Organic Fluorophore Coated Polycrystalline Ceramic LSO:Ce Scintillators for X-ray Bioimaging.

The current effort demonstrates that lutetium oxyorthosilicate doped with 1-10% cerium (Lu2SiO5:Ce, LSO:Ce) radioluminescent particles can be coated with a single dye or multiple dyes and generate an effective energy transfer between the core and dye(s) when excited via X-rays. LSO:Ce particles were surface modified with an alkyne modified naphthalimide (6-piperidin-1-yl-2-prop-2-yn-1-yl-1 H-benzo[ de]isoquinoline-1,3-(2 H)-dione, AlNap) and alkyne modified rhodamine B ( N-(6-diethylamino)-9-{2-[(prop-2-yn-1-yloxy)carbonyl]phenyl}-3 H-xanthen-3-ylidene)- N-ethylethanaminium, AlRhod) derivatives to tune the X-ray excited optical luminescence from blue to green to red using Förster Resonance Energy Transfer (FRET). As X-rays penetrate tissue much more effectively than UV/visible light, the fluorophore modified phosphors may have applications as bioimaging agents. To that end, the phosphors were incubated with rat cortical neurons and imaged after 24 h. The LSO:Ce surface modified with AlNap was able to be successfully imaged in vitro with a low-output X-ray tube. To use the LSO:Ce fluorophore modified particles as imaging agents, they must not induce cytotoxicity. Neither LSO:Ce nor LSO:Ce modified with AlNap showed any cytotoxicity toward normal human dermal fibroblast cells or mouse cortical neurons, respectively.

Iatrogenic foreign body in urinary bladder: Holmium laser vs. Ceramic, and the winner is .

INTRODUCTION: Urological surgery is estimated to be the third most common cause of iatrogenic-retained foreign bodies (1). PRESENTATION: A 76-year old man was undergoing a transurethral resection of bladder tumor with a 26-Ch continuous flow resectoscope (Karl Storz, Germany). Before starting resection, a detachment of resectoscope sheath tip was noted. The ceramic tip was free-floating in the bladder lumen, and it would not fit within the sheath, making direct extraction using the loop impossible. An attempt was made to break it with a stone punch, but it was unsuccessful due to impossibility of closing it in the branches. Therefore, we decided to fragment the tip with holmium laser (RevoLix®, LISA Laser products, Germany), using an 800-micron, front-firing fiber. Laser device was settled at with 2.5 J energy and 5 Hz frequency. Ceramic appeared very hard, but it was difficult to carry on breaking with this setting because of tip retropulsion. Then, laser setting was switched to lower energy and higher frequency (1 J and 13 Hz). This setting guaranteed the same power of 13 W, but with minimal retropulsion. RESULTS: Tip was fragmented against the posterior bladder wall in seven pieces, which were retrieved trough the outer sheath. A total 5.62 kJ were used to fragment it. At the end, superficial lesions of the posterior bladder wall were highlighted. Surgical time was 55 minutes. Patient was discharged home next day without problems. CONCLUSIONS: Holmium laser fragmentation is a safe and effective approach to remove foreign bodies from the bladder.

Nd:YAG Laser Treatment of Bioglass-coated Zirconia Surface and Its Effect on Bond Strength and Phase Transformation.

