Assessment of a chair-side argon-based non-thermal plasma treatment on the surface characteristics and integration of dental implants with textured surfaces Teixeira et al. surface
This study assessed the effects of a chair-side argon-based non-thermal plasma treatment on the surface characteristics and integration of dental implants. Scanning electron microscopy and optical interferometry showed the plasma treatment increased surface roughness and energy levels by removing adsorbed carbon species. X-ray photoelectron spectroscopy confirmed decreased carbon and increased levels of titanium and oxygen after plasma treatment. In a beagle dog model, implants treated with non-thermal plasma for 20 or 60 seconds had significantly higher removal torque values after 2 and 4 weeks of healing compared to untreated implants, indicating improved early biomechanical fixation.
This document describes a study that uses diagenetic modeling software to assess the relative timing of quartz cementation and brittle grain fracturing during burial compaction. The study examines samples from the Oligocene Frio Formation in the Gulf of Mexico Basin and the Cambrian Mount Simon Formation in the Illinois Basin. For the Mount Simon samples, the extent of grain fracturing correlates with reconstructed stress levels at the onset of cementation. However, for the Frio samples, the extent of fracturing does not correlate as well with reconstructed stress levels from basin modeling, suggesting overpressures developed at shallower depths than the models indicate. The degree of fracturing in sandstones provides observable evidence that can help understand complex pressure histories
Reliability and failure modes of internal conical dental implant connections ...Marcelo Januzzi Santos .`.
This study evaluated the reliability and failure modes of internal conical dental implant connections supporting maxillary incisor crowns. Forty-two implants from two different manufacturers were tested using step-stress accelerated life testing. Both implant systems had similar reliability and failure modes, with fractures occurring at the abutment-implant connection and screw neck region. The study found no significant differences in reliability or failure modes between the two internal conical implant connection systems tested.
This document summarizes a study on using geophysical methods like electrical resistivity surveys to identify groundwater prospective zones. The study was conducted in areas with thick alluvium geology. Vertical electrical sounding (VES) and 2D electrical resistivity tomography were used to map subsurface resistivity variations. Resistivity is dependent on factors like porosity, water content, and mineral composition. Aquifers were identified in saturated sand, sandy clay, and silt based on their resistivity values relative to surrounding materials. The study concluded electrical resistivity methods are well-suited for mapping aquifers, bedrock topography, and fractured zones to aid groundwater exploration programs.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
1) Vertical electrical sounding using Schlumberger array was conducted at 40 stations to determine subsurface layers and depth to bedrock at the Centre for Energy Research and Training in Zaria, Nigeria.
2) Resistivity values and thickness were derived for three predominant layers - topsoil (2-738 ohm-m thickening 1-3.9m), weathered basement (32-1735 ohm-m thickening 0.52-23m), and fresh basement bedrock (100-6036 ohm-m).
3) Results identified areas suitable for structures and boreholes, and recommended depth of sewage systems to avoid groundwater contamination based on the subsurface resistivity and thickness parameters.
The document summarizes a study investigating the controls on the formation of pulverized off-fault rocks (POFR) during earthquakes. Laboratory experiments were conducted using a split-Hopkinson pressure bar to dynamically compress Arkansas Novaculite rock specimens at varying strain rates. Preliminary results suggest that pulse shape and amplitude, which dictate stress, strain rate, and total strain, have a more fundamental control on the transition from localized fracture to pervasive fragmentation than any individual parameter. Specimen damage was characterized using various techniques and a portion of the energy budget was estimated to be consumed in creating new fracture surfaces. The results indicate between 1-40% of the energy budget can be attributed to fracture surface creation and inherent flaws exert an
O documento resume um seminário realizado pela Maçonaria Paulista para candidatos apoiados pelo seu Programa de Ação Política. O evento reuniu candidatos de diversos partidos e contou com depoimentos de maçons experientes em política. O objetivo é mobilizar os maçons do estado a apoiar candidatos comprometidos com a ética, para que trabalhem com dignidade caso eleitos.
This document describes a study that uses diagenetic modeling software to assess the relative timing of quartz cementation and brittle grain fracturing during burial compaction. The study examines samples from the Oligocene Frio Formation in the Gulf of Mexico Basin and the Cambrian Mount Simon Formation in the Illinois Basin. For the Mount Simon samples, the extent of grain fracturing correlates with reconstructed stress levels at the onset of cementation. However, for the Frio samples, the extent of fracturing does not correlate as well with reconstructed stress levels from basin modeling, suggesting overpressures developed at shallower depths than the models indicate. The degree of fracturing in sandstones provides observable evidence that can help understand complex pressure histories
Reliability and failure modes of internal conical dental implant connections ...Marcelo Januzzi Santos .`.
This study evaluated the reliability and failure modes of internal conical dental implant connections supporting maxillary incisor crowns. Forty-two implants from two different manufacturers were tested using step-stress accelerated life testing. Both implant systems had similar reliability and failure modes, with fractures occurring at the abutment-implant connection and screw neck region. The study found no significant differences in reliability or failure modes between the two internal conical implant connection systems tested.
This document summarizes a study on using geophysical methods like electrical resistivity surveys to identify groundwater prospective zones. The study was conducted in areas with thick alluvium geology. Vertical electrical sounding (VES) and 2D electrical resistivity tomography were used to map subsurface resistivity variations. Resistivity is dependent on factors like porosity, water content, and mineral composition. Aquifers were identified in saturated sand, sandy clay, and silt based on their resistivity values relative to surrounding materials. The study concluded electrical resistivity methods are well-suited for mapping aquifers, bedrock topography, and fractured zones to aid groundwater exploration programs.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
1) Vertical electrical sounding using Schlumberger array was conducted at 40 stations to determine subsurface layers and depth to bedrock at the Centre for Energy Research and Training in Zaria, Nigeria.
2) Resistivity values and thickness were derived for three predominant layers - topsoil (2-738 ohm-m thickening 1-3.9m), weathered basement (32-1735 ohm-m thickening 0.52-23m), and fresh basement bedrock (100-6036 ohm-m).
