Nanoscale texture on glass and titanium substrates by physical vapor deposition process

The aim of the paper is to give a feasibility study on the material deposition of Nanoscale textured morphology of titanium and titanium oxide layers on titanium and glass substrates. As a recent development in nanoscale deposition, Physical Vapor Deposition (PVD) based DC magnetron sputtering has been the choice for the deposition process. The nanoscale morphology and surface roughness of the samples have been characterized using Atomic Force Microscope (AFM). The surface roughnesses obtained from AFM have been compared using surface profiler. From the results we can say that the roughness values are dependent on the surface roughness of the substrate. The glass substrate was relatively smoother than the titanium plate and hence lower layer roughness was obtained. From AFM a unique nano-pattern of a boomerang shaped titanium oxide layer on glass substrate have been obtained. The boomerang shaped nano-scale pattern was found to be smaller when the layer was deposited at higher sputtering power. This indicated that the morphology of the deposited titanium oxide layer has been influenced by the sputtering power.

Influence of initial texture on the microstructural instabilities during compression of commercial ?-Titanium at 25 °C to 400 °C

Cylindrical specimens of textured commercial pure alpha-titanium plate, cut with the cylinder axis along the rolling direction for one set of experiments and in the long transverse direction for the other set, were compressed at strain rates in the range of 0.001 to 100 s-1 and temperatures in the range of 25-degrees-C to 400-degrees-C. At strain rates greater-than-or-equal-to 1 s-1, both sets of specimens exhibited adiabatic shear bands, but the intensity of shear bands was found to be higher in the rolling direction specimens than in the long transverse direction specimens. At strain rates -0.1 s-1, the material deformed in a microstructurally inhomogeneous fashion. For the rolling direction specimens, cracking was observed at 100-degrees-C and at strain rates -0.1 s-1. This is attributed to dynamic strain aging. Such cracking was not observed in the long transverse specimens. The differences in the intensity of adiabatic shear bands and that of dynamic strain aging between the two sets of test specimens are attributed to the strong crystallographic texture present in these plates.

Finite Element Modeling for Development and Optimization of a Bone Plate for Mandibular Fracture in Dogs

This study aimed to develop a plate to treat fractures of the mandibular body in dogs and to validate the project using finite elements and biomechanical essays. Mandible prototypes were produced with 10 oblique ventrorostral fractures (favorable) and 10 oblique ventrocaudal fractures (unfavorable). Three groups were established for each fracture type. Osteosynthesis with a pure titanium plate of double-arch geometry and blocked monocortical screws offree angulanon were used. The mechanical resistance of the prototype with unfavorable fracture was lower than that of the fcworable fracture. In both fractures, the deflection increased and the relative stiffness decreased proportionally to the diminishing screw number The finite element analysis validated this plate study, since the maximum tension concentration observed on the plate was lower than the resistance limit tension admitted by the titanium. In conclusion, the double-arch geometry plate fixed with blocked monocortical screws has sufficient resistance to stabilize oblique,fractures, without compromising mandibular dental or neurovascular structures. J Vet Dent 24 (7); 212 - 221, 2010

Predicting the fatigue life of internal fracture fixation plates

Failures of fracture fixation plates, often related to fatigue fractures of the implants, have been reported (Banovetz et al, 1996). While metallurgical defects can usually be excluded, many of these fractures can be explained with the biomechanical situation. This study investigated the biomechanics of two clinical cases, both of which used a 14-hole locking compression plate. In the first case, a titanium plate was used in a rigid configuration with 12 screws resulting in plate breakage after 7 weeks (Sommer et al, 2003). In the second case, a stainless steel plate, which endured the entire healing process, was used in a flexible application with only 6 screws.

A comparative study of the physical properties of conventional and Grander-modified adhesive systems

Purpose: The objective of this study was to evaluate the influence of the Grander technology in reducing the surface tension and contact angle of a self-etch adhesive system. Methods: Distilled water and Xeno III self-etch adhesive system (Dentsply) were modified by physical contact with the Flexible unit Grander system to revitalize water, for 48 hours, resulting in four groups: Group 1 - Xeno III under normal conditions; Group 2 - Xeno III modified by Grander; Group 3 - distilled water under normal conditions; Group 4 - distilled water system modified by the Grander system;. Surface tension and contact angle (dentin substrate and titanium plate) of the adhesive system and water in normal and Grander-modified conditions was measured with a goniometer. Data were analyzed by ANOVA and Tukey test (5%). Results: Grander technology reduced the surface tension of water but not of the adhesive system Xeno III. The contact angle property of the adhesive ystem was not affected. Conclusion: Grander technology did not interfere with the surface tension and contact angle physical properties of the Xeno III self-etch adhesive system. Copyright: © 2011 Gonçalves et al.;.

