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Zwitterionic polymers have extraordinary properties, that is, significant hydration and the so-called antipolyelectrolyte effect, which make them suitable for biomedical applications. The hydration induces an antifouling effect, and this has been investigated significantly. The antipolyelectrolyte effect refers to the extraordinary ion-responsive behavior of particular polymers that swell and hydrate considerably in physiological solutions. This actuation begins to attract attention to achieve in vivo antifouling that is challenging for general polyelectrolytes. In this study, we established the sophisticated cornerstone of the antipolyelectrolyte effect in detail, including (i) the essential parameters, (ii) experimental verifications, and (iii) effect of improving antifouling performance. First, we find that both osmotic force and charge screening are essential factors. Second, we identify the antipolyelectrolyte effect by visualizing the swelling and hydration dynamics. Finally, we verify that the antifouling performance can be enhanced by exploiting the antipolyelectrolyte effect and report reduction of 85% and 80% in ex and in vivo biofilm formation, respectively.

Amorphous indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) have shown significant potential for application in transparent and flexible electronic devices. However, the source and drain (S/D) electrodes of IGZO TFTs with indium tin oxide (ITO) thin films can cause Schottky-like behavior in the output characteristics owing to the formation of a potential barrier between the IGZO and ITO thin films. In this study, we designed and fabricated TFTs by applying a novel ITO S/D electrode layer (375 nm) with co-sputtered IGZO and ITO thin films (125 nm) deposited at room temperature. The proposed TFT exhibits superior electric characteristics ( $\mu _{\text {sat}} =35.4$ cm2/Vs) compared to those of TFTs with conventional ITO electrodes ( $\mu _{\text {sat}} =9.1$ cm2/Vs) owing to its lower contact and channel resistance and the generation of a surface reaction between S/D and channel layers, creating additional oxygen vacancies at the IGZO channel region. The proposed S/D electrode could be fabricated on a glass substrate at low temperatures (below 200 °C). The excellent electrical properties of the proposed IGZO TFT are expected to promote the application of TFTs in advanced displays.

Technologies that can overcome the poor mechanical properties of the coatings with bacterial anti-adhesion effect based on super-wetting properties are still challenging. In this study, we developed a durable superhydrophilic nanocomposite coatings composed of polysaccharide matrix and organosilicate (OS) compound filler. In brief, carboxymethylcellulose (CMC) and chitosan (CS)-based multilayer films were fabricated via Layer-by-layer (LbL) assembly then crosslinking for the films was performed to improve inner stability and induce superhydrophilicity. As second step, we synthesized a biocompatible and robust organosilicate compound via sol-gel reaction and incorporate it as reinforcing filler into the superhydrophilic films. Consequently, durable hybrid superhydrophilic nanocomposites were coated on the substrate, and various chemical analysis and performance evaluations of the coatings were performed. The mechanical properties of the composite coatings were significantly improved due to the OS acting as a reinforcing filler in the multilayer films. Furthermore, the coatings exhibited excellent biocompatibility and transparency and exerted antibacterial effect based on superhydrophilic property. This study presents a practical strategy to solve the poor durability, the limitation of super-wetting coatings widely applied in various fields.

In the medical industry, zwitterionic brushes have received significant attention owing to their antifouling effect that arose from their hydration ability. However, sufficient understanding of the hydration dynamics of zwitterionic brushes is required to fabricate the precisely controlled antifouling medical devices. In this paper, we successfully show that hydration, the interaction between water molecules and zwitterionic brushes, and its dynamics can be evaluated logically and quantitatively using (i) water contact angle, (ii) molecular dynamics simulation, and (iii) Raman spectroscopy. Based on the intuitive results on hydration, we precisely optimized the antifouling property of the model medical device, a removable orthodontic retainer, with various grafting efficiencies of 2-methacryloyloxyethyl phosphate choline. As a result, the model device reduced nonspecific adsorption of proteins and bacteria, indicating an improved antifouling effect, and also inhibited the formation of a biofilm. Furthermore, the device showed excellent physical properties desirable for application in the orthodontic field, meaning the balance between the antibacterial property and mechanical strength.

This study evaluated the synergetic effect between surface pre-reacted glass-ionomer (SPRG) filler and 2-methacryloyloxyethyl phosphorylcholine (MPC), for inhibiting multi-species biofilm formation, while maintaining or even improving the original beneficial features of SPRG-filled resin-based composite (RBC).MPC (1.5-10wt%) was incorporated into commercial SPRG-filled RBC. Then, the inherent properties of RBC, and ion release and acid-neutralising properties associated with SPRG were investigated. Further, protein adsorptions and bacterial adhesion and viability on the SPRG-filled RBC surfaces were studied using four kinds of oral bacteria; Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, and Porphyromonas gingivalis. Finally, the thickness and biomass of the human saliva-derived biofilm model cultured on test and control samples were analysed.Addition of MPC content resulted in decreased flexural strength and wettability of SPRG-filled RBC. SPRG-filled RBC released significantly higher amounts of multiple ions as contents of MPC increased. Meanwhile, SPRG-filled RBC with 5-wt% MPC significantly improved acid-neutralising properties than those of other test and control samples (P0.001). SPRG-filled RBC with 3wt% MPC significantly reduced the amount of adsorbed bovine serum albumin and proteins from the brain heart infusion medium as compared to the control (P0.01). A similar trend was observed in the attachment of four types of bacteria and multi-species biofilm (P0.01).Despite limitation in terms of deteriorations of some physical properties, addition of 3% MPC to SPRG-filled RBC leads to inhibition of the attachment of multi-species bacteria on its surface, as well as inhibition of biofilm growth. Moreover, the original important bioactive features of SPRG-filled RBC such as ion release and acid neutralisations are either maintained or improved upon adding MPC.

The properties of underlying substrates influence the quality of an intraoral scan, but few studies have compared the outcomes using common restorative materials. In this study, we aimed to compare the accuracy of digital and conventional impressions recorded for four different dental materials as the substrates. Experimental crowns were produced with a metallic surface (gold or cobalt-chromium alloy (Co-Cr)) or without a metallic surface (zirconia or PMMA (polymethyl methacrylate)). A conventional impression was made in the conventional group (CON group), and gypsum models were subsequently scanned with a tabletop scanner. An intraoral scanner was used to scan the crowns either after applying a powder spray to reduce the surface reflectivity (IOS-P group) or without the powder spray (IOS group). The scans were assessed in three dimensions for precision and trueness. The accuracy did not differ between the CON and IOS groups for the non-metallic crowns. However, it was statistically different for the Co-Cr metallic crown, reducing trueness observed between groups as CON &gt, IOS &gt, IOS-P. The study evidences the differences in outer surface accuracy observed with a change in the substrate material to be imaged using an oral scanner and with the impression method. These findings suggest that the restoration material present in the oral cavity should be considered when selecting an impression-taking method.