3) Results identified areas suitable for structures and boreholes, and recommended depth of sewage systems to avoid groundwater contamination based on the subsurface resistivity and thickness parameters.
The document summarizes a study investigating the controls on the formation of pulverized off-fault rocks (POFR) during earthquakes. Laboratory experiments were conducted using a split-Hopkinson pressure bar to dynamically compress Arkansas Novaculite rock specimens at varying strain rates. Preliminary results suggest that pulse shape and amplitude, which dictate stress, strain rate, and total strain, have a more fundamental control on the transition from localized fracture to pervasive fragmentation than any individual parameter. Specimen damage was characterized using various techniques and a portion of the energy budget was estimated to be consumed in creating new fracture surfaces. The results indicate between 1-40% of the energy budget can be attributed to fracture surface creation and inherent flaws exert an
O documento resume um seminário realizado pela Maçonaria Paulista para candidatos apoiados pelo seu Programa de Ação Política. O evento reuniu candidatos de diversos partidos e contou com depoimentos de maçons experientes em política. O objetivo é mobilizar os maçons do estado a apoiar candidatos comprometidos com a ética, para que trabalhem com dignidade caso eleitos.
Effect of implant–abutment connection design on reliability of crowns: regula...Marcelo Januzzi Santos .`.
This study evaluated the reliability and failure modes of regular and horizontally mismatched implant-abutment connections by subjecting them to step-stress accelerated life testing. The reliability was found to be not significantly different between the regular and mismatched groups. A Weibull analysis showed similar modulus and characteristic strength values between groups. The chief failure mode for both groups was fracture of the abutment screw. The results indicate that varying the implant diameter did not compromise the mechanical reliability of the connection.
O documento convida maçons dentistas e estudantes de odontologia de São Paulo a se juntarem ao recém-fundado Instituto Odontológico Maçônico Paulista. O instituto tem como objetivos defender a ética e excelência na odontologia, apoiar recém-formados, promover educação de qualidade e saúde bucal para a população de São Paulo. Os interessados são convidados a preencher cadastro no site do instituto para fortalecer a organização.
1) O documento é uma carta de recomendação do Capítulo Moacir Maurício Dantas No783 da Ordem DeMolay para apoiar o fechamento das comportas do Açude Público Santo Antonio devido ao racionamento de água.
2) A carta pede apoio da família maçônica e DeMolays para assinar um abaixo-assinado a ser enviado ao DNOCS sobre este assunto.
3) Também pede que o capítulo envie ofícios ao Capítulo Príncipe do Seridó pedindo aj
A White é uma clínica odontológica moderna e bem equipada que atende aos mais altos padrões de qualidade. Nosso objetivo é viabilizar o melhor tratamento dentário seja qual for a necessidade. A White oferece atendimento odontológico especializado em diversas áreas da odontologia: cirurgia, clareamento dental a laser, dentística, disfunção de articulação, endodontia, cirurgia parendodôntica, estética, halitose, laserterapia, implante, odontopediatria, periodontia e prótese.
O candidato envia seu currículo buscando uma vaga na empresa. Ele tem larga experiência desenvolvendo sistemas de gestão da produção e qualidade em empresas, incluindo um sistema certificado ISO 9000. Ele também tem experiência em treinamentos e em outras áreas como contabilidade.
fw1728_Final Year Project Report SubmissionFreddy White
The document is a final year project report submitted by Frederick A. O. White on April 27, 2015. It describes the design, development, and testing of an acoustic trapping device to trap live cells and microparticles. The device uses piezoelectric transducers to generate a standing wave acoustic field that successfully aligned human cells and 8 μm polymer beads while maintaining over 50% cell viability for up to two hours compared to controls. Computational analysis of particle distributions was used to study the quality and rate of alignment provided by the device.
This document summarizes a study that evaluated the bond strength of two root canal filling systems (ActiV GP and gutta-percha with AH Plus sealer) when used with different irrigation protocols. Forty single-rooted teeth were divided into four groups based on the final irrigation used: EDTA, EDTA followed by chlorhexidine, MTAD, or MTAD followed by chlorhexidine. Each group was further divided based on the filling system used. Horizontal sections were taken and subjected to push-out testing to measure bond strength. The results showed that EDTA followed by chlorhexidine yielded the highest bond strength for ActiV GP. MTAD and MTAD followed by chlorhexidine adversely affected the
This document describes an experimental study using centrifuge testing to evaluate the effectiveness of EPS (expanded polystyrene) geofoam as a seismic isolation method for earth retaining walls. Two centrifuge tests were performed on instrumented retaining wall models with and without EPS inclusions, subjected to cyclic shaking. Test results are compared to validate numerical analyses and better understand dynamic soil-structure interaction. The centrifuge testing allows modeling full-scale prototype behavior to study seismic isolation without issues of small-scale physical tests. Results provide insight into design and performance of retaining walls in earthquake regions.
This document describes a new device designed to measure dental implant stability using resonance frequency analysis. The device uses an electromagnetic actuator to deliver an impact force to the implant, triggering vibrations that are detected to determine the resonance frequency. In vitro and in vivo tests show the device provides measurements that highly correlate with a commercially available device. A clinical study using the new device found initial resonance frequency values above 10 kHz indicated implants were ready for immediate loading, while values from 4-10 kHz required more osseointegration time. The new device allows for minimum contact measurement of implant stability without additional attachment or disassembly steps.
This document is a resume for José R. Sánchez Pérez summarizing his education and experience. He received a Ph.D. in Materials Science from the University of Wisconsin-Madison, where he researched germanium thin films and nanomembranes. He has over 10 years of experience researching materials synthesis, characterization, and properties as a research assistant and associate at UW-Madison. His work focuses on strain effects in germanium and silicon nanomembranes for optoelectronic applications. He has also taught as a teaching assistant and supervised numerous undergraduate students.
This document describes the development of an in vivo rabbit ulnar loading model to study mechanical loading effects on bone. Strain levels during ulnar loading were characterized using strain gauges and finite element models. Rabbits underwent ulnar loading at varying strain levels, and periosteal bone formation was measured using histomorphometry. Loading at 3000-4500 microstrain produced a dose-dependent increase in periosteal bone formation compared to controls, with 4500 microstrain inducing the most robust response. Loading at 5250 microstrain induced woven bone formation. The rabbit ulnar loading model provides a translatable model for studying cortical bone adaptation and responses to pharmaceuticals.