Vascular pericranial graft: A viable resource for frontal sinus obliteration

Inappropriate treatments of frontal sinus fractures may lead to serious complications, such as mucopyocele, meningitis, and brain abscess. Assessment of nasofrontal duct injury is crucial, and nasofrontal duct injury requires sinus obliteration, which is often accomplished by autologous grafts such as fat, muscle, or bone. These avascular grafts have an increased risk of resorption and infection, as well as donor site morbidity. For these reasons, pericranial flap, which is vascular, should be used for frontal sinus obliteration. The pericranial flap presented with less morbidity procedure and has decreased infection rates, which justifies its use in frontal sinus obliteration. This paper aims to report a case of a comminuted frontal sinus fracture in a 29-year-old man who was successfully treated by frontal sinus obliteration, using pericranial local flap. The patient was followed up postoperatively for 16 months without infection. Copyright © 2013 by Mutaz B. Habal, MD.

Anterior pericranial flap for frontal sinus duct obliteration: Is it a valuable resource?

Inappropriate treatments of frontal sinus fractures may lead to serious complications, such as mucopyocele, meningitis, and brain abscess. Assessment of nasofrontal duct injury is crucial, and nasofrontal duct injury requires sinus obliteration, which is often accomplished by autogenous grafts such as fat, muscle, or bone. These avascular grafts have an increased risk of resorption and infection and donor site morbidity. For these reasons, pericranial flap, which is vascular, should be used for frontal sinus obliteration. The pericranial flap presented with less morbidity procedure and has decreased infection rates, which justifies its use in frontal sinus obliteration. This study aimed to report a case of a comminuted frontal sinus fracture with a brief literature review, regarding the use of pericranial flap. The authors report a case of a 23-year-old male subject with a severely comminuted fracture of the anterior and posterior walls of the frontal sinus. The patient was successfully treated by cranialization with frontal sinus duct obliteration, using anterior pericranial flap. The patient was followed up for 16 months with no postoperative complication, such as infection. Pericranial flap is a good resource for frontal sinus duct obliteration because it is a durable and well-vascularized flap, which determines low rates of postoperative complications. Copyright © 2013 by Mutaz B. Habal, MD.

Avaliação da intrusão dos molares superiores pela técnica de ancoragem com miniplacas de titânio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dentina humana e bovina: estudo comparativo das propriedades físicas e características da hibridização de sistemas adesivos convencionais ou grander modificados: análise em mev

A adesão longitudinal continua a representar um dos maiores desafios da Odontologia moderna. Uma nova proposta para o estabelecimento do equilíbrio da adesão aos tecidos dentários surge, baseada na observação dos resultados obtidos com a tecnologia Grander para revitalização da água. Objetiva-se com o estudo verificar a influência dessa tecnologia nas propriedades físicas de dois sistemas adesivos (convencional e autocondicionante) à partir da medição da tensão superficial e do ângulo de contato; e avaliar a formação e a qualidade da camada híbrida em dentina humana e bovina. A tensão superficial de quatro diferentes líquidos (água, Single Bond- 3M, Primer do Clearfil SE Bond -Kuraray, e Bond do Clearfil SE-Kuraray), foi medida antes e após a modificação pelo procedimento Grander em aparelho goniômetro (Ramé-hart). O ângulo de contato com três substratos distintos (placa de titânio, dentina humana e dentina bovina), foi medido para os quatro líquidos também antes e após a modificação pelo procedimento Grander, também em goniômetro. A formação e qualidade da camada híbrida, foi avaliada em MEV, a partir da confecção de corpos de prova dos substratos humano e bovino, devidamente embutidos, preparados em lixas de variada granulação até a exposição de dentina, submetidos ao procedimento adesivo (SB ou CSEB) normal ou grander modificado, recebendo ao final dupla camada de resina composta Z250-3M, fotopolimerizada por 40s. Após armazenamento em estufa bacteriológica por 24h, os procedimentos para análise ao MEV foram realizados (fixação, desidratação, secagem e metalização). A estatística de Análise de Variância ANOVA e Teste de Tukey 5% revelou que: houve redução estatisticamente significante da tensão superficial para todos os líquidos Grander modificados; houve redução estatisticamente... (Resumo completo, clicar acesso eletrônico abaixo)