This study aims to compare the torque values for various lengths of the titanium-based orthodontic anchor screw (OAS), different anchorage methods and varying artificial bone densities after predrilling. Furthermore, the effects of these parameters on bone stability are evaluated. A total of 144 OASs were prepared with a diameter of 1.6 mm and heights of 6, 8 and 10 mm. Artificial bones were selected according to their density, corresponding to Grades 50, 40 and 30. Torque values for the automatic device and manual anchorage methods exhibited a statistically significant difference for the same-sized OAS, according to the bone density of the artificial bones (p &lt, 0.05). However, when insertion torque was at the maximum rotations, there was no significant difference in the torque values for the Grade 30 artificial bone (p &gt, 0.05). When the torque values of both anchorage methods were statistically compared with the mean difference for each group, the results of the manual anchorage method were significantly higher than those of the automatic device anchorage method (p &lt, 0.05). A statistically significant difference was observed in the bone stability resulting from different OAS anchorage methods and artificial bone lengths. These findings suggest that the automatic anchorage method should be used when fixing the OAS.

It is essential for 3D-printed intra-oral appliances to be able to withstand the mechanical and microbial insult existent in the harsh environment of the oral cavity. Poly(methyl methacrylate) (PMMA)-based appliances are widely used in dentistry. Hence, the present study aimed to evaluate the role of nanodiamonds (NDs) as fillers to enhance the resistance to friction and wear. Using a solution-based mixing technique, 0.1 wt% ND was incorporated into the PMMA, and specimens were 3D-printed for tribological and bacterial analysis. The control specimens without ND fillers were tested against specimens with both amine-functionalized NDs (A-ND) and pure non-functionalized NDs (ND). The surface hardness test revealed a statistically significant increase in the Vickers micro-hardness (p 0.001) in the nanocomposite groups. There was a significant reduction in the coefficient of friction (COF) (p 0.01) in both the ND and A-ND nanocomposites compared to the stainless steel (SS) counter surfaces. However, for titanium (Ti)-based specimens, the COF of the control group was similar to that of A-ND but lower than that of ND. The wear resistance evaluation revealed that both the ND and A-ND groups displayed enhanced resistance to surface loss in comparison to the controls for both SS and Ti counter-surfaces (p 0.001). Furthermore, both A-ND and ND exhibited significantly enhanced resistance to the formation of Streptococcus mutans biofilms after 48 h (p 0.01) compared to the control group. Hence, we concluded that the addition of 0.1 wt% ND in the PMMA-based resin for 3D printing resulted in significant improvement in properties such as COF, wear resistance, and resistance to S. mutans, without any notable impact associated with the functionalization of the NDs.

Herein we evaluate the effect of nanodiamond (ND) incorporation on the mechanical properties of poly(methyl methacrylate) (PMMA) nanocomposite. Three quantities of ND (0.1, 0.3, and 0.5 wt.%) were tested against the control and zirconium oxide nanoparticles (ZrO). Flexural strength and elastic modulus were measured using a three-point bending test, surface hardness was evaluated using the Vickers hardness test, and surface roughness was evaluated using atomic force microscopy (AFM), while fungal adhesion and viability were studied using Candida albicans. Samples were also analyzed for biofilm thickness and biomass in a saliva-derived biofilm model. All groups of ND-PMMA nanocomposites had significantly greater mean flexural strengths and statistically improved elastic modulus, compared to the control and ZrO groups (P &lt, 0.001). The Vickers hardness values significantly increased compared to the control group (P &lt, 0.001) with 0.3% and 0.5% ND. ND addition also gave significant reduction in fungal adhesion and viability (P &lt, 0.001) compared to the control group. Finally, salivary biofilm formation was markedly reduced compared to the ZrO group. Hence, the incorporation of 0.1&ndash, 0.5 wt.% ND with auto- polymerized PMMA resin significantly improved the flexural strength, elastic modulus, and surface hardness, and provided considerable fungal resistance.

OBJECTIVE The aim of this study was to compare recycled and unused orthodontic miniscrews to determine the feasibility of reuse. The comparisons included both miniscrews with machined surfaces (MS), and those with etched surfaces (ES). METHODS Retrieved MS and ES were further divided into three subgroups according to the assigned recycling procedure: group A, air-water spray; group B, mechanical cleaning; and group C, mechanical and chemical cleaning. Unused screws were used as controls. Scanning electron microscopy, energy-dispersive X-ray spectrometry, insertion time and maximum insertion torque measurements in artificial bone, and biological responses in the form of periotest values (PTV), bone-implant contact ratio (BIC), and bone volume ratio (BV) were assessed. RESULTS Morphological changes after recycling mainly occurred at the screw tip, and the cortical bone penetration success rate of recycled screws was lower than that of unused screws. Retrieved ES needed more thorough cleaning than retrieved MS to produce a surface composition similar to that of unused screws. There were no significant differences in PTV or BIC between recycled and unused screws, while the BV of the former was significantly lower than that of the latter (p < 0.05). CONCLUSIONS These results indicate that reuse of recycled orthodontic miniscrews may not be feasible from the biomechanical aspect.

Poly(methyl methacralyate) (PMMA) has long been used in dentistry as a base polymer for dentures, and it is recently being used for the 3D printing of dental materials. Despite its many advantages, its susceptibility to microbial colonization remains to be overcome. In this study, the interface between 3D-printed PMMA specimens and oral salivary biofilm was studied following the addition of zwitterionic materials, 2-methacryloyloxyethyl phosphorylcholine (MPC) or sulfobetaine methacrylate (SB). A significant reduction in bacterial and biofilm adhesions was observed following the addition of MPC or SB, owing to their protein-repellent properties, and there were no significant differences between the two test materials. Although the mechanical properties of the tested materials were degraded, the statistical value of the reduction was minimal and all the properties fulfilled the requirements set by the International Standard, ISO 20795-2. Additionally, both the test materials maintained their resistance to biofilm when subjected to hydrothermal fatigue, with no further deterioration of the mechanical properties. Thus, novel 3D-printable PMMA incorporated with MPC or SB shows durable oral salivary biofilm resistance with maintenance of the physical and mechanical properties.