Nanoparticles have various applications in modern separation science techniques. They can be used in liquid chromatography, gas chromatography, capillary electrophoresis, microchip electrophoresis, and ion chromatography. Nanoparticles are relatively easy to synthesize and functionalize, and have large surface area to volume ratios ideal for separations. Common nanoparticles used include gold nanoparticles, silica nanoparticles, and magnetic nanoparticles. They have been shown to improve separation efficiency, selectivity, and resolution compared to conventional separation methods. However, while successful in research, nanoparticle-based separations have not been widely adopted in industrial settings.
This study investigated the electron transfer mechanisms of Shewanella putrefaciens as a function of anode potential. It found that current generation and biofilm formation increased with more positive electrode potentials. Cyclic voltammetry showed that direct electron transfer was dominant over the potential range tested. Confocal laser scanning microscopy revealed that biofilm biomass coverage increased linearly with potential from 0 to +0.4V. This study provides new insights into how electrode potential influences electron transfer pathways and biofilm growth of S. putrefaciens.
This document summarizes a study that demonstrates the use of equally-sloped tomography (EST) to improve electron tomography reconstruction. EST acquires projection images at constant slope increments, allowing the use of a pseudo-polar fast Fourier transform to directly relate the projection and volume grids. The study applied EST to reconstruct frozen keyhole limpet hemocyanin molecules and a bacterial cell from tilt-series data. EST reconstructions exhibited higher contrast, less noise, clearer boundaries, and reduced missing wedge effects compared to other reconstruction methods. Surprisingly, EST reconstructions using only two-thirds of the original projections appeared to have the same resolution as full reconstructions using other methods, suggesting EST can reduce radiation dose requirements or allow higher resolutions.
The gravity field_and_interior_structure_of_enceladusSérgio Sacani
The gravity field and interior structure of Enceladus were determined using Doppler data from three Cassini flybys. There is a negative mass anomaly in the south polar region, largely compensated by a positive subsurface anomaly consistent with a regional subsurface sea at depths of 30-40 km extending to 50° south latitude. Enceladus deviates mildly from hydrostatic equilibrium, with estimated quadrupole coefficients indicating a differentiated body with a low-density core.
The gravity fieldandinteriorstructureofenceladusGOASA
The Cassini spacecraft measured Enceladus' gravity field during three flybys. The results indicate a negative mass anomaly over the south pole, likely compensated by a subsurface sea of water 30-40 km deep extending to 50° south latitude. Analysis of the gravity data suggests Enceladus has differentiated into a low-density core with a moment of inertia around 0.335 times its mass times the square of its radius, consistent with the presence of liquid water beneath the surface. The endogenic heat output and gravity data are best explained by models involving tidal heating of Enceladus' interior through past or current orbital resonances.
Statistical analysis of electrodeposited in2 s3 films techconnect conferenceArkansas State University
In2S3 has received attention as an alternative to CdS as the buffer layer in heterojunction solar cells. Although having a bandgap of 2.0 eV relative to 2.5 eV for CdS, the lower toxicity and environmental impact of indium relative to cadmium, and significant photosensitivity, compel ongoing research [1]. Indium sulfide thin films were deposited onto molybdenum-coated glass (SiO2) substrates by electrodeposition from organic baths (ethylene glycol-based) containing indium chloride (InCl3), sodium chloride (NaCl), and sodium thiosulfate (Na2S2O3.5H2O), the latter used as an additional sulfur source along with elemental sulfur (S). The Taguchi method was used to optimize the deposition paramters so as to minimize non-uniformity, cracks, and improper stoichiometry. The measured performance characteristics (molar ratio (In:S) and crack density) for all of the In2S3 films were calculated to analyze the effect of each deposition factor (deposition voltage, deposition temperature, composition of solution, and deposition time) involved in the electrodeposition process by calculating the sensitivity (signal to noise, S/N, ratios).
Application of stereolithography in mandibular reconstruction following rese...Quách Bảo Toàn
A 32-year-old woman presented with swelling on the right side of her mandible. Imaging showed a multilocular lesion involving the angle, ramus, and part of the right body. Biopsy confirmed ameloblastoma. The patient underwent partial resection of the mandible with a titanium plate reconstruction planned using stereolithography. Stereolithography was used to create a precise 3D model of the resection area from CT scans for preoperative planning and plate fitting. The surgery and reconstruction were performed using the presurgically planned and fitted plate, demonstrating the value of stereolithography for complex mandibular reconstruction planning and implementation.
1) Aligned silver nanorod (AgNR) array films were fabricated by oblique thermal evaporation at various substrate temperatures ranging from 10 to 100°C. 2) Scanning electron microscopy showed that increasing the substrate temperature led to increases in nanorod diameter but decreases in length, density, and bundling between nanorods. 3) A critical temperature of around 90°C was found, above which the nanorod array structure disappeared and a flat film formed due to increased coalescence between nuclei.
Variation of dose distribution with depth and incident energy using EGSnrc Mo...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
The document discusses nanofibers and their production via electrospinning. It defines nanofibers as fibers with diameters less than 1000 nm and notes their small size compared to human hair. The document then explains the electrospinning process, where a high voltage draws thin fibers from a liquid source. Key aspects reviewed include the Taylor cone formation, bending instability that reduces fiber diameters, and parameters that impact electrospinning. Finally, it outlines early nanofiber production at UPLB involving various polymers like PCL, PVC and PLGA.
Effect of implant–abutment connection design on reliability of crowns: regula...Marcelo Januzzi Santos .`.
This study evaluated the reliability and failure modes of regular and horizontally mismatched implant-abutment connections by subjecting them to step-stress accelerated life testing. The reliability was found to be not significantly different between the regular and mismatched groups. A Weibull analysis showed similar modulus and characteristic strength values between groups. The chief failure mode for both groups was fracture of the abutment screw. The results indicate that varying the implant diameter did not compromise the mechanical reliability of the connection.
