Optical assistance in thin film microelectro-removal for touch-panel displays

Achieving a low yield of In₂O₃SnO₂ thin film nanostructures during the production of optoelectronic semiconductors is easy. A newly designed optical assistance module uses excimer irradiation in the deep ultraviolet to assist in the micro electro-removal process in a nano-scale recovery process for flexible display panels. The method effectively removes defective In₂O₃SnO₂ nanostructures from the surface of the optical PET-film (PET) of e-paper and allows the substrate to be returned to the production line. This study uses 172-nm excimer light to promote the efficient removal of In₂O₃SnO₂ nanostructures by the etching process. The excimer irradiation enhances the removal of the In₂O₃SnO₂ thin film which is easily broken into nano-particles and removed from the PET substrate quickly and cleanly. The time required for the etching process using excimer irradiation is shorter when compared to the time taken without irradiation under similar processing conditions. It was also shown that excimer irradiation is absolutely necessary to promote the etching effect with the designed tool to efficiently strip away the In₂O₃SnO₂ nanostructures.     

Pt nanoparticles-assisted electroless deposition of Prussian blue on the electrode: Detection of H2O2 with tunable sensitivity

In this communication, electroless deposition of Prussian blue (PB) on the electrode promoted by Pt nanoparticles (Pt_nano) is proposed for detecting H₂O₂ with adjustable sensitivity. Pt_nano/carbon nanotubes hybrid was initially used to modify the working electrode, followed by immersing it into the Fe³⁺[Fe^III(CN)₆] aqueous solution for electroless deposition of PB through a simple chemical reaction, which was catalyzed by Pt_nano. The amount of PB deposit was controllable through varying the deposition time or the Pt_nano amount on carbon nanotubes. Detection of H₂O₂ was successfully realized, sensitivity being dependent upon the amount of PB in the system. This work first demonstrates the feasibility of controlling the sensitivity of PB-based amperometric sensors through nanoparticles-assisted chemical deposition of PB, offering new insight into the development of electrochemical sensors using PB as the transducer.     

EQCM study of electrochemical modification of Bi2S3 films in the Zn-containing electrolyte

The electrochemical behavior of Bi₂S₃ as-deposited on Au using the successive ionic layer adsorption and reaction method has been investigated in the Zn²⁺-free background and Zn²⁺-containing electrolytes at different pH by electrochemical quartz crystal microbalance coupled with cyclic voltammetry and X-ray photoelectron spectroscopy. It has been shown that when the Bi₂S₃ film is reduced in the Zn²⁺-containing electrolyte Zn²⁺ ions are involved in electrochemical bismuth sulfide reduction and are partially reduced together with the bismuth sulfide film. The bismuth sulfide film initiates the adsorbed Zn²⁺ ions reduction prior to the traditional overpotential deposition of it. Reduction of Zn²⁺ ions prior to the overpotential deposition of Zn depends on solution pH: at pH 5 it occurs at more negative potential values and the observed mass changes due to Zn electrodeposition are greater than at solution pH 3. After bismuth sulfide film reduction in the Zn²⁺-containing electrolyte, Zn was detected as ZnO and metallic Zn at pH 5, while at pH 3 only ZnO was detected.     

The effect of doping Mg on the structure and electrochemical properties of Li3V2(PO4)3 cathode materials for lithium-ion batteries

The Mg-doped Li₃V_2−xMg_x(PO₄)₃ (x = 0.00, 0.01, 0.02, 0.05, 0.10, 0.20, 0.30, 0.33, 0.50, 1.00 and 1.33) compounds have been prepared by a sol–gel method in reducing atmosphere (70%Ar + 30%H₂) using citric acid as a chelating agent and a carbon source coated on the samples. The Mg-doped effects on the structural and electrochemical performance of Li₃V₂(PO₄)₃ are investigated by X-ray diffraction, galvanostatic, charge/discharge and four-point probe measurement method. The Li₃V_2−xMg_x(PO₄)₃ solid solution phase can exist stable in the composition range between x = 0.00 and 0.27. The simple improve mechanism of the electrochemical performance for Mg-doped Li₃V_2−xMg_x(PO₄)₃ system is discussed too. In the Mg-doped Li₃V_2−xMg_x(PO₄)₃ system, at a lower charge/discharge rate (0.1C), the cycle performance has no much improvement with the increasing Mg doping content. However, at higher rates, there has an excited improvement in both cycle performance and rate capability due to the increase of electrical conductivity (more than one order of magnitude). At 5C charge/discharge rate, for the Li₃V_1.95Mg_0.05(PO₄)₃ sample, the discharge capacities for the 1st and 100th cycle were 138.9 and 123.3 mAh g⁻¹. The discharge capacity retention reached to 89% (more than 51% for undoped Li₃V₂(PO₄)₃ system). More important is that, except for the first 15 cycles, the discharge capacities kept almost a constant. Based on the excellent electrochemical performance, Li₃V_1.95Mg_0.05(PO₄)₃ will be a promising cathode material for rechargeable lithium-ion batteries.     