The increasing demand for orthodontic treatment over recent years has led to a growing need for the retrieval and reuse of titanium-based miniscrews to reduce the cost of treatment, especially in patients with early treatment failure due to insufficient primary stability. This in vitro study aimed to evaluate differences in the primary stability between initially inserted and re-inserted miniscrews within different cortical bone densities. Artificial bone was used to simulate cortical bone of different densities, namely 20, 30, 40, and 50 pound per cubic foot (pcf), where primary stability was evaluated based on maximum insertion torque (MIT), maximum removal torque (MRT), horizontal resistance, and micromotion. Scanning electron microscopy was used to evaluate morphological changes in the retrieved miniscrews. The MIT, MRT, horizontal resistance, and micromotion was better in samples with higher cortical bone density, thereby indicating better primary stability (P &lt, 0.05). Furthermore, a significant reduction of MIT, MRT, and horizontal resistance was observed during re-insertion compared with the initial insertion, especially in the higher density cortical bone groups. However, there was no significant change in micromotion. While higher cortical bone density led to better primary stability, it also caused more abrasion to the miniscrews, thereby decreasing the primary stability during re-insertion.

Objective: The purpose of this study was to analyze stress distributions in the roots, periodontal ligaments (PDLs), and bones around cylindrical and tapered miniscrews inserted at different angles using a finite element analysis. Methods: We created a three-dimensional (3D) maxilla model of a dentition with extracted first premolars and used 2 types of miniscrews (tapered and cylindrical) with 1.45-mm diameters and 8-mm lengths. The miniscrews were inserted at 30°, 60°, and 90° angles with respect to the bone surface. A simulated horizontal orthodontic force of 2 N was applied to the miniscrew heads. Then, the stress distributions, magnitudes during miniscrew placement, and force applications were analyzed with a 3D finite element analysis. Results: Stresses were primarily absorbed by cortical bone. Moreover, very little stress was transmitted to the roots, PDLs, and cancellous bone. During cylindrical miniscrew insertion, the maximum von Mises stress increased as insertion angle decreased. Tapered miniscrews exhibited greater maximum von Mises stress than cylindrical miniscrews. During force application, maximum von Mises stresses increased in both groups as insertion angles decreased. Conclusions: For both cylindrical and tapered miniscrew designs, placement as perpendicular to the bone surface as possible is recommended to reduce stress in the surrounding bone.

In this study, we aimed to assess the surface characteristics and the biomechanical stability of miniscrews with an anodic oxidized surface compared with machined surface miniscrews in beagle dogs.Self-drilled, titanium-aluminum-vanadium alloy miniscrews with an anodic oxidized surface (n = 48) or a machined surface (n = 48) were placed into the mandibles of 12 beagle dogs. The surface characteristics of both types of miniscrews were analyzed before implantation with scanning electron microscopy and atomic force microscopy. Insertion torque was measured during placement of all 96 miniscrews. Half of the implants in each group (24 specimens per subgroup) received 200 to 250 g of tensile force for 3-week or 12-week loading periods. Removal torque was measured in 12 specimens of each subgroup, and bone-implant contact and bone volume were quantified in the other 12 specimens of each subgroup.Atomic force microscopy measurements demonstrated that the anodic oxidized surface miniscrews had significantly higher roughness parameters than did the machined surface miniscrews (P 0.001). The 2 types of miniscrews were not significantly different in insertion and removal torque values or in bone-implant contacts and bone volumes, regardless of the loading period.Anodic oxidized miniscrews have different surface roughness profiles but no clinically significant superiority in biomechanical stability compared with machined surface miniscrews.

Significant progress has been made in endowing biomedical materials with antibacterial properties. However, the commercialization of these systems still poses various practical challenges. In this study, we report a facile technique for the preparation of practical and efficient antibacterial coatings based on well-defined polysilsesquioxane (PSQ) structures containing quaternary ammonium cation and long alkyl chains. PSQ is a hybrid material containing organic groups within a flexible and robust siloxane network, and can be endowed with different functions according to the synthetic conditions employed in the sol-gel process. However, depending on the synthetic precursors, a non-uniform PSQ structure can be formed, which limits the functions and stability of the resulting material. Accordingly, we synthesized PSQs with homogeneously distributed quaternary ammonium cation and long alkyl chains, using optimized synthetic conditions. The PSQs were coated on devices via self-assembly, and the thickness of the coating could be controlled from the nano- to the microscale depending on the deposition time. All coated substrates exhibited more than 60% bacterial reduction rate for three types of bacteria compared to the control groups. The coating inhibited the activity of the membrane adhesins, which prevented the strong adhesion of bacteria to the surfaces. Furthermore, the coated substrates also showed an increased mechanical strength in bulk strength tests. The nanoscale coatings notably increased the hardness of the dental substrates more than twofold compared to that of the control. The easy preparation and efficacy of the PSQs highlight their applicability as antibacterial coatings in various medical devices requiring high durability.

The creation of clinically patient-specific 3D-printed biomedical appliances that can withstand the physical stresses of the complex biological environment is an important objective. To that end, this study aimed to evaluate the efficacy of aminated nanodiamonds (A-NDs) as nanofillers in biological-grade acrylate-based 3D-printed materials. Solution-based mixing was used to incorporate 0.1 wt% purified nanodiamond (NDs) and A-NDs into UV-polymerized poly(methyl methacrylate) (PMMA). The ND and A-ND nanocomposites showed significantly lower water contact angles (p &lt, 0.001) and solubilities (p &lt, 0.05) compared to those of the control. Both nanocomposites showed markedly improved mechanical properties, with the A-ND-containing nanocomposite showing a statistically significant increase in the flexural strength (p &lt, 0.001), elastic modulus (p &lt, 0.01), and impact strength (p &lt, 0.001) compared to the control and ND-containing groups. The Vickers hardness and wear-resistance values of the A-ND-incorporated material were significantly higher (p &lt, 0.001) than those of the control and were comparable to the values observed for the ND-containing group. In addition, trueness analysis was used to verify that 3D-printed orthodontic brackets prepared with the A-ND- and ND-nanocomposites exhibited no significant differences in accuracy. Hence, we conclude that the successful incorporation of 0.1 wt% A-ND in UV-polymerized PMMA resin significantly improves the mechanical properties of the resin for the additive manufacturing of precisive 3D-printed biomedical appliances.