O documento convida maçons dentistas e estudantes de odontologia de São Paulo a se juntarem ao recém-fundado Instituto Odontológico Maçônico Paulista. O instituto tem como objetivos defender a ética e excelência na odontologia, apoiar recém-formados, promover educação de qualidade e saúde bucal para a população de São Paulo. Os interessados são convidados a preencher cadastro no site do instituto para fortalecer a organização.
1) O documento é uma carta de recomendação do Capítulo Moacir Maurício Dantas No783 da Ordem DeMolay para apoiar o fechamento das comportas do Açude Público Santo Antonio devido ao racionamento de água.
2) A carta pede apoio da família maçônica e DeMolays para assinar um abaixo-assinado a ser enviado ao DNOCS sobre este assunto.
3) Também pede que o capítulo envie ofícios ao Capítulo Príncipe do Seridó pedindo aj
A White é uma clínica odontológica moderna e bem equipada que atende aos mais altos padrões de qualidade. Nosso objetivo é viabilizar o melhor tratamento dentário seja qual for a necessidade. A White oferece atendimento odontológico especializado em diversas áreas da odontologia: cirurgia, clareamento dental a laser, dentística, disfunção de articulação, endodontia, cirurgia parendodôntica, estética, halitose, laserterapia, implante, odontopediatria, periodontia e prótese.
O candidato envia seu currículo buscando uma vaga na empresa. Ele tem larga experiência desenvolvendo sistemas de gestão da produção e qualidade em empresas, incluindo um sistema certificado ISO 9000. Ele também tem experiência em treinamentos e em outras áreas como contabilidade.
Similar to Assessment of a chair-side argon-based non-thermal plasma treatment on the surface characteristics and integration of dental implants with textured surfaces Teixeira et al. surface
fw1728_Final Year Project Report SubmissionFreddy White
The document is a final year project report submitted by Frederick A. O. White on April 27, 2015. It describes the design, development, and testing of an acoustic trapping device to trap live cells and microparticles. The device uses piezoelectric transducers to generate a standing wave acoustic field that successfully aligned human cells and 8 μm polymer beads while maintaining over 50% cell viability for up to two hours compared to controls. Computational analysis of particle distributions was used to study the quality and rate of alignment provided by the device.
This document summarizes a study that evaluated the bond strength of two root canal filling systems (ActiV GP and gutta-percha with AH Plus sealer) when used with different irrigation protocols. Forty single-rooted teeth were divided into four groups based on the final irrigation used: EDTA, EDTA followed by chlorhexidine, MTAD, or MTAD followed by chlorhexidine. Each group was further divided based on the filling system used. Horizontal sections were taken and subjected to push-out testing to measure bond strength. The results showed that EDTA followed by chlorhexidine yielded the highest bond strength for ActiV GP. MTAD and MTAD followed by chlorhexidine adversely affected the
This document describes an experimental study using centrifuge testing to evaluate the effectiveness of EPS (expanded polystyrene) geofoam as a seismic isolation method for earth retaining walls. Two centrifuge tests were performed on instrumented retaining wall models with and without EPS inclusions, subjected to cyclic shaking. Test results are compared to validate numerical analyses and better understand dynamic soil-structure interaction. The centrifuge testing allows modeling full-scale prototype behavior to study seismic isolation without issues of small-scale physical tests. Results provide insight into design and performance of retaining walls in earthquake regions.
This document describes a new device designed to measure dental implant stability using resonance frequency analysis. The device uses an electromagnetic actuator to deliver an impact force to the implant, triggering vibrations that are detected to determine the resonance frequency. In vitro and in vivo tests show the device provides measurements that highly correlate with a commercially available device. A clinical study using the new device found initial resonance frequency values above 10 kHz indicated implants were ready for immediate loading, while values from 4-10 kHz required more osseointegration time. The new device allows for minimum contact measurement of implant stability without additional attachment or disassembly steps.
This document is a resume for José R. Sánchez Pérez summarizing his education and experience. He received a Ph.D. in Materials Science from the University of Wisconsin-Madison, where he researched germanium thin films and nanomembranes. He has over 10 years of experience researching materials synthesis, characterization, and properties as a research assistant and associate at UW-Madison. His work focuses on strain effects in germanium and silicon nanomembranes for optoelectronic applications. He has also taught as a teaching assistant and supervised numerous undergraduate students.
This document describes the development of an in vivo rabbit ulnar loading model to study mechanical loading effects on bone. Strain levels during ulnar loading were characterized using strain gauges and finite element models. Rabbits underwent ulnar loading at varying strain levels, and periosteal bone formation was measured using histomorphometry. Loading at 3000-4500 microstrain produced a dose-dependent increase in periosteal bone formation compared to controls, with 4500 microstrain inducing the most robust response. Loading at 5250 microstrain induced woven bone formation. The rabbit ulnar loading model provides a translatable model for studying cortical bone adaptation and responses to pharmaceuticals.
Nanoparticles have various applications in modern separation science techniques. They can be used in liquid chromatography, gas chromatography, capillary electrophoresis, microchip electrophoresis, and ion chromatography. Nanoparticles are relatively easy to synthesize and functionalize, and have large surface area to volume ratios ideal for separations. Common nanoparticles used include gold nanoparticles, silica nanoparticles, and magnetic nanoparticles. They have been shown to improve separation efficiency, selectivity, and resolution compared to conventional separation methods. However, while successful in research, nanoparticle-based separations have not been widely adopted in industrial settings.
This study investigated the electron transfer mechanisms of Shewanella putrefaciens as a function of anode potential. It found that current generation and biofilm formation increased with more positive electrode potentials. Cyclic voltammetry showed that direct electron transfer was dominant over the potential range tested. Confocal laser scanning microscopy revealed that biofilm biomass coverage increased linearly with potential from 0 to +0.4V. This study provides new insights into how electrode potential influences electron transfer pathways and biofilm growth of S. putrefaciens.