PURPOSE: To evaluate the morphological properties, phase transformation, and microshear bond strength of composite cement to bioglass-coated zirconia surfaces treated with Nd:YAG laser. MATERIALS AND METHODS: Seventy-five zirconia disks were divided into five groups (n = 15). Group C received no surface treatment (control). Group S was subjected to sandblasting with 50-µm aluminum oxide particles. Group B samples were coated with bioglass 45S5. Groups BL9 and BL5 received bioglass coating and laser irradiation with 9 J/cm2 and 5 J/cm2 energy density. Morphological assessment was done using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Zirconia phase transformation was assessed by XRD. Microhear bond strength testing was performed using a modified microtensile tester. The data were analyzed using the Welch test and the Games-Howell test (p < 0.05). RESULTS: The sandblasted and bioglass-coated groups showed the highest bond strengths compared to other groups (p < 0.05). Group S showed the highest surface roughness and the highest frequency of cohesive failure. In all samples, the tetragonal phase decreased after surface treatment. Groups BL9 and BL5 showed some levels of tetragonal to cubic phase transformation. CONCLUSION: Bioglass coating of zirconia surfaces (using the slurry method) can increase its microshear bond strength comparable to that of sandblasting. Surface roughness of sandblasted zirconia was the highest among all methods. Irradiation of Nd:YAG laser on bioglass-coated zirconia surfaces is not effective and decreases its bond strength compared to sandblasting and bioglass coating. Increasing the Nd:YAG laser energy density cannot increase the surface roughness of bioglass-coated zirconia surfaces. Bioglass coating results in transformation of the tetragonal to the cubic phase.

Shear bond, wettability and AFM evaluations on CO2 laser-irradiated CAD/CAM ceramic surfaces.

The purpose of this study is to determine the CO2 laser irradiation in comparison with sandblasting (Sb), hydrofluoric acid (Hf) and silane coupling agent (Si) on shear bond strength (SBS), roughness (Rg) and wettability (Wt) of resin cement to CAD/CAM ceramics. Sixty (CAD/CAM) ceramic discs were prepared and distributed into six different groups: group A, control lithium disilicate (Li); group B, control zirconia (Zr); group C, Li: CO2/HF/Si; group D, Li: HF/Si; group E, Zr: CO2/Sb/Si; group F, Zr: Sb/Si. Result showed significant difference between irradiated and non-irradiated in terms of shear bond strength for zirconia ceramics (p value = 0.014). Moreover, partial surface wettability for irradiated and non-irradiated ceramics. Irradiated surface demonstrated more rough surface in lithium disilicate than zirconia ceramics. CO2 irradiation could increase shear bond strength, surface roughness and wettability for both CAD/CAM ceramics.

Influence of Light Irradiation Through Zirconia on the Degree of Conversion of Composite Cements.

PURPOSE: To assess the light irradiance (LI) delivered by two light-curing units and to measure the degree of conversion (DC) of three composite cements and one flowable composite when cured through zirconia or ceramic-veneered zirconia plates with different thicknesses. MATERIALS AND METHODS: Three dual-curing composite cements (Clearfil Esthetic Cement, Panavia F2.0, G-CEM LinkAce) and one light-curing flowable composite (G-aenial Universal Flo) were investigated. Nine different kinds of zirconia plates were prepared from three zirconia grades (YSZ: Aadva and KATANA; Ce-TZP/Al2O3: NANOZR) in three different thicknesses (0.5- and 1.5-mm-thick zirconia, and 0.5-mm-thick zirconia veneered with a 1.0-mm-thick veneering ceramic). Portions of the mixed composite cements and the flowable composite were placed on a light spectrometer to measure LI while being light cured through the zirconia plates for 40 s using two light-curing units (n = 5). After light curing, micro-Raman spectra of the composite films were acquired to determine DC at 5 and 10 min, 1 and 24 h, and at 1 week. RESULTS: The zirconia grade and the thickness of the zirconia/veneered zirconia plates significantly decreased LI. Increased LI did not increase DC. Only the Ce-TZP/Al2O3 (NANOZR) zirconia was too opaque to allow sufficient light transmission and resulted in significantly lower DC. CONCLUSION: Although zirconia-based restorations attenuate the LI of light-curing units, the composite cements and the flowable composite could be light cured through the YSZ zirconia. LI is too low through Ce-TZP/Al2O3 zirconia, necessitating the use of self-/dual-curing composite cements.

Effect of engraving speeds of CO2 laser irradiation on In-Ceram Alumina roughness: a pilot study.