Publisher’s note

Due to their physicochemical properties, Tm₂O₃ nanoparticles have been employed in bioanalytical applications. In this report, body-centered shaped Tm₂O₃ nanoparticles with size of about 10 nm were successfully synthesized by the hydrothermal homogeneous method and used as a novel electrochemical biosensing platform for glucose based on a Tm₂O₃–Nafion modified electrode. Transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS) were used to characterize the Tm₂O₃ nanoparticles, and cyclic voltammetry (CV) was used to investigate the electrochemical behavior of the modified electrode. The experimental results showed that glucose oxidase (GOD) immobilized on the Nafion–Tm₂O₃ film achieved direct electron transfer with an apparent heterogeneous electron transfer rate constant (k_s) of 3.27 ± 0.43 s⁻¹ and kept its bioactivity. Confirmation of the retained bioactivity can be demonstrated by its bioelectrocatalytic activity to the reduction of dissolved oxygen. The GOD/Tm₂O₃/Nafion/GC electrode displayed potential application for the fabrication of glucose biosensors with a linear glucose response up to 7 mM. Additionally, the biosensor based on the Tm₂O₃ nanoparticle-modified electrode exhibited good stability and selectivity. The successful practice of using the Tm₂O₃ modified electrode for the direct electrochemical analysis of proteins and the bioelectrocatalytic activity of enzymes offers an efficient strategy and a new promising platform for the application of rare earth oxide materials in the field of electrochemical sensors.     

牙科修复用BiOIO3/g-C3N4复合纳米光催化剂的制备与表征

目的 研究不同剂量NaOH条件对制备BiOIO3/g-C3N4复合纳米光催化剂的结构形貌及其可吸收光谱的影响,为研制适用于口腔修复纳米光催化功能性材料提供依据.方法 水热法制备BiOIO3/g-C3N4,通过XRD(X射线衍射仪)、SEM(扫描电镜图)和UV-vis(紫外-可见光吸收光谱)对其形貌、结构、分子组成和理化...     

Spectroelectrochemical investigation of MnO2 electro-generation and electro-reduction in acidic media

Spectroscopic investigations of Mn²⁺ electro-oxidation and MnO₂ electro-reduction in acidic media (0.5–2 M H₂SO₄) have been performed using optically transparent electrodes (OTE). Reticulated vitreous carbon (RVC) has been used as the electrode material. Our results show that in the first step of Mn²⁺ ions electro-oxidation the unstable in aqueous media Mn³⁺ ions are formed. In the next step Mn³⁺ ions can hydrolyse to MnOOH and/or disproportionate to Mn²⁺ and Mn⁴⁺ ions. Contrary to the electro-oxidation of Mn²⁺ to MnO₂, the electro-reduction of MnO₂ proceeds in two steps. The first step is strictly connected with electro-generation of MnOOH and the next with regeneration of Mn²⁺ ions.     