This document summarizes a study that demonstrates the use of equally-sloped tomography (EST) to improve electron tomography reconstruction. EST acquires projection images at constant slope increments, allowing the use of a pseudo-polar fast Fourier transform to directly relate the projection and volume grids. The study applied EST to reconstruct frozen keyhole limpet hemocyanin molecules and a bacterial cell from tilt-series data. EST reconstructions exhibited higher contrast, less noise, clearer boundaries, and reduced missing wedge effects compared to other reconstruction methods. Surprisingly, EST reconstructions using only two-thirds of the original projections appeared to have the same resolution as full reconstructions using other methods, suggesting EST can reduce radiation dose requirements or allow higher resolutions.
The gravity field_and_interior_structure_of_enceladusSérgio Sacani
The gravity field and interior structure of Enceladus were determined using Doppler data from three Cassini flybys. There is a negative mass anomaly in the south polar region, largely compensated by a positive subsurface anomaly consistent with a regional subsurface sea at depths of 30-40 km extending to 50° south latitude. Enceladus deviates mildly from hydrostatic equilibrium, with estimated quadrupole coefficients indicating a differentiated body with a low-density core.
The gravity fieldandinteriorstructureofenceladusGOASA
The Cassini spacecraft measured Enceladus' gravity field during three flybys. The results indicate a negative mass anomaly over the south pole, likely compensated by a subsurface sea of water 30-40 km deep extending to 50° south latitude. Analysis of the gravity data suggests Enceladus has differentiated into a low-density core with a moment of inertia around 0.335 times its mass times the square of its radius, consistent with the presence of liquid water beneath the surface. The endogenic heat output and gravity data are best explained by models involving tidal heating of Enceladus' interior through past or current orbital resonances.
Statistical analysis of electrodeposited in2 s3 films techconnect conferenceArkansas State University
In2S3 has received attention as an alternative to CdS as the buffer layer in heterojunction solar cells. Although having a bandgap of 2.0 eV relative to 2.5 eV for CdS, the lower toxicity and environmental impact of indium relative to cadmium, and significant photosensitivity, compel ongoing research [1]. Indium sulfide thin films were deposited onto molybdenum-coated glass (SiO2) substrates by electrodeposition from organic baths (ethylene glycol-based) containing indium chloride (InCl3), sodium chloride (NaCl), and sodium thiosulfate (Na2S2O3.5H2O), the latter used as an additional sulfur source along with elemental sulfur (S). The Taguchi method was used to optimize the deposition paramters so as to minimize non-uniformity, cracks, and improper stoichiometry. The measured performance characteristics (molar ratio (In:S) and crack density) for all of the In2S3 films were calculated to analyze the effect of each deposition factor (deposition voltage, deposition temperature, composition of solution, and deposition time) involved in the electrodeposition process by calculating the sensitivity (signal to noise, S/N, ratios).
Application of stereolithography in mandibular reconstruction following rese...Quách Bảo Toàn
A 32-year-old woman presented with swelling on the right side of her mandible. Imaging showed a multilocular lesion involving the angle, ramus, and part of the right body. Biopsy confirmed ameloblastoma. The patient underwent partial resection of the mandible with a titanium plate reconstruction planned using stereolithography. Stereolithography was used to create a precise 3D model of the resection area from CT scans for preoperative planning and plate fitting. The surgery and reconstruction were performed using the presurgically planned and fitted plate, demonstrating the value of stereolithography for complex mandibular reconstruction planning and implementation.
1) Aligned silver nanorod (AgNR) array films were fabricated by oblique thermal evaporation at various substrate temperatures ranging from 10 to 100°C. 2) Scanning electron microscopy showed that increasing the substrate temperature led to increases in nanorod diameter but decreases in length, density, and bundling between nanorods. 3) A critical temperature of around 90°C was found, above which the nanorod array structure disappeared and a flat film formed due to increased coalescence between nuclei.
Variation of dose distribution with depth and incident energy using EGSnrc Mo...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
The document discusses nanofibers and their production via electrospinning. It defines nanofibers as fibers with diameters less than 1000 nm and notes their small size compared to human hair. The document then explains the electrospinning process, where a high voltage draws thin fibers from a liquid source. Key aspects reviewed include the Taylor cone formation, bending instability that reduces fiber diameters, and parameters that impact electrospinning. Finally, it outlines early nanofiber production at UPLB involving various polymers like PCL, PVC and PLGA.
Synthesis and Characterization of Novel Nanomaterials for SERS Biomedical/Env...Necla YÜCEL
In this study, a simple green method was employed to synthesize functionalized silver nanoparticles (Ag NPs) as surface-enhanced Raman scattering (SERS) substrate for detection of dopamine (DA). In this method, polyethylene glycol (PEG) was functionalized on silver nanoparticles to prepare the uniform and controlled size of nanoparticles (NPs). The optical and structural properties of functionalized nanoparticles were characterized. The Raman spectra of the prepared PEG-Ag SERS substrate clearly indicated an enhancement in the SERS signal of dopamine. The developed functionalized SERS substrate can be potentially used as a sensitive SERS substrate for detection of various neurotransmitters for biomedical application.
The study of intermolecular interactions at interfaces is essential for a number of applications, in addition
to the understanding of mechanisms involved in sensing and biosensing with liquid samples. There are,
however, only a few methods to probe such interfacial phenomena, one of which is the atomic force
spectroscopy (AFS) where the force between an atomic force microscope tip and the sample surface is
measured. In this study, we used AFS to estimate adhesion forces for a nanostructured film of poly(oethoxyaniline)
(POEA) doped with various acids, in measurements performed in air. The adhesion force
was lower for POEA doped with inorganic acids, such as HCl and H2SO4, than with organic acids, because
the counterions were screened by the ethoxy groups. Significantly, the morphology of POEA both in the
film and in solution depends on the doping acid. Using small-angle X-ray scattering (SAXS) we observed
that POEA dissolved in amixture of dimethyl acetamide exhibits a more extended coil-like conformation,
with smaller radius of gyration, than for POEA in water, as in the latter POEA solubility is lower. In AFS
measurements in a liquid cell, the force curves for a POEA layer displayed an attractive region for pH 5
due to van der Waals interactions, with no contribution from a double-layer since POEA was dedoped. In
contrast, for pH 3, POEA was doped and the repulsive double-layer force dominated. With AFS one is
therefore able to correlate molecular-level interactions with doping and morphology of semiconducting
polymers.