OBJECTIVES: The aim of the study was to determine the effect of CO2 laser on surface roughness of In-Ceram-Alumina-ceramic. MATERIALS AND METHODS: Four aluminum-oxide ceramic disc specimens were prepared of In-Ceram Alumina. Discs received CO2 laser irradiation with different engraving speeds (100, 400, 600 and 800 mm/min) as a surface treatment. The roughness of the surfaces was measured on digital elevation models reconstructed from stereoscopic images acquired by scanning-electron-microscope. Surface roughness data were analyzed with One-Way-Analysis-of-Variance at a significance level of p<0.05. RESULTS: There was no significant difference between the roughness values (p=0.82). Due to higher laser durations, partial melting signs were observed on the surfaces. Tearing, smearing and swelling occurred on melted surfaces. Swelling accompanying melting increased the surface roughness, while laser power was fixed and different laser engraving speeds were applied. CONCLUSION: Although different laser irradiation speeds did not affect the roughness of ceramic surfaces, swelling was observed which led to changes on surfaces.

Quantification of the amount of blue light passing through monolithic zirconia with respect to thickness and polymerization conditions.

STATEMENT OF PROBLEM: Dual-polymerized luting composite resin cements would benefit from enhanced irradiance transmitted through a ceramic restoration. A quantification of the amount of transmitted light through translucent zirconia is lacking. PURPOSE: The purpose of this study was to evaluate the amount of light (360 to 540 nm) passing through translucent and conventional zirconia and a glass ceramic with respect to material thickness and different polymerizing modes. MATERIAL AND METHODS: Six translucent and a conventional zirconia (negative control) and a glass ceramic (positive control) were considered. Ten specimens of each material and thickness (.5, 1, 1.5, 2, 2.5, 3 mm) were fabricated (n=480). Zirconia materials were sintered according to manufacturers' instructions. The irradiance passing the different ceramics and thicknesses was measured with a violet-blue LED polymerizing unit in 3 polymerizing modes (plasma, high, and standard power mode) with a USB4000 Spectrometer. The polymerizing unit was placed directly on the specimen's surface. Data were analyzed with one and multivariate analysis and the Pearson correlation analysis (α=.05). RESULTS: In all materials, the translucency and its rate decreased exponentially according to the specimen thickness. The highest influence on the measured irradiance passing through translucent zirconia was exerted by ceramic thickness (P<.05, partial eta squared [ηP²]=.998), closely followed by polymerizing mode (ηP²=.973), while the effect of the material (P=.03, ηP²=.06) and mean grain size (P=.029, ηP²=.027) was significant but low. CONCLUSIONS: Zirconia was less translucent than the glass ceramic, but the translucency decreased more slowly with material thickness, thus approaching the translucency of glass ceramics at a specimen thicknesses of 2.5 to 3 mm.

Influence of hydrophilic pre-treatment on resin bonding to zirconia ceramics.

Atmospheric plasma or ultraviolet (UV) treatment alters the surface characteristics of tetragonal zirconia polycrystal (TZP), increasing its hydrophilicity by reducing the contact angle against water to zero. This suggests that such treatment would increase the wettability of bonding resin. The purpose of this study was to determine how increasing the hydrophilicity of TZP through plasma irradiation, UV treatment, or application of ceramic primer affected initial bonding with resin composites. Here, the effect of each pre-treatment on the hydrophilicity of TZP surfaces was determined by evaluating change in shear bond strength. Plasma irradiation, UV, or ceramic primer pre-treatment showed no significant effect on bonding strength between TZP surfaces and resin composites. In addition, alumina blasting yielded no significant increase in bond strength. Plasma irradiation, UV treatment, or ceramic primer pre-treatment did not lead to significant increase in bond strength between TZP and resin composites.

High-efficiency diode-pumped actively Q-switched ceramic Nd:YAG/BaWO4 Raman laser operating at 1666 nm.

A diode-pumped actively Q-switched Raman laser employing BaWO4 as the Raman active medium and a ceramic Nd:YAG laser operating at 1444 nm as the pump source is demonstrated. The first-Stokes-Raman generation at 1666 nm is achieved. With a pump power of 20.3 W and pulse repetition frequency rate of 5 kHz, a maximum output power of 1.21 W is obtained, which is the highest output power for a 1.6 µm Raman laser. The corresponding optical-to-optical conversion efficiency is 6%; the pulse energy and peak power are 242 µJ and 8.96 kW, respectively.