Electrocatalytic oxidation and reduction of H2O2 on vertically aligned Co3O4 nanowalls electrode: Toward H2O2 detection

Single crystal and vertically aligned cobalt oxide (Co₃O₄) nanowalls were synthesized by directly heating Co foil on a hot-plate under ambient conditions. The vertically aligned Co₃O₄ nanowalls grown on the plate show excellent mechanical property and were facilely attached to the surface of a glassy carbon (GC) electrode using conductive silver paint. The prepared Co₃O₄ nanowalls electrode was then applied to study the electrocatalytic oxidation and reduction of hydrogen peroxide (H₂O₂) in 0.01 M pH 7.4 phosphate buffer medium. Upon the addition of H₂O₂, the Co₃O₄ nanowalls electrode exhibits significant oxidation and reduction of H₂O₂ starting around +0.25 V (vs. Ag/AgCl), while no obvious redox activity is observed at a bare GC electrode over most of the potential range. The superior electrocatalytic response to H₂O₂ is mainly attributed to the large surface area, minimized diffusion resistance, high surface energy, and enhanced electron transfer of the as-synthesized Co₃O₄ nanowalls. The same Co₃O₄ nanowalls electrode was also applied for the amperometric detection of H₂O₂ and showed a fast response and high sensitivity at applied potentials of +0.8 V and −0.2 V (vs. Ag/AgCl), respectively. The results also demonstrate that Co₃O₄ nanowalls have great potential in sensor and biosensor applications.     

Biaxial flexural strength and phase transformation of Ce-TZP/Al2O3 and Y-TZP core materials after thermocycling and mechanical loading

PURPOSE

The purpose of the present study was to evaluate the effect of thermocycling and mechanical loading on the biaxial flexural strength and the phase transformation of one Ce-TZP/Al₂O₃ and two Y-TZP core materials.

MATERIALS AND METHODS

Thirty disc-shaped specimens were obtained from each material. The specimens were randomly divided into three groups (control, thermocycled, and mechanically loaded). Thermocycling was subjected in distilled water for 10000 cycles. Mechanical loading was subjected with 200 N loads at a frequency of 2 Hz for 100000 times. The mean biaxial flexural strength and phase transformation of the specimens were tested. The Weibull modulus, characteristic strength, 10%, 5% and 1% probabilities of failure were calculated using the biaxial flexural strength data.

RESULTS

The characteristic strengths of Ce-TZP/Al₂O₃ specimens were significantly higher in all groups compared with the other tested materials (P<.001). Statistical results of X-ray diffraction showed that thermocycling and mechanical loading did not affect the monoclinic phase content of the materials. According to Raman spectroscopy results, at the same point and the same material, mechanical loading significantly affected the phase fraction of all materials (P<.05).

CONCLUSION

It was concluded that thermocycling and mechanical loading did not show negative effect on the mean biaxial strength of the tested materials.     

Anti-M(3) muscarinic cholinergic autoantibodies from patients with primary Sjögren's syndrome trigger production of matrix metalloproteinase-3 (MMP-3) and prostaglandin E(2) (PGE(2)) from the submandibular glands

Background

We demonstrated that serum immunoglobulin G (IgG) from patients with primary Sjögren's syndrome (pSS), interacting with the second extracellular loop of human glandular M₃ muscarinic acetylcholine receptors (M₃ mAChR), trigger the production of matrix metalloproteinase-3 (MMP-3) and prostaglandin E₂ (PGE₂).

Methods

Enzyme-linked immunosorbent assays (ELISAs) were performed in the presence of M₃ mAChR synthetic peptide as antigen to detect in serum the autoantibodies. Further, MMP-3 and PGE₂ production were determined in the presence of anti-M₃ mAChR autoantibodies.

Results

An association was observed between serum and anti-M₃ mAChR autoantibodies and serum levels of MMP-3 and PGE₂ in pSS patients. Thus, we established that serum anti-M₃ mAChR autoantibodies, MMP-3 and PGE₂ may be considered to be early markers of pSS associated with inflammation. Affinity-purified anti-M₃ mAChR peptide IgG from pSS patients, whilst stimulating salivary-gland M₃ mAChR, causes an increase in the level of MMP-3 and PGE₂ as a result of the activation of phospholipase A₂ (PLA₂) and cyclooxygenase-2 (COX-2) (but not COX-1).

Conclusions

These results provide a novel insight into the role that cholinoceptor antibodies play in the development of glandular inflammation. This is the first report showing that an antibody interacting with glandular mAChR can induce the production of pro-inflammatory mediators (MMP-3/PGE₂).     

Bond strength of veneer ceramic and zirconia cores with different surface modifications after microwave sintering

PURPOSE

To evaluate the effects of surface treatments on shear bond strength (SBS) between microwave and conventionally sintered zirconia core/veneers.