Geo Environmental Investigation of Abuad Dumpsite, Southwestern NigeriaIJERA Editor
Geoenvironmental study of ABUAD female dumpsite was conducted to investigate the suitability of its location
and potential impact on groundwater in the environment. Profiling and Vertical electrical sounding methods
were employed using Dipole - Dipole and Schlumberger configuration respectively. Five points were sounded
and one profile was occupied. Three heterogeneous subsurface lithologic units were established namely; lateritic
topsoil, clayey-sand, and, fresh basement. The curve types are simple H and HA. The topsoil and clayey-sand
materials are characterized with relatively low resistivity values while the fresh basement materials are
characterized with high resistivity values. The average resistivity and thickness values for the topsoil are
280.0Ωm and.2.3m respectively. Clayey-sand was encountered in all the locations with average resistivity and
thickness values of 32.0Ωm and 7.3m respectively. Basement is relatively shallow in the study area, it was
encountered in all the locations with an average resistivity and depth values to the top of basement of 674Ωm,
and 9.6m respectively. Overburden materials are relatively thin within the area with an average resistivity and
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Assessment of a chair-side argon-based non-thermal plasma treatment on the surface characteristics and integration of dental implants with textured surfaces Teixeira et al. surface
1. J O U R N A L O F T H E M E C H A N I C A L B E H AV I O R O F B I O M E D I C A L M AT E R I A L S 9 (2012) 45–49
Available online at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/jmbbm
Short communication
Assessment of a chair-side argon-based non-thermal plasma
treatment on the surface characteristics and integration of
dental implants with textured surfaces
Hellen S. Teixeira a,⇤ , Charles Marin b , Lukasz Witek a , Amilcar Freitas Jr. a ,
Nelson R.F. Silva c , Thomas Lilin d , Nick Tovar a , Malvin N. Janal e , Paulo G. Coelho a
a Department of Biomaterials and Biomimetics, New York University, New York, NY, USA
b Department of Dentistry, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
c Department of Prosthodontics, New York University, New York, NY, USA
d École Nationale Vétérinaire d’Alfort, Maisons-Alfort, Val-de-Marne, France
e Department of Epidemiology and Health Promotion, New York University, New York, NY, USA
A R T I C L E I N F O A B S T R A C T
Article history: The biomechanical effects of a non-thermal plasma (NTP) treatment, suitable for use in a
Received 31 May 2011 dental office, on the surface character and integration of a textured dental implant surface
Received in revised form in a beagle dog model were evaluated. The experiment compared a control treatment,
9 January 2012 which presented an alumina-blasted/acid-etched (AB/AE) surface, to two experimental
Accepted 14 January 2012 treatments, in which the same AB/AE surface also received NTP treatment for a period
Published online 31 January 2012 of 20 or 60 s per implant quadrant (PLASMA 200 and PLASMA 600 groups, respectively).
The surface of each specimen was characterized by electron microscopy and optical
Keywords: interferometry, and surface energy and surface chemistry were determined prior to and
Implant surface treatment after plasma treatment. Two implants of each type were then placed at six bilateral
Argon plasma locations in 6 dogs, and allowed to heal for 2 or 4 weeks. Following sacrifice, removal
Surface modification torque was evaluated as a function of animal, implant surface and time in vivo in a
Osseointegration mixed model ANOVA. Compared to the CONTROL group, PLASMA 200 and 600 groups
in vivo presented substantially higher surface energy levels, lower amounts of adsorbed C species
and significantly higher torque levels (p = .001). Result indicated that the NTP treatment
increased the surface energy and the biomechanical fixation of textured-surface dental
implants at early times in vivo.
c 2012 Elsevier Ltd. All rights reserved.
1. Introduction events that leads to bone healing and intimate interaction
with the device (Jimbo et al., 2007). Several reviews (Coelho
The rationale for surface modification focuses on implant et al., 2009; Dohan Ehrenfest et al., 2010) lead to a gen-
interaction with biofluids positively altering the cascade of eral consensus that both rough surfaces (over smooth turned
⇤ Correspondence to: New York University College of Dentistry, 345 E 24th Street, room 813a, New York, NY 10010, USA. Tel.: +1 212 998
9214; fax: +1 212 998 9214.
E-mail address: hst228@nyu.edu (H.S. Teixeira).
1751-6161/$ - see front matter c 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jmbbm.2012.01.012
2. 46 J O U R N A L O F T H E M E C H A N I C A L B E H AV I O R O F B I O M E D I C A L M AT E R I A L S 9 (2012) 45–49
surfaces) and surface chemistry (Ca–P based coatings over average high deviation), Sq (root mean square), Sds (density of
non-coated surfaces) favor the early host-to-implant re- summits), and Sdr (developed surface ratio) parameters were
sponse (Albrektsson and Wennerberg, 2004a,b; Coelho et al., determined. A filter size of 250 µm ⇥ 250 µm was utilized.
2009). Surface energy (SE) was determined using the Owens–
However, in most cases, combinations of texture and Wendt–Rabel–Kaelble (OWRK) method (Owens and Wendt,
chemistry known to hasten osseointegration are proprietary 1969). Briefly, 500 µl droplets of distilled water, ethylene
processes and not available for the dental community. An glycol, and diiodomethane were deposited on the surface
economically viable, chair side, operator (dental surgeon) of each implant with a micro-pipette (OCA 30, Data Physics
controlled surface treatment that enhances the host response Instruments GmbH, Filderstadt, Germany). Images were
to any implant surface would provide better treatment to captured and analyzed using SCA30 software (version 3.4.6
more patients. build 79). The relationship between the contact angle and SE
While prior attempts to modify surface characteristics D P D
was calculated as L = L + L , where L is the SE, L is the
with thermal or radio-frequency plasma devices were disperse component and L P is the polar component.