Optoenergy storage and random walks assisted broadband amplification in Er3+-doped (Pb,La)(Zr,Ti)O3 disordered ceramics.

A broadband optical amplification was observed and investigated in Er3+-doped electrostrictive ceramics of lanthanum-modified lead zirconate titanate under a corona atmosphere. The ceramic structure change caused by UV light, electric field, and random walks originated from the diffusive process in intrinsically disordered materials may all contribute to the optical amplification and the associated energy storage. Discussion based on optical energy storage and diffusive equations was given to explain the findings. Those experiments performed made it possible to study random walks and optical amplification in transparent ceramics materials.

Influence of ceramic thickness and type on micromechanical properties of light-cured adhesive bonding agents.

OBJECTIVE: The aim of this study was to evaluate the micromechanical properties of different adhesive bonding agents when polymerized through ceramics. MATERIALS AND METHODS: Sixty sound extracted human third molars were selected and the crowns were sectioned perpendicular to the long axis in order to obtain dentin slices to be bonded with one of the following adhesives: Syntac/Heliobond (Ivoclar-Vivadent) or Adper-Scotchbond-1XT (3M-ESPE). The adhesives were cured by using a LED-unit (Bluephase®, Ivoclar Vivadent) with three different curing times (10 s, 20 s and 30 s) under two ceramics (IPS-e.max-Press, Ivoclar-Vivadent; IPS-Empress®CAD, Ivoclar-Vivadent) of different thicknesses (0 mm, 0.75 mm, 2 mm). Thirty groups were included, each containing 60 measurements. Micromechanical properties (Hardness, HV; indentation modulus, E; and creep, Cr) of the adhesives were measured with an automatic microhardness indenter (Fisherscope H100C, Germany). Data were statistically analyzed by using one-way ANOVA and Tukey's post-hoc test, as well as a multivariate analysis to test the influence of the study parameters (SPSS 18.0). RESULTS: Significant differences were observed between the micromechanical properties of the adhesives (p < 0.05). The ceramic type showed the highest effect on HV (Partial-eta squared (η(2)) = 0.109) of the tested adhesives, while E (η(2) = 0.275) and Cr (η(2) = 0.194) were stronger influenced by the adhesive type. Ceramic thickness showed no effect on the E and Cr of the adhesives. CONCLUSIONS: The adhesive bonding agents used in this study performed well by curing through different thicknesses of ceramics. The micromechanical properties of the adhesives were determined by the adhesive type and were less influenced by ceramic type and curing time.

Evaluation of experimental coating to improve the zirconia-veneering ceramic bond strength.

PURPOSE: To evaluate the shear bond strength (SBS) between zirconia and veneering ceramic following different surface treatments of zirconia. The efficacy of an experimental zirconia coating to improve the bond strength was also evaluated. MATERIALS AND METHODS: Zirconia strips were fabricated and were divided into four groups as per their surface treatment: polished (control), airborne-particle abrasion, laser irradiation, and application of the experimental coating. The surface roughness and the residual monoclinic content were evaluated before and after the respective surface treatments. A scanning electron microscope (SEM) analysis of the experimental surfaces was performed. All specimens were subjected to shear force in a universal testing machine. The SBS values were analyzed with one-way ANOVA followed by Bonferroni post hoc for groupwise comparisons. The fractured specimens were examined to observe the failure mode. RESULTS: The SBS (29.17 MPa) and roughness values (0.80) of the experimental coating group were the highest among the groups. The residual monoclinic content was minimal (0.32) when compared to the remaining test groups. SEM analysis revealed a homogenous surface well adhered to an undamaged zirconia base. The other test groups showed destruction of the zirconia surface. The analysis of failure following bond strength testing showed entirely cohesive failures in the veneering ceramic in all study groups. CONCLUSION: The experimental zirconia surface coating is a simple technique to increase the microroughness of the zirconia surface, and thereby improve the SBS to the veneering ceramic. It results in the least monoclinic content and produces no structural damage to the zirconia substructure.