Based on three-dimensional scanning and computer-aided design and computer-aided manufacturing (CAD/CAM) techniques, customized bracket systems are increasingly used. However, data remain limited regarding customized bracket design, characteristics, and stability. This study was undertaken to evaluate the design, bond strength, and residual adhesives of four different CAD/CAM customized brackets that were attached to human tooth specimens by indirect bonding. Thirty extracted human upper premolars were divided into five groups: Group 1, preadjusted self-ligating labial metal bracket; Group 2, lingual self-ligating metal injection molding customized bracket; Group 3, gold-casted lingual customized bracket; Group 4, labial self-ligating milled customized bracket; Group 5, labial customized resin base bracket. Except in Group 1, premolar specimens were scanned via model scanner, and the images were sent to each manufacturing company to fabricate customized brackets and transfer trays/jigs. Debonding force (DF; N) was measured by Instron universal testing machine and shear bond strength (SBS; MPa) was calculated via dividing DF by bonding area. Adhesive remnants were analyzed via stereo microscopic images. Group 2 (196.90±82.75 N) exhibited significantly higher DF than Group 1 (62.77±12.65 N); other groups exhibited similar DFs, compared with Group 1. No customized bracket groups exhibited significant differences in SBS, relative to Group 1 (6.73±1.36 MPa). However, SBS in Group 5 (11.46±7.22 MPa) was significantly higher than in Group 3 (3.58±2.14 MPa). Group 3 had significantly lower ARI scores than other groups (P

The aim of this study was to evaluate whether combining two treatments to avoid biological aging of the surface of titanium and zirconia implants; i.e., storage in an aqueous solution after ultraviolet light (UV) or non-thermal atmospheric pressure plasma (NTP) treatment, yielded surface bioactivity comparable to that following post-15-min UV or NTP treatment storage under air or immediately after UV or NTP treatment. Grade IV titanium discs modified by large grit sand-blasting and acid-etching (SLA) and smooth zirconia discs were irradiated with UV or NTP and their surface properties were evaluated immediately and after storage for 8 weeks in distilled H2O (dH2O) and a sealed container under air. Approximately 15–30 nm-sized nano-protrusions were formed only on SLA surfaces in dH2O immediately after UV or NTP treatment. Immediate dH2O storage after UV or NTP treatment prevented hydrocarbon contamination and maintained elevated amounts of Ti and Zr. After 8 weeks, unlike zirconia, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on SLA surfaces stored in dH2O immediately after UV treatment were further exceeding those immediately after UV or NTP treatments. UV treatment of SLA implants followed by wet storage can not only maintain but also strengthen bioactivity during shelf storage.

In this work, we investigate the influence of grain boundaries on the performance of polycrystalline silicon thin-film transistors (poly-Si TFTs) for high resolution active-matrix organic light-emitting diode (AMOLED) displays using Voronoi diagram. The novel 2-D Voronoi polycrystalline grain structure can show a more realistic electrical parameter variability when the channel dimension is scaled down for high-resolution display. Using a proposed method, the impact of polycrystalline granular structure controlled by crystallization process is identified. Further, we predict the effect of grain boundary-induced variations under different laser annealing process, such as Excimer Laser Annealing (ELA).

Objective We evaluated whether the biological activity of the surface of titanium, when stored in an aqueous solution, in low vacuum, and under ambient conditions after ultraviolet light (UV) treatment is comparable to that of the surface immediately after UV treatment for 15 min and that after dielectric barrier discharge (DBD) plasma treatment for 15 min. Methods Grade IV titanium discs with machined surfaces were irradiated with UV and their surface properties were evaluated immediately and after storage for 28 days in distilled H 2 O (dH 2 O), a vacuum desiccator (31.325 kPa), and a sealed container under air. Their surface characteristics were evaluated by atomic force microscopy, X-ray diffraction, contact angle analysis, and X-ray photoelectron spectroscopy. Biological activities were determined by analyzing the albumin adsorption, MC3T3-E1 cell adhesion, and cytoskeleton development. Results Hydrophilicity of titanium surfaces stored in dH 2 O was comparable to that immediately after UV treatment and higher than that immediately after DBD plasma treatment ( P 0.001). Storage in dH 2 O and in low vacuum immediately after UV treatment prevented hydrocarbon contamination and maintained elevated amounts of titanium and oxygen. After 28 days, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on the titanium surfaces stored in dH 2 O were significantly enhanced compared to those stored in low vacuum and under ambient conditions while being comparable to those immediately after UV and DBD plasma treatments. Significance UV treatment of the titanium implants followed by wet storage is useful for maintaining enhanced biological activity and overcoming biological aging during shelf storage.

Calcium silicate-based cements (CSCs) are commonly used for endodontic procedures; however, their antibacterial effects are limited. The objective of this study was to develop a 2-methacryloyloxyethyl phosphorylcholine (MPC)-incorporated CSC with improved antibacterial properties, while maintaining the original advantageous features of CSC. MPC was incorporated into a commercial CSC (Endocem MTA) at 0 wt% (control), 1.5%, 3.0 wt%, 5.0 wt%, 7.5 wt%, and 10 wt%. The setting time, compressive strength, water sorption, and glycerol contact angle were measured. Protein absorption was measured and bacterial adhesion on the surface was evaluated using Enterococcus faecalis. The bactericidal effect was examined by the disc diffusion test. Mineralization ability was assessed based on calcium ion deposition, as assessed by alizarin red staining, after immersion into Hank's balanced salt solution for 7 days. High concentrations of MPC in CSC (7.5 wt% and 10 wt%) increased the setting time, reduced compressive strength, and reduced wettability. MPC (3 wt%) had greater protein repellent and anti-biofouling effects than those of control and test materials (P < 0.001). However, no bactericidal effect was observed for any control or test materials. There was greater calcium ion deposition on the surface of MPC-supplemented CSC than on the control (P < 0.001). The addition of 3 wt% MPC polymer to CSC confers protein-repellent properties and reduced bacterial attachment, with the potential for improved mineralization.