successful, they operated either at high temperatures or Surface specific chemical assessment was performed by
under low pressures. As well, because the equipment was X-ray photoelectron spectroscopy (XPS). The implants (n = 3,
expensive and unreliable, these processes fell from favor each group) were inserted in a vacuum transfer chamber and
(Aronsson et al., 1997; Baier, 1986, 1987; Baier and Meyer, degassed to 10 7 torr. The samples were then transferred
1988). By contrast, non-thermal plasmas (NTPs) deploy under vacuum to a Kratos Axis 165 multitechnique XPS
most of their energy to drive “high-temperature” chemistry, spectrometer (Kratos Analytical Inc., Chestnut Ridge, NY,
allowing surface activation/modification while operating USA). Spectra were obtained using a 165 mm mean radius
at room temperatures (Barker, 2005). Unlike previous concentric hemispherical analyzer operated at constant pass
radiofrequency technology that required low pressures (Liu
energy of 160 eV for survey and 80 eV for high resolution
et al., in press), recent innovation, has scaled microplasma
scans. The take off angle was 90 and a spot size of 150 µm ⇥
NTP generators to dimensions that are small enough to
150 µm was used. The implant surfaces were evaluated at
allow safe and portable operation in the clinical setting at
various locations.
atmospheric pressure, while providing sufficient energy to
The in vivo study included 6 adult male beagle dogs,
generate meaningful increases in surface energy.
approximately 1.5 years of age. The experimental protocol
The incorporation of reactive species and surface cleaning
received the approval of the École Nationale Vétérinaire
may result in increased levels of surface reactivity and energy
d’Alfort (Maisons-Alfort, Val-de-Marne, France).
that could improve the integration of commercially available
All surgical procedures were performed under gen-
implant surfaces. The objective of the present investigation
eral anesthesia. The pre-anesthetic procedure comprised
was to evaluate the biomechanical effects of an Ar-based NTP
an intra-muscular (IM) administration of atropine sulfate
treatment, suitable for use in the dental office and applied
(0.044 mg/kg) and xylazine chlorate (8 mg/kg). General anes-
immediately prior to implantation, on the surface character
thesia was then obtained following an IM injection of
and integration of a dental implant with a textured surface,
ketamine chlorate (15 mg/kg). Following hair shaving, skin
in a beagle dog model.
exposure, and antiseptic cleaning with iodine solution at the
surgical and surrounding area, a 5 cm incision at the skin level
was performed. Then, a flap was reflected and the radius dia-
2. Materials and methods
physis exposed.
This study utilized screw root form endosseous grade IV The surgical region was the center of the radius diaphysis,
titanium alloy implants of 3.8 mm in diameter by 8.5 mm in where three implants (one of each treatment) were placed
length. The implants provided by the manufacturer presented into each limb. The right and left limbs received implants
an alumina-blasted and acid-etched (AB/AE) surface (Duo that remained for periods of 2 and 4 weeks in vivo (two
System, Signo Vinces, Brazil). distinct surgical procedures were performed), respectively.
The control treatment used implant specimens as- The implants were alternately placed from proximal to distal
supplied, while two experimental groups used these same at distances of 1 cm from each other along the central region
implants and treated them with either 20 or 60 s of non- of the bone, and the start surface site (CONTROL, PLASMA
thermal plasma (NTP) per quadrant (PLASMA 200 , PLASMA 200 , AND PLASMA 600 ) was alternated between animals. The
600 ). The plasma was applied with a KinPenTM device (INP- implant distribution resulted in an equal number of implants
Greifswald, Germany). The plasma treatment was applied for the 2 and 4 weeks comparison for both surfaces.
immediately prior to any characterization assessment and Drilling started with a 2 mm diameter pilot drill at
again prior to implantation in the in vivo component of this 1200 rpm and was followed with burs of 2.5 mm and 3.2 mm
study. at 800 rpm, all under saline irrigation. The implants were then
SEM (Philips XL 30, Eindhoven, The Netherlands) was placed into the drilled sites by means of a torque wrench.
performed at various magnifications under an acceleration Standard layered suture techniques were utilized for wound
voltage of 15 kV. Surface roughness was evaluated in three closure (4-0 vicryl—internal layers, 4-0 nylon—the skin).
control implants by optical interferometry (IFM) (Phase View Post-surgical medication included antibiotics (penicillin,
2.5, Palaiseau, France) at the flat region of the implant cutting 20.000 UI/kg) and analgesics (ketoprophen, 1 ml/5 kg) for
edges (three measurements per implant). Sa (arithmetic a period of 48 h post-operatively. The euthanasia was
3. J O U R N A L O F T H E M E C H A N I C A L B E H AV I O R O F B I O M E D I C A L M AT E R I A L S 9 (2012) 45–49 47
performed by anesthesia overdose 4 weeks and 2 weeks after 4. Discussion
the first and second surgical procedures, respectively.
At necropsy, the limbs were retrieved by sharp dissection; The plasma state is often referred to as the 4th state of
the soft tissue was removed by surgical blades. For the matter, characterized by the presence of positive (sometime
torque testing, the radius was adapted to an electronic also negative) ions and negatively charged electrons in a
torque machine equipped with a 200 Ncm torque load cell neutral background gas (Lieberman and Lichtenberg, 1994).
(Test Resources, Minneapolis, MN, USA). Custom machine Plasmas are created by supplying energy (often electrical
tooling was adapted to each implant internal connection and energy) to a volume containing gases, so that a certain
the bone block was carefully positioned to avoid specimen fraction of free electrons and ions are generated from the
misalignment during testing. The implants were torqued in neutral constituents. In technical plasma devices, the plasma
the counter clockwise direction at a rate of ⇠0.196 rad/min, is generally generated using electrical discharges (Lieberman
and a torque versus displacement curve were recorded for and Lichtenberg, 1994). To date, implant surfaces have been
each specimen. both cleaned and/or sterilized by radiofrequency plasma
Preliminary evaluation showed heterogeneous variances devices or plasma coated with bioactive ceramics with high
in the torque measure between groups; the control treatment temperature plasma sources (Coelho and Lemons, 2009).
at 4 weeks in vivo time was notably (more, less) variable Unlike previous plasma technology, where specialized
than the other conditions. Variances were homogenized by equipment environment was required, NTPs can drive
transforming the data to ranks. A mixed model ANOVA was “high-temperature” chemistry at ambient temperatures at
then used to compare rank torque by time and treatment. atmospheric pressure (Barker, 2005). Thus, depending on
Statistical significance was set to ↵ = 0.05. Thus, while
plasma set up and chemistry, a wide range of implant
the raw torque data are presented, in order to maximize
surface alterations are achievable and may be utilized at
interpretation, analysis considered only the ranked data,
the operating room immediately prior to implant placement
which better satisfied the assumptions of this statistical
under atmospheric conditions (these units may be fabricated
model.
in portable sizes). The present study characterized surface
energy and chemistry in AB/AE surfaces and its effect on
biomechanical fixation at early implantation times in vivo.