The effect of a slow mode of BMP-2 delivery on the inflammatory response provoked by bone-defect-filling polymeric scaffolds

We investigated the inflammatory response to, and the osteoinductive efficacies of, four polymers (collagen, Ethisorb, PLGA and Polyactive) that bore either an adsorbed (fast-release kinetics) or a calcium-phosphate-coating-incorporated (slow-release kinetics) depot of BMP-2. Titanium-plate-supported discs of each polymer (n = 6 per group) were implanted at an ectopic (subcutaneous) ossification site in rats (n = 48). Five weeks later, they were retrieved for a histomorphometric analysis of the volumes of ectopic bone and foreign-body giant cells (a gauge of inflammatory reactivity), and the degree of polymer degradation. For each polymer, the osteoinductive efficacy of BMP-2 was higher when it was incorporated into a coating than when it was directly adsorbed onto the material. This mode of BMP-2 carriage was consistently associated with an attenuation of the inflammatory response. For coated materials, the volume density of foreign-body giant cells was inversely correlated with the volume density of bone (r(2) = 0.96), and the volume density of bone was directly proportional to the surface-area density of the polymer (r(2) = 0.97). Following coating degradation, other competitive factors, such as the biocompatibility and the biodegradability of the polymer itself, came into play.

Effect on infection resistance of a local antiseptic and antibiotic coating on osteosynthesis implants: an in vitro and in vivo study

The purpose of this study was to acquire information about the effect of an antibacterial and biodegradable poly-L-lactide (PLLA) coated titanium plate osteosynthesis on local infection resistance. For our in vitro and in vivo experiments, we used six-hole AO DC minifragment titanium plates. The implants were coated with biodegradable, semiamorphous PLLA (coating about 30 microm thick). This acted as a carrier substance to which either antibiotics or antiseptics were added. The antibiotic we applied was a combination of Rifampicin and fusidic acid; the antiseptic was a combination of Octenidin and Irgasan. This produced the following groups: Group I: six-hole AO DC minifragment titanium plate without PLLA; Group II: six-hole AO DC minifragment titanium plate with PLLA without antibiotics/antiseptics; Group III: six-hole AO DC minifragment titanium plate with PLLA + 3% Rifampicin and 7% fusidic acid; Group IV: six-hole AO DC minifragment titanium plate with PLLA + 2% Octenidin and 8% Irgasan. In vitro, we investigated the degradation and the release of the PLLA coating over a period of 6 weeks, the bactericidal efficacy of antibiotics/antiseptics after their release from the coating and the bacterial adhesion of Staphylococcus aureus to the implants. In vivo, we compared the infection rates in white New Zealand rabbits after titanium plate osteosynthesis of the tibia with or without antibacterial coating after local percutaneous bacterial inoculations at different concentrations (2 x 10(5)-2 x 10(8)): The plate, the contaminated soft tissues and the underlying bone were removed under sterile conditions after 28 days and quantitatively evaluated for bacterial growth. A stepwise experimental design with an "up-and-down" dosage technique was used to adjust the bacterial challenge in the area of the ID50 (50% infection dose). Statistical evaluation of the differences between the infection rates of both groups was performed using the two-sided Fisher exact test (p < 0.05). Over a period of 6 weeks, a continuous degradation of the PLLA coating of 13%, on average, was seen in vitro in 0.9% NaCl solution. The elution tests on titanium implants with antibiotic or antiseptic coatings produced average release values of 60% of the incorporated antibiotic or 62% of the incorporated antiseptic within the first 60 min. This was followed by a much slower, but nevertheless continuous, release of the incorporated antibiotic and antiseptic over days and weeks. At the end of the test period of 42 days, 20% of the incorporated antibiotic and 15% of the incorporated antiseptic had not yet been released from the coating. The antibacterial effect of the antibiotic/antiseptic is not lost by integrating it into the PLLA coating. The overall infection rate in the in vivo investigation was 50%. For Groups I and II the infection rate was both 83% (10 of 12 animals). In Groups III and IV with antibacterial coating, the infection rate was both 17% (2 of 12 animals). The ID50 in the antibacterial coated Groups III and IV was recorded as 1 x 10(8) CFU, whereas the ID50 values in the Groups I and II without antibacterial coating were a hundred times lower at 1 x 10(6) CFU, respectively. The difference between the groups with and without antibacterial coating was statistically significant (p = 0.033). Using an antibacterial biodegradable PLLA coating on titanium plates, a significant reduction of infection rate in an in vitro and in vivo investigation could be demonstrated. For the first time, to our knowledge, we were able to show, under standardized and reproducible conditions, that an antiseptic coating leads to the same reduction in infection rate as an antibiotic coating. Taking the problem of antibiotic-induced bacterial resistance into consideration, we thus regard the antiseptic coating, which shows the same level of effectiveness, as advantageous.