This study investigated the effect of pre-oxidation on the high-temperature oxidation behavior of Fe-Cr-Al powder porous metal. Using the powder metallurgy process, Fe-Cr-Al powder porous metals with and without pre-oxidation were manufactured. 24-hour TGA tests were conducted at three different temperatures: 900°C, 1000°C, and 1100°C. The high temperature oxidation results showed that pre-oxidized powder porous metal had even higher levels of oxidation resistance compared to that of porous metal without pre-oxidation regardless of the oxidation temperature. The weight gain of pre-oxidized porous metal (0.123%) was lowest at oxidation temperature of 900°C. In contrast, the weight gain of porous metals significantly increased at 1100°C. In the porous metals 900°C and 1000°C oxidized specimen, oxides such as Al2O3and Cr2O3were mainly observed. Porous metals oxidation specimen at 1100°C also revealed the presence of Fe-based oxides in large quantities in addition to the oxides formed at lower temperature.

This study investigated the high temperature oxidation of Ni–Fe–Cr–Al porous metal. Two types of open porous metals with pore sizes of 30 and 40 PPI were used. For 24-h, the isothermal oxidation TGA tests were conducted at three different temperatures of 900, 1000, and 1100 °C. The oxidation resistance of porous metal decreased with decreasing pore size. Porous metals mainly created oxides such as Al2O3, Cr2O3, NiAl2O4, and NiCr2O4. The porous metal represented increasingly faster dwindling of Al and Cr content and easy progress to internal oxidation, comparing to the oxidation of bulk metal.

OBJECTIVE: To evaluate the structural stability of anodic oxidation treatment of miniscrews during a self-drilling procedure and an initial loading period. MATERIALS AND METHODS: Eight orthodontic miniscrews with a machined surface and an anodic oxidized surface were placed in the mandible of two beagle dogs. With all miniscrews, an orthodontic force was applied immediately after placement and was continued for 12 weeks. After beagle dogs were sacrificed, the miniscrews were carefully removed from decalcified bone fragments. Miniscrews were evaluated by comparing and quantitatively analyzing changes in surface roughness of unused and used miniscrews (machined surface vs anodic oxidized surface) utilizing both scanning electron microscopy (SEM) and atomic force microscopy (AFM). RESULTS: SEM revealed that only a thread edge close to the tip of the used anodic oxidized miniscrew became smooth by smearing, compared with the unused anodic oxidized miniscrew. No definite changes were observed in the thread valleys of the two groups after placement. AFM measurements demonstrated that all surface roughness parameters of thread edges of the used anodic oxidized miniscrews were significantly reduced compared with the unused anodic oxidized miniscrew (P < .05). A middle thread edge of the used anodic miniscrew surface was rougher than the unused and used machined surface miniscrews (P < .05). CONCLUSION: Anodic oxidized miniscrews had improved surface characteristics compared with machined surface miniscrews, even if the surface texture was changed by the self-drilling procedure and during the initial loading period.

In this study, cast bulk specimens and powder sintered specimens were produced from a Fe-22% Cr-5.8% Al alloy, which has been drawing industrial attention for its outstanding high-thermal and oxidation resistance as well as for its applicability as a filter and support material. The high-temperature oxidation behaviors of the specimens were compared and analyzed. Two types of specimens were subjected to 24-hour isothermal oxidation (temperatures of 900 °C, 1000 °C, and 1100 °C and a gas atmosphere of 79% N2+21% O2) to understand their high-temperature oxidation properties. The oxidized specimens were examined via X-ray, SEM, FE-SEM, and EPMA for microstructure and oxide analyses. The results of the oxidation tests showed that both bulk and powder-sintered specimens gained weight as temperature increased, with the powder sintered specimens gaining far more weight than the bulk specimens. As the temperature increased, the bulk specimens showed sequential formation of Al2O3, Cr2O3, and Fe3O4 oxide layers. The stable Al2O3 on the surface of the bulk specimens was found to play a role in arresting the rapid growth of oxide layers. In the powder-sintered specimens, however, the internal diffusion of O2 easily took place along the powder interfaces. As a result, far more oxidation occurred in the powder-sintered specimens than in the bulk specimens. Cracks and disintegration of the oxide layers were also found to have occurred as the temperature increased. The high-temperature oxidation mechanisms of bulk and powder-sintered materials in relation to temperature increase are further discussed.

【This study investigated the high temperature oxidation behavior of Ni-22.4%Fe-22%Cr-6%Al (wt.%) porous metal. Two types of open porous metals with different pore sizes of 30 PPI and 40 PPI (pore per inch) were used. A 24-hour TGA test was conducted at three different temperatures of $900^{\circ}C$ , $1000^{\circ}C$ and $1100^{\circ}C$ . The results of the BET analysis revealed that the specific surface area increased as the pore size decreased from 30 PPI to 40 PPI. The oxidation resistance of porous metal decreased with decreasing pore size. As the temperature increased, the oxidation weight gain of the porous metal also increased. Porous metals mainly created oxides such as $Al_2O_3$ , $Cr_2O_3$ , $NiAl_2O_4$ , and $NiCr_2O_4$ . In the 40 PPI porous metal with small pore size and larger specific surface area, the depletion of stabilizing elements such as Al and Cr occurred more quickly during oxidation compared to the 30 PPI porous metal. Ni-Fe-Cr-Al porous metal's high-temperature oxidation micro-mechanism was also discussed.】

This study investigated the effect of the pore size of Ni-22.4%Fe-22%Cr-6%Al porous metal on its hightemperature oxidation. Two types of open porous metals with pore sizes of 800 μm and 580 μm were used. A 24-hour isothermal oxidation test was conducted at three different temperatures of 900 °C, 1000 °C, and 1100 °C under a 79% N2 + 21% O2 atmosphere. The results of the BET analysis revealed that the specific surface area increased as the pore size decreased from 800 μm to 580 μm. The high-temperature oxidation results showed that porous metals exhibited far lower levels of oxidation resistance compared with bulk metals, and that the oxidation resistance of porous metals decreased with a decreasing pore size. According to the microstructural observations of the oxide layers, the 900 °C and 1000 °C oxidation layer contained Ni, Cr, and Al oxides mainly on the strut. The 800 μm porous metal strut exhibited similar oxidation behavior at 1100 °C to that found at lower temperatures. In contrast, the 580 μm porous metal strut was found to consist of Ni and Fe oxides in the upper layer and Ni, Cr, and Al oxides in the lower layer, representing a low oxidation resistance. For powders affixed to the strut inside the porous metal, a different oxide-forming behavior from that of the strut was observed. In addition, the Ni-Fe-Cr-Al porous metal high-temperature oxidation microscopic mechanism is also discussed.