MATERIALS AND METHODS

96 disc shaped Noritake Alliance zirconia specimens were fabricated using YenaDent CAM unit and were divided in 2 groups with respect to microwave or conventional methods (n=48/group). Surface roughness (Ra) evaluation was made with a profilometer on randomly selected microwave (n=10) and conventionally sintered (n=10) cores. Specimens were then assessed into 4 subgroups according to surface treatments applied (n=12/group). Groups for microwave (M) and conventionally (C) sintered core specimens were as follows; M_C,C_C: untreated (control group), M₁,C₁:Al₂O₃ sandblasting, M₂,C₂:liner, M₃,C₃:Al₂O₃ sandblasting followed by liner. Veneer ceramic was fired on zirconia cores and specimens were thermocycled (6000 cycles between 5°-55℃). All specimens were subjected to SBS test using a universal testing machine at 0.5 mm/min, failure were evaluated under an optical microscope. Data were statistically analyzed using Shapiro Wilk, Levene, Post-hoc Tukey HSD and Student''s t tests, Two-Way-Variance-Analysis and One-Way-Variance-Analysis (α=.05).

RESULTS

Conventionally sintered specimens (1.06 ± 0.32 µm) showed rougher surfaces compared to microwave sintered ones (0.76 ± 0.32 µm)(P=.046), however, no correlation was found between SBS and surface roughness (r=-0.109, P=.658). The statistical comparison of the shear bond strengths of C₃ and C₁ group (P=.015); C_C and M_C group (P=.004) and C₃ and M₃ group presented statistically higher (P=.005) values. While adhesive failure was not seen in any of the groups, cohesive and combined patterns were seen in all groups.

CONCLUSION

Based on the results of this in-vitro study, Al₂O_3- sandblasting followed by liner application on conventionally sintered zirconia cores may be preferred to enhance bond strength.     

不同浓度的过氧化氢对银汞合金表面性能的影响

目的研究不同浓度过氧化氢对银汞合金表面性能的影响。方法采用表面轮廓仪和扫描电镜对0 wt%、3.6 wt%、10 wt%和30 wt%四种浓度过氧化氢浸泡112 h后的牙科银汞合金的表面粗糙度、表面形貌进行比较,并运用光电子能谱仪分析0%和30%两种浓度过氧化氢浸泡后银汞合金的表面腐蚀产物。结果过氧化氢浸泡112 h后,不同银汞合金表面粗糙度的Ra和Rz的大小顺序均为0 wt%<3.6 wt%<10 wt%<30 wt%;且表面均有不同程度的腐蚀,主要表现为分布不均匀、孔径大小不一的点蚀,其中以30wt%过氧化氢浸泡组的腐蚀最明显;此外,0 wt%和30 wt%过氧化氢浸泡后,银汞合金表面分别检测到Cu、Sn、Hg、Ag、O元素,表面氧化物主要为SnO₂,与0 wt%过氧化氢相比,30 wt%过氧化氢浸泡后,银汞合金表面Ag、Hg、O元素含量明显下降,而Sn、Cu元素含量则升高。结论随着过氧化氢浓度的升高,银汞合金表面粗糙度增加,表面形貌有不同程度腐蚀,表面腐蚀产物成分有所改变,氧化程度减弱。     

Real surface area measurements of Pt3Co/C catalysts

An error analysis for real surface area (A_m) measurements of Pt₃Co/C catalysts is presented. The real surface area was measured by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), desorption of underpotential deposited hydrogen (H_upd) and CO-stripping voltammetry. All measurements were carried out after an electrochemical activation by cyclic voltammetry in perchloric acid. The real surface area decreases in the sequence A_m(XRD) ∼ A_m(HRTEM) > A_m(CO-stripping) ∼ A_m(H_upd). HRTEM provides the highest reliability of the investigated methods. The electrochemical methods are questionable for Pt₃Co/C catalysts. They yield surface areas which are 23–30% lower than determined by HRTEM. The surface coverage of adsorbed H and CO is apparently lower on Pt₃Co compared to Pt nanoparticles. Cyclic voltammetry of Pt₃Co/C in alkaline electrolyte suggests that the surface of acid leached Pt₃Co nanoparticles consists of pure Pt.     

