliability. These outstanding sensing performances confirm the potential application of the modified-KNN ceramic in piezoelectric sensors.

Reactive Oxygen Species and Folate Receptor-Targeted Nanophotosensitizers Composed of Folic Acid-Conjugated and Poly(ethylene glycol)-Chlorin e6 Tetramer Having Diselenide Linkages for Targeted Photodynamic Treatment of Cancer Cells.

Folic acid-conjugated nanophotosensitizers composed of folic acid (FA), poly(ethylene glycol) (PEG) and chlorin e6 (Ce6) tetramer were synthesized using diselenide linkages for reactive oxygen species (ROS)- and folate receptor-specific delivery of photosensitizers. Ce6 was conjugated with 3-[3-(2-carboxyethoxy)-2,2-bis(2-carboxyethoxymethyl)propoxy]propanoic acid (tetra acid, or TA) to make Ce6 tetramer via selenocystamine linkages (TA-sese-Ce6 conjugates). In the carboxylic acid end group of the TA-sese-Ce6 conjugates, FA-PEG was attached again using selenocystamine linkages to make FA-PEG/TA-sese-Ce6 conjugates (abbreviated as FAPEGtaCe6 conjugates). Nanophotosensitizers were fabricated by a dialysis procedure. In the morphological observations, they showed spherical shapes with small diameters of less than 200 nm. Stability of the aqueous FAPEGtaCe6 nanophotosensitizer solution was maintained (i.e., their particle sizes were not significantly changed until 7 days later). When H2O2 was added to the nanophotosensitizer solution, the particle size distribution was changed from a monomodal pattern to a multimodal pattern. In addition, the fluorescence intensity and Ce6 release rate from the nanophotosensitizers were also increased by the addition of H2O2. These results indicated that the nanophotosensitizers had ROS-sensitive properties. In an in vitro cell culture study, an FAPEGtaCe6 nanophotosensitizer treatment against cancer cells increased the Ce6 uptake ratio, ROS generation and light-irradiated cytotoxicity (phototoxicity) compared with Ce6 alone against various cancer cells. When the folic acid was pretreated to block the folate receptors of the Y79 cells and KB cells (folate receptor-overexpressing cells), the intracellular Ce6 uptake, ROS generation and thereby phototoxicity were decreased, while the MCF-7 cells did not significantly respond to blocking of the folate receptors. These results indicated that they could be delivered by a folate receptor-mediated pathway. Furthermore, an in vivo pulmonary metastasis model using Y79 cells showed folate receptor-specific delivery of FAPEGtaCe6 nanophotosensitizers. When folic acid was pre-administered, the fluorescence intensity of the lungs was significantly decreased, indicating that the FAPEGtaCe6 nanophotosensitizers had folate receptor specificity in vitro and in vivo. We suggest that FAPEGtaCe6 nanophotosensitizers are promising candidates for a targeted photodynamic therapy (PDT) approach against cancer cells.

Enhanced Photocatalytic Performance of Nanosized Mixed-Ligand Metal-Organic Frameworks through Sequential Energy and Electron Transfer Process.

Effective sequestration of harmful organic pollutants from wastewater has been a persistent concern in the interest of environmental and ecological protection from pollution and hazards. Currently, common water treatment technologies such as adsorption, coagulation, and membranes are expensive and not greatly effective. A new class of organic and inorganic composite metal-organic frameworks (MOFs) has emerged as an essential class of materials for numerous applications, including photocatalytic degradation of organic pollutants. Herein, we present a nanosize mixed-ligand MOF (nMLM) which was successfully synthesized by reacting a Zr metal source with a mixture of pyrene and porphyrin building units and further utilized as photocatalyst in the photodegradation of rhodamine B (RhB). The nMLM MOF showed excellent photocatalytic efficiency, which was due to the complementary absorption and sequential energy and electron transfer properties of its building blocks, pyrene and porphyrin. We also propose herein a possible mechanism of the photocatalytic function of the material.

Charge transport in pyroprotein-based electronic yarns.