This study investigated the high temperature oxidation behavior of Fe-22%Cr-5.8%Al alloy and the oxidation kinetics of the alloy were discussed. Bulk samples were prepared by VAM (vacuum arc melting) and hot forging. High temperature oxidation testes were isothermally conducted up to 100 hours in 79%+21% environment at three different temperatures (, , ). The weight gain was measured after oxidation according to oxidation time (2, 4, 6, 8, 10, 15, 20, 25, 30, 60, 80, 100 hours). The weight gain significantly increased with increasing oxidation temperature. As the temperature increased, the oxidized samples showed sequential formation of , Cr-rich oxide, Fe-rich oxide. The activation energy of high temperature oxidation was obtained as 306.63 KJ/mol. were developed on the surface in the early stage of oxidation, representing protective role of oxidation. However, Fe-based and Cr-based oxides leaded to breakaway of oxide layer, thus resulted in the significant increase of additional oxidation.

This study attempted to investigate the high temperature tensile deformation behaviour of new Al-1%Mg-1.1%Si0.8%CoNi heat resistant aluminium alloy. New aluminium alloy strengthened by Co-Ni based phase was manufactured by using powder ball milling and continuous casting, based on the alloy design & preliminary test. High temperature tensile tests were conducted at various temperatures from 25�� to 450�� . OM, SEM, EPMA, XRD, FIB and HR-TEM equipments were used to analyse microstructure, phases, and fracture surface. Microstructure of the new alloy mainly consisted of Al matrix and Co-Ni based phases (1~8 Πm). The Co-Ni based phase was analyzed and confirmed as (Ni, Co)3Al having incoherent interface with matrix. In high temperature tensile results, the new aluminium alloy didn’t show significant decrease (19.6%) of strength with increasing temperature (450�E ), suggesting totally different behaviour with conventional A319 alloy (87.0% decrease of T.S.). Fractography observation results of new alloy represented the ductile fracture mode with dimples. Voids were mainly initiated at Co-Ni based strengthening phases. It was apparently observed that the strengthening effect of the (Ni, Co)3Al could be still maintained at high temperature of 450�� . The deformation mechanism of this alloy was also discussed. © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ICM11

We have investigated electrical characteristics of laser-crystallized polycrystalline silicon thin film transistors (poly-Si TFTs) under various stresses such as bias, temperature, light illumination. The threshold voltage of short channel TFT (LCH=1.5μm) was significantly shifted to negative direction due to bias temperature stress (ΔVTH = -3.75V) compared with that of long channel TFT (ΔVTH = -0.32V) at 100{degree sign}C. We have also investigated the effects of light illumination on the laser-crystallized poly-Si TFT. In order to improve the reliability of laser-crystallized poly-Si TFT, a novel multiple-channel structure was proposed and fabricated without any additional processes. In addition, in order to enhance the electric characteristics and stability of alternating magnetic-field-enhanced rapid thermal annealing (AMFERTA) poly-Si TFTs, we have employed the NH3 plasma pretreatment prior to crystallization process. The NH3 plasma pretreatment process could effectively improve the reliability of AMFERTA poly-Si TFTs.

Previous diagnosing methods based on agglutination have a limitation in view of emergency and point-of-care diagnoses due to the requirement of large scale equipments and much agglutination time. In this paper, we propose a low cost microfluidic lab-on-a-chip for more efficient detection of agglutination. In the present lab-on-a-chip, two inlet microwells, flow guiding microchannels, chaotic micromixer and reaction microwell are fully integrated. Mold inserts for the lab-on-a-chip were manufactured by UV photolithography and nickel electroplating process. The complete lab-on-a-chip was realized by the microinjection molding of cyclic olefin copolymer and the subsequent thermal bonding. The improved serpentine laminating micromixer, developed by our group, integrated in the lab-on-a-chip showed the high-level of chaotic mixing, thereby enabling us to get a reliable mixing of sample and reagent. The performance of the fabricated lab-on-a-chip was demonstrated by agglutination experiments with simulated bloods of 10 μl and simulated sera of 10 μl. The results of agglutination inside the reaction microwell were clearly read by means of the level of light transmission. The present microfluidic lab-on-a-chip could be widely applied to various clinical diagnostics based on agglutination tests.

The hysteresis phenomenon of both a-Si and poly-Si TFT has been studied in order to investigate the hystersis phenomenon effect on residual image of AMOLED display. The transfer characteristics of both a-Si:H TFT and poly-Si TFT were varied according to the gate voltage sweep direction due to the different initial interface trapped charges in the gate insulator. The threshold voltage in a-Si:H TFT was altered by 0.23V due to hysteresis of device according to gate sweep direction while that in poly-Si TFT was varied by 0.21V due to the different gate insulator. In order to suppress hystersis effect on OLED current error we proposed and fabricated a new pixel circuit. By applying the reset voltage in pixel circuit, the data voltage sweep direction could be fixed and hysteresis effect on OLED current error was successfully suppressed. We showed that the OLED current error was successfully suppressed by experiment.

Highly stable voltage programmed a-Si:H TFT pixel circuit for AMOLED, which employs both Vth-compensation and negative bias annealing, is proposed and fabricated. Experimental results, after 60 hours electrical stress at elevated temperature (60°C) show that the OLED current stability in the proposed pixel is considerably improved compared with a conventional 2-TFT pixel, Vth-compensated pixel, and negative bias annealed pixel, respectively. The proposed pixel can reduce the degradation of a-Si:H TFT by employing negative bias annealing store Vth of a-Si:H TFT so that highly stable and uniform a-Si:H TFT backplane for AMOLED. Our proposed pixel may be suitable for highly stable AMOLED employing the a-Si:H TFT.

Proton irradiation technology was used for improvement of switching characteristics of the PT-IGBT. Proton irradiation was carried out at 5.56 MeV energy with doze from the back side of the wafer. The I-V, breakdown voltage, and turn-off delay time of the device were analyzed and compared with those of un-irradiated device and e-beam irradiated device which was conventional method for minority carrier lifetime reduction. For proton irradiated device, the breakdown voltage and the on-state voltage were 733 V and 1.85 V which were originally 749 V and 1.25 V, respectively. The turn-off time has been reduced to 170 ns, which was originally for the un-irradiated device. The proton irradiated device was superior to e-beam irradiated device for the breakdown voltage and the on-state voltage which were 698 V and 1.95 V, respectively, nevertheless turn-off time of proton irradiated device was reduced to about 60 % compared to that of the e-beam irradiated device.