Synthesis and electrochemical characterizations of nano size Ce doped LiMn2O4 cathode materials for rechargeable lithium batteries

LiCe_xMn_2−xO₄ (x = 0.00–0.10) cathode materials for rechargeable lithium-ion batteries were synthesized by simple sol–gel technique using aqueous solutions of metal nitrates and succinic acid as the chelating agent. The gel precursors of metal succinates were dried in vacuum oven for 10 h at 120 °C. After drying, the gel precursors were ground and heated at 900 °C. The structural characterization was carried out by X-ray powder diffraction and X-ray photoelectron spectroscopy to identify the valence state of Mn and Ce in the synthesized materials. The sample exhibited a well defined spinel structure and the lattice parameter linearly increased with increasing the cerium contents in LiCe_xMn_2−xO₄. Surface morphology and particle size of the synthesized materials were determined by scanning electron microscopy and transmittance electron microscopy respectively. Electrochemical properties were characterized for assembled Li/LiCe_xMn_2−xO₄ coin type cells using galvanostatic charge/discharge studies at 0.5C rate and cyclic voltammetry in the potential range between 2.75 and 4.5 V at a scan rate of 0.1 mV s⁻¹. Among them cerium doped spinel LiCe_0.05Mn_1.90O₄ has improved structural stability, high reversible capacity and excellent electrochemical performance of rechargeable lithium batteries.     

IL-17A stimulates the expression of inflammatory cytokines via celecoxib-blocked prostaglandin in MC3T3-E1 cells

Objective

The prostaglandins (PGs) released from osteoblasts can alter the process of bone remodelling. Recently, we showed that compressive force induced the expression of pro-inflammatory cytokine interleukin (IL)-17s and their receptors in osteoblastic MC3T3-E1 cells and that IL-17A was expressed most highly. Consequently, in the current study we examined the effect of IL-17A and/or celecoxib on PGE₂ production and the expression of cyclooxygenases (COXs) and inflammatory cytokines in MC3T3-E1 cells. We also examined the effects of PGE₂ and cyclohexamide on the expression of inflammatory cytokines.

Methods

Cells were cultured with or without IL-17A (0.1, 1.0, or 10 ng/ml) in the presence or absence of 10 μM celecoxib, a specific inhibitor of COX-2, for up to 72 h. Cells were pretreated with or without 10 μg/ml cycloheximide, protein synthesis inhibitor, for 30 min, and then cultured with 10 ng/ml IL-17A for 24 h. Cells were also cultured with or without 1.5 ng/ml PGE₂ for 24 h. PGE₂ production was determined by ELISA. The expression of COX-1, COX-2, IL-1α, IL-6, IL-8, IL-11, and TNF-α mRNAs and proteins was determined by real-time PCR and ELISA, respectively.

Results

The expression of COX-2, IL-1α, IL-6, IL-8, IL-11, and TNF-α, as well as PGE₂ production increased in the presence of IL-17A, whereas COX-1 expression did not change. Celecoxib blocked the stimulatory effect of IL-17A on the expression of COX-2, IL-1α, IL-6, IL-8, and IL-11 as well as PGE₂ production, whereas it did not block TNF-α expression. Cycloheximide pretreatment suppressed the expression of IL-17-induced inflammatory cytokines. The expression of IL-1α, IL-6, IL-8, and IL-11 increased by the addition of PGE₂, whereas TNF-α expression was not affected.

Conclusion

These results suggest that IL-17A stimulates the expression of bone resorption-related inflammatory cytokines through an autocrine mechanism involving celecoxib-blocked PGs, mainly PGE₂, in osteoblasts.     

Biomechanical properties of nano-TiO2 addition to a medical silicone elastomer: The effect of artificial ageing

Objectives

The aim of this study was to evaluate the effect of TiO₂ nanoparticles on the mechanical and anti-ageing properties of a medical silicone elastomer and to assess the biocompatibility of this novel combination.

Methods

TiO₂ (P25, Degussa, Germany) nanoparticles were mixed with the silicone elastomer (MDX4-4210, Dow Corning, USA) at 2%, 4%, and 6% (w/w) using silicone fluid as diluent (Q7-9180, Dow Corning, USA). Blank silicone elastomer served as the control material. The physical properties and biocompatibility of the composites were examined. The tensile strength was tested for 0% and 6% (w/w) before and after artificial ageing. SEM analysis was performed.