Pyroprotein-based carbon materials produced by heat-treating silk proteins have many potential applications in electronic devices, such as electronic textiles. To further develop potential electronic devices using these pyroproteins, the charge transport mechanism has to be verified. However, the electrical characteristics of the pyroproteins have not been reported yet. In this study, the temperature-dependent charge transport behavior of pyroprotein-based electronic yarns prepared from commercial silks (e-CS yarns) is investigated with respect to various heat treatment temperatures (HTT, 800, 1000, 1200, and 1400 °C). The linear current-voltage properties are shown at a low bias of 100 nA from 9 K to 300 K. The temperature-dependent resistivity of the e-CS yarns can be clearly described by the crossover of 3-dimensional Mott variable range hopping and fluctuation-induced tunneling conduction at the crossover temperature (Tc). These Tc factors are significantly different, due to the structural modulation of the e-CS yarns depending on the HTT, and are characterized by Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. This study is expected to provide a better understanding of the electrical properties of pyroproteins.

Reconstruction of Mandibular Defects With Bone Marrow-Derived Stem Cells in Odontogenic Myxoma.

Odontogenic myxoma is a benign tumor, mostly located in the mandible. It shows locally aggressive behavior and requires surgical removal. Common treatment options for reconstructing the bone defects are immediate or delayed autologous bone graft or free flap. In this article, the authors present the successful reconstruction with autogenous bone graft and autologous human bone marrow mesenchymal stem, followed by distraction osteogenesis, dental implant placement and prosthodontic restoration in the mandibular defect.

Combinatorial Effect of Cold Atmosphere Plasma (CAP) and the Anticancer Drug Cisplatin on Oral Squamous Cell Cancer Therapy.

Cold atmospheric plasma (CAP) has been extensively investigated in the local treatment of cancer due to its potential of reactive oxygen species (ROS) generation in biological systems. In this study, we examined the synergistic effect of combination of CAP and cisplatin-mediated chemotherapy of oral squamous cell carcinoma (OSCC) in vitro. SCC-15 OSCC cells and human gingival fibroblasts (HGF-1) cells were treated with cisplatin, and then, the cells were irradiated with CAP. Following this, viability and apoptosis behavior of the cells were investigated. The viability of SCC-15 cells was inhibited by cisplatin with a dose-dependent manner and CAP treatment time. HGF-1 cells also showed decreased viability by treatment with cisplatin and CAP. Combination of 1 µM cisplatin plus 3 min of CAP treatment or 3 µM cisplatin plus 1 min of CAP treatment showed a synergistic anticancer effect with appropriate cytotoxicity against normal cells. ROS generation and dead cell staining were also increased by the increase in CAP treatment time. Furthermore, tumor-suppressor proteins and apoptosis-related enzymes also increased according to the treatment time of CAP. We showed the synergistic effect of cisplatin and CAP treatment against SCC-15 cells with low cytotoxicity against normal cells.

Tuning the electronic structure of single-walled carbon nanotube by high-pressure H2 exposure.

We report on an electronic structure change of single-walled carbon nanotube (SWNT) on hexagonal boron nitride due to electron doping via high-pressure H2 exposure. The fractional coverage of hydrogenated carbon atom is estimated to be at least θ = 0.163 from the in situ I ds-V g measurements of the release process. Raman spectroscopy and x-ray photoelectron spectroscopy were carried out to support the in situ electrical measurements. In particular, we used the dissociative Langmuir-type model to yield the desorption coefficient k des by fitting it to the in situ electrical data. Finally, we applied this hydrogenation method to the SWNT network on the commercial Si/SiO2 substrate to open the possibility of the scalable n-type semiconducting SWNT FETs.

Decyl Glucoside Synthesized by Direct Glucosidation of D-Glucose Over Zeolite Catalysts and Its Estrogenicity as Non-Endocrine Disruptive Surfactant.

The estrogenicity of decyl glucoside was asserted as a non-endocrine disruptive surfactant with its preparation method using zeolite catalysts. Its estrogenicity was estimated using E-assay method. The decyl glucoside was synthesized by direct glucosidation from D-glucose with 1-decanol. The conversion and yield were improved with increasing of amount of acid sites of the zeolite catalysts. The decyl glucopyranoside is more hydrophilic than nonylphenol and has a high wettability. The decyl glucopyranosides exhibited extremely lower proliferation of estrogenic cell compared with nonylphenol.

Electronic-dimensionality reduction of bulk MoS2 by hydrogen treatment.