Agglutination is one of the most commonly employed reactions in clinical diagnosis. In this paper, we have designed and fabricated nickel mold insert for injection molding of a microfluidic lab-on-a-chip for the purpose of the efficient detection of agglutination. In the presented microfluidic lab-on-a-chip, two inlets for sample blood and reagent, flow guiding microchannels, improved serpentine laminating micromixer(ISLM) and reaction microwells are fully integrated. The ISLM, recently developed by our group, can highly improve mixing of the sample blood and reagent in the microchannel, thereby enhancing reaction of agglutinogens and agglutinins. The reaction microwell was designed to contain large volume of about of the mixture of sample blood and reagent. The result of agglutination in the reaction microwell could be determined by means of the level of the light transmission. To achieve the cost-effectiveness, the microfluidic lab-on-a-chip was realized by the injection molding of COC(cyclic olefin copolymer) and thermal bonding of two injection molded COC substrates. To define microfeatures in the microfluidic lab-on-a-chip precisely, the nickel mold inserts of lab-on-a-chip for the injection molding were fabricated by combining the UV photolithography with a negative photoresist SU-8 and the nickel electroplating process. The microfluidic lab-on-a-chip developed in this study could be applied to various clinical diagnosis based on agglutination.

We have designed and fabricated poly-Si TFTs employing various counter-doped lateral body terminals (LBT) which suppress a kink current and improve the reliability under the various electrical stresses. Our experimental results show that the TFT with a LBT structure connected near the drain region was more effective to suppress the kink current and to reduce the leakage current. The suppression of the kink effect employing LBT structure can be attributed to the decrease of E-field at the drain junction due to the potential redistribution in the channel of the TFT by the counter doped LBT and the collecting holes, which have been generated by impact ionization at the drain.

Aminofunctional organosilanes, such as 3-aminopropyltriethoxysilane (APTES), have been widely utilized as adhesion promoters, and have also been found to have the ability to prevent dewetting of polymer thin films from substrates. The APTES molecule contains an active terminal amino group that can hydrogen bond with the multiple hydroxylated head groups in itself and hydroxyl groups on a substrate, thus forming cyclic structures and a complex loose network at ambient conditions. Upon heating, the hydrogen bond can be broken, allowing more silanol groups to condense with each other and form siloxane linkages, hence tightening the three-dimensional network. When a polymer thin film is in contact with the APTES layer during the thermal process, the polymer chains can diffuse/penetrate into the APTES network while the network is being tightened by the additional crosslinking. The penetrated and subsequently anchored chains could help to stabilize the thin film on the substrate. This hypothesis was verified by dewetting studies of thin films of polystyrene (PS), having molecular weights above and below the entanglement molecular weight ( M e ), from APTES and control surfaces when the systems were subjected to various treatments. Dewetting suppression was observed for PS/APTES that was thermally treated at ∼80 °C or 120 °C prior to the annealing of the thin film at higher temperatures. Much stronger suppression was noticed for PS having a molecular weight higher than M e . When PS thin films were deposited onto a precured APTES network, no dewetting suppression was observed.

We designed and fabricated highly reliable multiple-channel indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) without any additional fabrication processes. We also investigated the geometric factors of the multiple-channel structure that influence the reliability of the IGZO TFTs in high saturation mode, such as the spacing and width of the subchannels. The proposed device exhibited superior reliability(ΔVTH

Gradient surfaces are widely employed in biological studies for protein adsorption and cell attachment and growth. They also offer great potential in the areas of fluid flow and combinatorial experimental design for obtaining material properties and behaviors. Gradient surfaces are created with organosilanes by using the diffusion techniques proposed by Ewling and modified by Chaudhury. However, these techniques have limitations. They either generate a significant amount of organic waste or require well-controlled deposition conditions. In this paper, we propose a fast, convenient, reproducible, and inexpensive method that generates gradient surfaces with minimum waste generation. Particularly, we have adopted Whitesides's contact-printing technique to achieve a gradient by gradually varying the contact time over the contacted area using octadecyltrichlorosilane. Elastomeric stamps with different geometries and various radii of curvature are used to generate gradient surfaces at both millimeter and microm...

We investigated the effect of the deposition temperature on the electrical performance of SiOx passivation layers for amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO TFTs). Compared to the time-of-flight secondary ion mass spectroscopy depth profile of the IGZO film with a SiOx passivation layer deposited at low temperature (150oC ), that with the SiOx film formed at 300oC exhibited the significant migration of metal ions from the IGZO film into the SiOx passivation layer. These results were attributed to the high-energy ion bombardment on the IGZO channel layer. In order to suppress the interdiffusion of In, Ga, and Zn atoms between the IGZO and passivation layers, we proposed double SiOx passivation using different substrate temperatures. It combines the merits of low-temperature (150oC) and high-temperature (300oC) passivations and compensates for their individual weaknesses. We confirmed the enhanced electrical characteristics and improved reliability of the IGZO TFTs compared to those of the conventional device.

Objective: To investigate the three-dimensional structural features of three types of mechanically retentive ceramic bracket bases. Materials and Methods: One type of stainless steel (MicroArch, Tomy, Tokyo, Japan) and three types of ceramic maxillary right central incisor brackets—Crystaline MB (Tomy), INVU (TP Orthodontics, La Porte, Ind), and Inspire Ice (Ormco, Glendora, Calif)—were tested to compare and quantitatively analyze differences in the surface features of each ceramic bracket base using scanning electron microscopy (SEM), a three-dimensional (3D) optical surface profiler, and microcomputed tomography (micro-CT). One-way analysis of variance was used to find differences in bracket base surface roughness values and surface areas between groups according to base designs. Tukey's honestly significant differences tests were used for post hoc comparisons. Results: SEM revealed that each bracket exhibited a unique surface texture (MicroArch, double mesh; Crystaline MB, irregular; INVU, single mesh; Inspire Ice, bead ball). With a 3D optical surface profiler, the stainless steel bracket showed significantly higher surface roughness values. Crystaline MB had significantly higher surface roughness values than Inspire Ice. Micro-CT demonstrated that stainless steel brackets showed significantly higher whole and unit bracket base surface areas. Among ceramic brackets, INVU showed significantly higher whole bracket base surface area, and Crystaline MB showed a significantly higher unit bracket base surface area than Inspire Ice. Conclusion: Irregular bracket surface features showed the highest surface roughness values and unit bracket base surface area among ceramic brackets, which contributes to increased mechanically retentive bracket bonding strength.