3. Results
The SEM and IFM assessment showed that the roughness
of these implant surfaces were similar to that of several other
The scanning electron micrographs of the implant surfaces
commercially available products (Coelho et al., 2009). The
revealed a textured microstructure (Fig. 1(a)). There were
surface energy assessment prior and after NTP application
no particles evident from the alumina-blasting procedure.
An example of the three-dimensional reconstruction of the showed a substantial increase in surface energy (in both
surface is presented in Fig. 1(b) along with the Sa, Sq, polar and disperse components). The XPS results showed that
Sds, and Sdr roughness parameters. The surface energy (SE) surface elemental chemistry was modified by the 20 s and
was substantially greater than the CONTROL group in both 60 s Ar-based NTP treatment, and that this change resulted in
PLASMA 200 and PLASMA 600 groups (Fig. 1(c)). This general higher degree of exposure of the surface chemical elements
increase arose from both polar and disperses components. mainly at the expense of the removal of adsorbed C species
The surface chemistry assessment of the CONTROL surface (Coelho and Lemons, 2009). The higher degree of surface
showed 36% C, 44% O, 16% Ti, and 2% N, and traces of Si and energy observed for the CaP-Plasma is likely related to the
P. Relative to the CONTROL group, both plasma treated groups removal of the adsorbed C species from the surface (Baier,
evidence a decreased level of C and increased levels of Ti and 1986, 1987; Baier and Meyer, 1988).
O (Fig. 1(d)). High-resolution spectral evaluation showed that The increase in surface energy and differences in surface
carbon was present primarily as a hydrocarbon (C–C, C–H) on chemistry where plasma treated groups showed lower
all surfaces. amounts of adsorbed species relative to the CONTROL
The surgical procedures and follow-up demonstrated no group likely accounted for the significantly higher levels
complications or other clinical concerns, and no implant of biomechanical fixation observed at early implantation
was excluded due to clinical instability (determined after times in the in vivo laboratory model. The lack of difference
euthanization). The raw torque values in each group and time between both plasma treated groups was possible due to
in vivo (mean ± SD) are presented in Fig. 2. In general, there the remarkably similar SE and XPS results, depicting that
appears to be substantially increased interfacial strength in exposure times as short as 20 s is sufficient to hasten the early
each of the two plasma conditions and somewhat greater host-to-implant response, as surface energy and wettability
strength in 4 than 2 week implantations. The ANOVA of of biomaterials are properties that are known to enhance
ranked data showed an effect of implant surface treatment adhesion, proliferation, and mineralization of osteoblasts
(p = 0.001), but not time in vivo (p = 0.47), or the interaction (Lai et al., 2010; Lim et al., 2004, 2008; Sista et al., 2011).
of these factors (p = 0.37). The mean torque rank and 95% For instance, Buser et al. (2004) have demonstrated that
confidence intervals are presented in Fig. 3 as a function increasing the surface energy of a grit-blasted implant surface
of surface treatment and time in vivo, where significantly by means of proprietary cleaning and storage in isotonic
higher torque was detected for both PLASMA 200 and PLASMA solution hastened osseointegration of dental implants at
600 relative to the CONTROL. While a slight increase in torque early implantation times relative to controls presenting the
was detected from 2 to 4 weeks in vivo, this difference was same surface roughness profile but lower surface energy
not significant. levels (Buser et al., 2004). In contrast to NTP treatment, where
4. 48 J O U R N A L O F T H E M E C H A N I C A L B E H AV I O R O F B I O M E D I C A L M AT E R I A L S 9 (2012) 45–49
A B
C D
Fig. 1 – (a) Scanning electron micrograph and (b) IFM three-dimensional reconstruction of the AB/AE surface used in the
present study. (c) Surface energy assessment showed that increases in both the polar and disperse components of both
plasma treated surfaces accounted for the overall higher surface energy values of those groups relative to the CONTROL
group. (d) The surface chemistry assessment of the CONTROL surface showed 36% C, 44% O, 16% Ti, and 2% N, and traces of
Si and P. Remarkably similar surface chemistry profiles were obtained for both plasma treated groups, where a decreased
amount of C along with increases in Ti and O contents were observed compared to the CONTROL group.
Fig. 3 – Rank torque data (mean ± 95% confidence interval)
as a function of surface treatment and time in vivo. A like
number of asterisks depict statistically homogeneous
groups.
Fig. 2 – Raw torque data (mean ± standard error) for all 5. Conclusion
groups at both implantation times in vivo.
Treatment of dental implants with textured surfaces with
room temperature plasma and delivered by a practitioner-
any given implant surface may be treated immediately prior
to placement, the implant is stored in isotonic solution until friendly device, produced substantial improvements in
immediately prior to placement so that the gain in surface biomechanical fixation at early implantation times.
energy is maintained.
Considering the favorable effects that have been observed
when NTPs were used in biomedical applications (Aronsson
Acknowledgment
et al., 1997), the utilization of low temperature, atmospheric
pressure Ar-plasma on surface alterations may be a promising
technique to improve the efficiency of implant osseointegra- The present study was partially supported by Signo Vinces,
tion and biomechanical fixation. Brazil.
5. J O U R N A L O F T H E M E C H A N I C A L B E H AV I O R O F B I O M E D I C A L M AT E R I A L S 9 (2012) 45–49 49
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