A reduction in the electronic-dimensionality of materials is one method for achieving improvements in material properties. Here, a reduction in electronic-dimensionality is demonstrated using a simple hydrogen treatment technique. Quantum well states from hydrogen-treated bulk 2H-MoS2 are observed using angle resolved photoemission spectroscopy (ARPES). The electronic states are confined within a few MoS2 layers after the hydrogen treatment. A significant reduction in the band-gap can also be achieved after the hydrogen treatment, and both phenomena can be explained by the formation of sulfur vacancies generated by the chemical reaction between sulfur and hydrogen.

Oxygen and Acrylic Acid Plasma Treatment on Titanium Mesh for Improving the Hydroxyapatite Formation.

Customized titanium (Ti) meshes were treated with O2 plasma and acrylic acid plasmapolymerization (PPAAc). The optimum conditions for PPAAc were as follows: 20 W, 15 mTorr, and 5 min. Hydroxyapatite formation increased in Ti meshes treated with O2 and PPAAc compared with that in untreated Ti meshes. Moreover, MC3T3-E1 cells exhibited improved cell spreading, attachment, proliferation in PPAAc treated Ti mesh than in untreated Ti mesh. This result revealed that O2 and PPAAc surface treatment on Ti mesh was potential tool for improving the bone formation on the Ti mesh clinically application.

Estrogenicity of Octyl Glucoside Synthesized by Direct Glucosidation as Non-Endocrine Disruptive Surfactant.

The estrogenicity of octyl glucoside was studied with its preparation method using microporous zeolites. Its estrogenicity was estimated using E-assay method to confirm the possibility as non-endocrine disruptive surfactant. The octyl glucoside was synthesized from D-glucose with 1-octanol by direct glucosidation. The high conversion of D-glucose was obtained on H-FAU zeolite which has a mild acid strength. The conversion and yield were improved with increasing of acid site amount of the zeolite catalysts. The octyl glucopyranoside is more hydrophilic than nonylphenol and has a high wettability. The octyl glucosides represented extremely lower estrogenic cell proliferation compared with nonylphenol.

Oxygen Plasma Treatment on 3D-Printed Chitosan/Gelatin/Hydroxyapatite Scaffolds for Bone Tissue Engineering.

The 3D hydroxyapatite/gelatin/chitosan composite scaffolds were fabricated by 3D printing technique. The scaffolds were treated by oxygen plasma to improve the bioactivity and its surface characterization and in vitro cell culture were investigated. The scaffolds exhibited the good porosity and interconnectivity of pores. After oxygen plasma etching, roughness and wettability on the scaffolds surface are increased. Plasma treated scaffolds showed higher proliferation than that of untreated scaffolds. Oxygen plasma treatment could be used as potential tool to enhance the biocompatibility on the 3D composite scaffolds.

In Vitro Study on the Plasma-Polymerization of Propionaldehyde and Allylglycidyl Ether for Immobilization of Recombinant Human Bone Morphogenetic Protein-2.

In this study, recombinant human bone morphogenetic protein-2 (rhBMP-2) was directly immobilized on the plasma-polymerized propionaldehyde (PA) and allylglycidyl ether (AGE) surface through the imine bonding and epoxy-amine bonding, respectively. Aldehyde and epoxide plasma-polymerization were carried out at plasma power 60 W for 10 min and monomers were used to PA and AGE. After the plasma-polymerization and rhBMP-2 immobilization, substrate surfaces were characterized by contact angle, field emission scanning electron microscopy, and attenuated total reflectance Fourier transform infrared. In addition, the biological activities of MC3T3-E1 cells were evaluated by initial adhesion and alkaline phosphate (ALP) activity. The rhBMP-2 immobilized PA and AGE surfaces promoted significantly higher ALP activity of MC3T3-E1 cells than pristine surface.

Tin Oxide/Carbon Nanocomposites as the Electrode Material for Supercapacitors Using a Liquid Phase Plasma Method.

Tin oxide/carbon nanocomposite (TOCNC) was synthesized using a liquid phase plasma method, to be used as the electrode of supercapacitor. Spherical tin oxide amorphous nanoparticles with the size of 5 nm were dispersed uniformly on activated carbon powder (ACP) surface. The quantity of tin oxide nanoparticle precipitate increased with increasing LPP duration and the specific capacitance of TOCNC increased with increasing LPP duration. The TOCNC prepared through the LPP process showed smaller resistances and larger initial resistance slopes than bare ACP and this effect was intensified by increasing the LPP process duration.