Results

TiO₂ nanoparticles improved the tensile strength and Shore A hardness of the silicone elastomer (P < 0.05). However, a decrease in the elongation at break and tear strength was found for the 6% (w/w) composite (P < 0.05). All the ageing methods had no effect on the tensile strength of the 6% (w/w) composite (P > 0.05), but thermal ageing significantly decreased the tensile strength of the control group (P < 0.05). Cellular viability assays indicated that the composite exhibited biocompatibility.

Conclusions

We obtained a promising restorative material which yields favourable physical and anti-ageing properties and is biocompatible in our in vitro cellular studies.     

Multi-photon microscopic imaging of rat parotid ducts demonstrates cellular heterogeneity in Ca2+ responsiveness

The heterogeneity of salivary ductal cells, with regard to their sensitivity to Ca(2+)-mobilizing agonists, was visualized by multi-photon microscopy. Stimulation of isolated parotid ducts with 0.1 and 1 microM epinephrine (Epi) elevated the intracellular Ca(2+) levels ([Ca(2+)](i)) in approximately 30% and >90% of the ductal cells, respectively. Of the 0.1 microM Epi-responsive cells, 80% responded rapidly to subsequent stimulation with 1 microM Epi. Similarly, threshold concentrations (0.5 or 1 microM) of phenylephrine (PhL), carbachol (CCh) or ATP, induced responses in approximately 20% of the ductal cells, and subsequent stimulations with 10 microM of the same agonist activated approximately 80% of ductal cells. These observations indicate that parotid ducts contain a certain subpopulation of cells, which exhibits particularly high sensitivity to these Ca(2+)-mobilizing agonists, compared to the remaining ductal cells. Sequential stimulation with threshold concentrations of PhL, CCh, and ATP induced Ca(2+) responses in approximately 33% of ductal cells. Of these responsive cells, the majority (69%) could only respond to one of the three agonists; while a small minority (9%) were capable of responding to all three agonists. These results indicate that low concentrations of PhL, CCh, and ATP activate different subpopulations of parotid ductal cells.     

Regulation of Ca signals in a parotid cell line Par-C5

The Ca²⁺ signaling system in an established immortalized rat parotid acinar cell line, Par-C5, was examined using the Ca²⁺-sensitive fluorescent indicator fura-2 and by measuring inositol 1,4,5-trisphosphate (IP₃) formation. Agonist-induced increase in intracellular Ca²⁺ ([Ca²⁺]_i) by mobilization of intracellular stores and influx across the cell membrane was stimulated by acetylcholine (ACh) and ATP, whereas noradrenaline-(NA)-induced a small [Ca²⁺]_i increase mediated primarily by release from intracellular Ca²⁺ stores. [Ca²⁺]_i increase by ACh and ATP was meditated through the phosphoinositide signal pathway since both agonists significantly increased 1,4,5-IP₃ formation and Ca²⁺ mobilization was abolished by the phospholipase C inhibitor U73122. In Ca²⁺-free medium, ACh or ATP discharged the IP₃-sensitive Ca²⁺ store and essentially abolished subsequent [Ca²⁺]_i response to thapsigargin (TG). Exposure to ionomycin and monensin after TG induced a further mobilization of Ca²⁺, suggesting IP₃-insensitive stores are present. Furthermore, depletion of IP₃-sensitive Ca²⁺ stores by TG, ACh and ATP enhanced plasmalemmal Ca²⁺-entry pathways. Exposure to tumor necrosis factor-α (TNF-α), a cytokine associated with lymphocyte invasion of salivary epithelial cells in autoimmune disorders, significantly reduced ACh-stimulated Ca²⁺ mobilization. TNF-α inhibitory effect on Ca²⁺ mobilization was not directly due to an interaction on muscarinic receptors since ACh-induced 1,4,5-IP₃ formation was not altered. These results in the Par-C5 cell line indicate 1) [Ca²⁺]_i is regulated by muscarinic and P2Y-nucleotide receptors and partly by α₁-adrenergic receptors; 2) IP₃-sensitive and -insensitive Ca²⁺ stores exist; 3) Ca²⁺ influx activated by ACh, ATP or TG is mediated by the store-operated Ca²⁺ entry pathway; and 4) muscarinic agonist-stimulated Ca²⁺ mobilization is altered by the cytokine TNF-α.