We have investigated the stability of short channel (1.5μm) p-Type polycrystalline silicon (poly-Si) Thin Film Transistors (TFTs) on the glass substrate under AC bias stress. The variation of threshold voltage in short channel poly-Si TFT was considerably higher than that of long channel poly-Si TFT. Threshold voltage of the short channel TFT was considerably moved to the positive direction during AC bias stress, whereas the threshold voltage of a long channel was rarely moved. The variation of threshold voltage in the short channel p-type TFT under AC bias stess was more compared to that under DC bias stress. The threshold voltage of short channel (L=1.5μm) poly-Si TFT was increased about -7.44V from -0.305V to -7.745V when VGS = 5 (base value) ~ -15V (peak value), VDS = -15V was applied for 3,000 seconds. This positive shift of threshold voltage and significantly degraded s-swing value in the short channel TFT under dynamic stress (AC) may be due to the increase of the stress-induced trap state density at gate insulator / channel interface region.

We successfully fabricated a-IGZO TFTs employing a Ti/Cu source/drain (S/D) and SiNx passivation in order to reduce the line-resistance, as compared to most oxide TFTs that use Mo (or TCO) and SiO2 for their S/D and passivation, respectively. Although passivated with SiNx, the TFT exhibits good transfer characteristics without a negative shift. However, the TFT employing a Mo S/D exhibited conductor-like characteristics when passivated with SiNx. Our investigation suggests that the IGZO oxygen vacancies found in the Ti/Cu S/D are controlled, resulting in low concentrations, and so prevent the SiNx-passivated TFT from having a negative shift.

We have propsed MgO/AZO bi-layer transparent conducting oxide (TCO) for thin film solar cells. From XRD analysis, it was observed that the full width at half maximum of AZO decreased when it was grown on MgO precursor. The Hall mobility of MgO/AZO bi-layer was 17.5cm2/Vs, whereas that of AZO was 20.8cm2/Vs. These indicated that the crystallinity of AZO decreased by employing MgO precursor. However, the haze (=total diffusive transmittance/total transmittance) characteristics of highly crystalline AZO was significantly improved by MgO precursor. The average haze in the visible region increased from 14.3 to 48.2%, and that in the NIR region increased from 6.3 to 18.9%. The reflectance of microcrystalline silicon solar cell was decreased and external quantum efficiency was significantly improved by applying MgO/AZO bi-layer TCO. The efficiency of microcrystalline silicon solar cell with MgO/AZO bi-layer front TCO was 6.66%, whereas the efficiency of one with AZO single TCO was 5.19%.

Al-doped ZnO (AZO) films with different boron (B) content have been prepared on glass substrates by co-sputtering of AZO (2wt. % Al 2 O 3 ) and B-doped ZnO (BZO, 3wt. % B 2 O 3 ) targets at room temperature. The B content in the B-doped AZO (BAZO) film was controlled by DC power on BZO target. X-ray diffraction analysis indicated that the B-doping improved the crystalline structure of AZO film. Hall measurement analysis showed that resistivity of BAZO films was lowered to 2.06×10−3 Ω·cm, whereas that of AZO film was 5.68×10−3 Ω·cm. Hall mobility of AZO film was improved with appropriate B-doping, and carrier concentration was increased with B-doping due to B activation as a donor.

We have investigated the effects of hydrogen plasma treatment on the hysteresis phenomenon and electrical properties of solid phase crystallized silicon thin film transistors (SPC-Si TFTs) employing alternating magnetic field crystallization (AMFC). We employed H2 plasma treatment on the SPC-Si active layer before SiO2 gate insulator deposition. By increasng the power and time duration of H2 plasma treatment, it was observed that hysteresis phenomenon of SPC-Si TFT was suppressed and electrical properties such as threshold voltage, field effect mobility was improved considerably. This is due to role of hydrogen atom by passivating the defects and grain boundary trap states in SPC-Si film. However, relatively high power and long hydrogen plasma treatment (100W, 5 minutes) could degrade the electrical characteristics of the device. SPC-Si TFT for 100W power of PECVD and 3 minutes with the H2 plasma treatment exhibit the significant improvement of electrical characterics (VTH = - 3.85V, μFE = 21.16cm2/Vs), and a smaller hysteresis phenomenon (∆VTH = -0.30V) which is suitable for high quality AMOLED Display.

We have fabricated the new top gate depletion mode n-type alternating magnetic field enhanced rapid thermal annealing (AMFERTA) polycrystalline silicon (poly-Si) thin film transistors (TFTs), which show the excellent electrical characteristics and superior stability compared with hydrogenated amorphous silicon (a-Si:H) TFTs and excimer laser crystallized (ELC) low temperature polycrystalline silicon (LTPS) TFTs. The fabricated AMFERTA poly-Si TFTs were not degraded under hot-carrier stress, and highly biased vertical field stress. The considerably large threshold voltage shift (ΔVTH) and trap state density reducing were occurred when the gate bias and drain bias were both large enough. The dominant mechanism of instability in the fabricated depletion mode AMFERTA poly-Si TFTs may be due to carrier induced donor-like defects reduction within the channel layer, especially near the drain junction.

We have investigated temperature dependence on the hysteresis phenomenon of SLS poly-Si TFT on a glass substrate, extremely at low temperature (213K). The p-type sequential lataral solidification (SLS) polycrystalline Silicon (poly-Si) TFT was fabricated on glass substrate. As the temperature was reduced, it was observed that hysteresis phenomenon was increased, whereas the hysteresis was suppressed at high temperature. This could be explained by a difference of initially electron and hole trapped charges into gate insulator is much larger in low temperature than in high temperature. And we have verified that drain current was changed with a different previous gate starting voltage even at same bias condition by experimental results due to the hysteresis phenomenon of SLS poly-Si TFT. Hysteresis of SLS poly-Si TFT should be improved for a pixel element of high quality AMOLED display.