Variation in the c-axis conductivity of multi-layer graphene due to H2 exposure.

The variation of the c-axis conductivity of a multilayer graphene (MLG) as a function of H2 pressure from vacuum to 20 bar has been investigated. MLG was connected to the electrodes vertically using a wet transfer process. After exposure to H2 gas pressure up to 20 bar, the chemisorption of dissociated atomic hydrogen on MLG affects its electrical and structural properties. The formation of C-H bonds causes a decoupling of graphene layers, and then interferes with charge transfer through the out of plane. As a result, the c-axis conductivity decreases. Furthermore, the electron doping effect and the decoupling of the layers were confirmed using Raman spectroscopy. Hydrogenated carbons induce a defect structure of MLG which results in the expansion of layers. We observed a 43.54% increase in the thickness of the MLG after H2 exposure using atomic force microscopy.

Cell Proliferation on Macro/Nano Surface Structure and Collagen Immobilization of 3D Polycaprolactone Scaffolds.

In this study, 3D polycaprolactone (PCL) scaffolds were fabricated by 3D printing technique. The macro/nano morphology of, 3D PCL scaffolds surface was etched with oxygen plasma. Acrylic acid (AA) plasma-polymerization was performed to functionalize the macro/nano surface with carboxyl groups and then collagen was immobilized with plasma-polymerized 3D PCL scaffolds. After O2 plasma and AA plasma-polymerization, contact angles were decreased. The FE-SEM and AFM results showed that O2 plasma is increased the surface roughness. The MTT assay results showed that proliferation of the M3CT3-E1 cells increased on the oxygen plasma treated and collagen immobilized 3D PCL scaffolds.

O2/Ar Plasma Treatment for Enhancing the Biocompatibility of Hydroxyapatite Nanopowder and Polycaprolactone Composite Film.

In this study we performed O2/Ar plasma treatment to remove the polycaprolactone on hydroxyapatite nanopowder and polycaprolactone (HAp-NP/PCL) composite film. After plasma ashing, the HAp-NP was exposed on the composite film. The 25 wt% HAp-NP/PCL treated with plasma showed the hydrophilic surface property with reducing the aging effect. The MTT and ALP results indicated that the plasma etching increased the biocompatibility of HAp-NP/PCL composite film. The present simple plasma etching technique can be applicable in a development of biomaterials.

Characteristics of Plasma Treated Electrospun Polycaprolactone (PCL) Nanofiber Scaffold for Bone Tissue Engineering.

Polycaprolactone (PCL) nanofibers (PCL-NF) with uniform fibrous structure were fabricated by electrospinning. However, PCL-NF has hydrophobic surface, lacks functional groups and hence it is not a good substrate for cell adhesion. To improve the cell adhesion, PCL-NF surfaces were modified by low pressure RF discharge plasma treatment using monomer such as acrylic acid or oxygen gas. The plasma treated PCL-NFs improved the wettability and cell proliferation.

Oxygen and Nitrogen Gas Plasma Surface Treatments on Titanium for Initial Adhesion and Proliferation of Preosteoblast Cells.

In this study, titanium (Ti) surface was treated through the use of oxygen and nitrogen plasma for improving the initial adhesion and proliferation of preosteoblast cells. The plasma treated Ti surface demonstrated hydrophilic surface property and promoted initial adhesion and proliferation of preosteoblast cells.

Fabrication of 3D Scaffolds with Nano-Hydroxyapatite for Improving the Preosteoblast Cell-Biological Performance.

Three-dimensional (3D) scaffolds fabricated by rapid prototyping techniques have many merits for tissue engineering applications, due to its controllable properties such as porosity, pore size and structural shape. Nonetheless, low cell seeding efficiency remains drawback. In this study, poly-caprolactone (PCL) composite 3D extruded scaffolds were modified with nano hydroxyapatite (n-HAp). PCL/n-HAp 3D scaffold surface was treated with oxygen plasma to improve the preosteoblast cell seeding efficiency and proliferation. The results indicate that oxygen plasma is useful technique to improve the cell affinity.