Permittivity and performance of dielectric pads with sintered ceramic beads in MRI: early experiments and simulations at 3 T.

Passive dielectric materials have been used to improve aspects of MRI by affecting the distribution of radiofrequency electromagnetic fields. Recently, interest in such materials has increased with the number of high-field MRI sites. Here, we introduce a new material composed of sintered high-permittivity ceramic beads in deuterated water. This arrangement maintains the ability to create flexible pads for conforming to individual subjects. The properties of the material are measured and the performance of the material is compared to previously used materials in both simulation and experiment at 3 T. Results show that both permittivity of the beads and effect on signal-to-noise ratio and required transmit power in MRI are greater than those of materials consisting of ceramic powder in water. Importantly, use of beads results in both higher permittivity and lower conductivity than use of powder.

Tunable terahertz emission from the intrinsic Josephson junctions in acute isosceles triangular Bi2Sr2CaCu2O8+δ mesas.

In order to determine if the mesa geometry might affect the properties of the coherent terahertz (THz) radiation emitted from the intrinsic Josephson junctions in mesas constructed from single crystals of the high-temperature superconductor, Bi2Sr2CaCu2O8+δ, we studied triangular mesas. For equilateral triangular mesas, the observed emission was found to be limited to the single mesa TM(1,0) mode. However, tunable radiation over the range from 0.495 to 0.934 THz was found to arise from an acute isosceles triangular mesa. This 47% tunability is the widest yet observed from the outer current-voltage characteristic branch of such mesas of any geometry. Although the radiation at a few of the frequencies in the tunable range appear to have been enhanced by cavity resonances, most frequencies are far from such resonance frequencies, and can only be attributed to the ac-Josephson effect.

Swift carbon ion irradiated Nd:YAG ceramic optical waveguide amplifier.

A high-gain optical waveguide amplifier has been realized in a channel waveguide platform of Nd:YAG ceramic produced by swift carbon ion irradiation with metal masking. The waveguide is single mode at wavelength of 810 and 1064 nm, and with the enhanced fluorescence intensity at around 1064 nm due to the Nd(3+) ion emissions. In conjunction with the low propagation loss of the waveguide, about 26.3 dB/cm of the small signal gain at 1064 nm is achieved with an 18 ns pulse laser as the seeder under the 810-nm laser excitation. This work suggests the carbon ion irradiated Nd:YAG waveguides could serve as efficient integrated amplifiers for the signal amplification.

Study on the development of BSCCO superconducting device with a lever-type magnetic force measurement unit.

BiSrCaCuO superconductor with sliver oxide was prepared by thermal pyrolysis method to develop a superconductor device. The BiSrCaCuO superconductor with 2.0 wt% silver oxide showed the greatest suspension. The maximum induced voltage of the BiSrCaCuO superconductor with 2.0 wt.% of silver oxide formed by thermal pyrolysis method was about 3.95 mV at 2.0 x 10(-3) T. A lever-type magnetic force measurement unit quantitatively well determined the distance between the superconductor and toroidal magnet in which an attractive and a repulsive force due to suspension effect acted under a complicated magnetic field. It can be used for optimum designing a superconductor device.

Effects of different surface treatments on shear bond strength in two different ceramic systems.

The purpose of this study was to evaluate the influence of different surface treatments (sandblasting, acid etching, and laser irradiation) on the shear bond strength of lithium disilicate-based core (IPS Empress 2) and feldspathic ceramics (VITA VM 9). One hundred ceramic discs were divided into two groups of 50 discs each for two ceramic systems: IPS Empress 2 (group I) and VITA VM 9 (group II). Each of the two groups was further divided into five surface treatment groups (ten each) as follows: group SB, sandblasting with alumina particles (50 µm); group HF, 5 % hydrofluoric acid etching; group L, Er:YAG laser irradiation (distance, 1 mm; 500 mJ; 20 Hz; 10 W; manually, noncontact R14 handpiece); group SB-L, sandblasting + Er:YAG laser; and group HF-L, 5 % hydrofluoric acid + Er:YAG laser. Luting cement (Panavia 2.0) was bonded to the ceramic specimens using Teflon tubes. After 24 h of water storage, a shear bond strength test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed with a two-way analysis of variance (ANOVA) and Tukey's honestly significant difference tests (α = 0.05). The two-way ANOVA indicated that the shear bond strength was significantly affected by the surface treatment methods (p < 0.05), but there was no significant interaction between the ceramic systems. Group SB-L had the highest mean values for each ceramic system. Sandblasting, followed by Er:YAG laser irradiation, enhanced the bond strength, indicating its potential use as an alternative method. The atomic force microscopic evaluation revealed that group SB had the most distinct sharp peaks among the groups.

Laser-written waveguides in KTP for broadband Type II second harmonic generation.

Femto-second laser writing was used to fabricate waveguides in a z-cut KTP sample with losses below 0.8 dB/cm. They were used for efficient, broad bandwidth, Type II birefringent second harmonic generation to the green. The temperature and wavelength bandwidth were, 28 C ∙ cm and 0.85 nm ∙ cm, respectively.

Effect of laser remelting on the tribological performance of thermal barrier coatings.

Gas turbine's efficiency improves as operating temperature is increased. For this reason, metallic components used in turbine engines, for propulsion and power generation, are protected by thermal barrier coatings (TBC). Laser glazing has been used to enhance the oxidation and corrosion resistance of thermally sprayed TBC, but there is no information about the effect of this treatment on the tribological performance. ZrO2(CaO) top coat and NiAIMo bond coating were flame sprayed onto an AlSI 1045 carbon steel. The top coat was laser remelted and a densified ceramic layer was induced in the top surface of the ceramic coating. Both, the as sprayed and the laser remelted top coatings, were formed by cubic ZrO2 with some tetragonal precipitates. The grain size was reduced by the laser treatment. The mechanical properties and the local wear rate were evaluated by depth sensing indentation and scratch tests respectively. The nanoscale wear behaviour was always improved by the laser treatment.

The impact of Er,Cr:YSGG laser on the shear strength of the bond between dentin and ceramic is dependent on the adhesive material.

The bond joint between dentin and ceramic is a critical determinant in prosthodontic dentistry. The laser is an alternative to the diamond bur for preparing tooth cavities. However, the impact of lasers on the bond between the laser-irradiated dentin and the ceramic remains a matter of controversy. We determined the shear strength of bonds between ceramic blocks and human dentin discs prepared with either an Er,Cr:YSGG laser or a diamond bur. A total of 180 dentin discs were randomly assigned to four groups. Three groups of discs were prepared with the Er,Cr:YSGG laser irradiation (2 W, 30 Hz, 50% H(2)O, 70% air) and the fourth group was prepared with a diamond bur. In one of the laser groups the discs surfaces were also treated with phosphoric acid and in another with phosphoric acid and mechanical smoothing using a dental excavator. The ceramic blocks were bonded to the dentin discs with Syntac adhesive (together with Variolink II curing system), ExciTE adhesive (together with Variolink II curing system) or RelyX self-adhesive cement. The shear strength of the bond between ceramic and dentin was significantly higher following dentin surface treatment with the laser alone than following treatment with the diamond bur and Variolink II/Syntac (p = 0.021) but not significantly higher than following treatment with the diamond bur and Variolink II/ExciTE (p = 0.138) or RelyX (p = 0.150). A significant difference was not observed when the laser-treated dentin was conditioned with phosphoric acid and mechanical smoothing. These findings demonstrate that the bond between dentin and ceramic may be stronger after laser irradiation; however, the selection of the adhesive material is an additional factor that affects the bond strength.