Investigation of phenol degradation : True reaction kinetics on fixed film titanium dioxide photocatalyst

This study of photocatalytic oxidation of phenol over titanium dioxide films presents a method for the evaluation of true reaction kinetics. A flat plate reactor was designed for the specific purpose of investigating the influence of various reaction parameters, specifically photocatalytic film thickness, solution flow rate (1–8 l min−1), phenol concentration (20, 40 and 80 ppm), and irradiation intensity (70.6, 57.9, 37.1and 20.4 W m−2), in order to further understand their impact on the reaction kinetics. Special attention was given to the mass transfer phenomena and the influence of film thickness. The kinetics of phenol degradation were investigated with different irradiation levels and initial pollutant concentration. Photocatalytic degradation experiments were performed to evaluate the influence of mass transfer on the reaction and, in addition, the benzoic acid method was applied for the evaluation of mass transfer coefficient. For this study the reactor was modelled as a batch-recycle reactor. A system of equations that accounts for irradiation, mass transfer and reaction rate was developed to describe the photocatalytic process, to fit the experimental data and to obtain kinetic parameters. The rate of phenol photocatalytic oxidation was described by a Langmuir–Hinshelwood type law that included competitive adsorption and degradation of phenol and its by-products. The by-products were modelled through their additive effect on the solution total organic carbon.

Design of antenna-coupled lumped-element titanium nitride KIDs for long-wavelength multi-band continuum imaging

Many applications in cosmology and astrophysics at millimeter wavelengths including CMB polarization, studies of galaxy clusters using the Sunyaev-Zeldovich effect (SZE), and studies of star formation at high redshift and in our local universe and our galaxy, require large-format arrays of millimeter-wave detectors. Feedhorn and phased-array antenna architectures for receiving mm-wave light present numerous advantages for control of systematics, for simultaneous coverage of both polarizations and/or multiple spectral bands, and for preserving the coherent nature of the incoming light. This enables the application of many traditional "RF" structures such as hybrids, switches, and lumped-element or microstrip band-defining filters.

Simultaneously, kinetic inductance detectors (KIDs) using high-resistivity materials like titanium nitride are an attractive sensor option for large-format arrays because they are highly multiplexable and because they can have sensitivities reaching the condition of background-limited detection. A KID is a LC resonator. Its inductance includes the geometric inductance and kinetic inductance of the inductor in the superconducting phase. A photon absorbed by the superconductor breaks a Cooper pair into normal-state electrons and perturbs its kinetic inductance, rendering it a detector of light. The responsivity of KID is given by the fractional frequency shift of the LC resonator per unit optical power.

However, coupling these types of optical reception elements to KIDs is a challenge because of the impedance mismatch between the microstrip transmission line exiting these architectures and the high resistivity of titanium nitride. Mitigating direct absorption of light through free space coupling to the inductor of KID is another challenge. We present a detailed titanium nitride KID design that addresses these challenges. The KID inductor is capacitively coupled to the microstrip in such a way as to form a lossy termination without creating an impedance mismatch. A parallel plate capacitor design mitigates direct absorption, uses hydrogenated amorphous silicon, and yields acceptable noise. We show that the optimized design can yield expected sensitivities very close to the fundamental limit for a long wavelength imager (LWCam) that covers six spectral bands from 90 to 400 GHz for SZE studies.

Excess phase (frequency) noise has been observed in KID and is very likely caused by two-level systems (TLS) in dielectric materials. The TLS hypothesis is supported by the measured dependence of the noise on resonator internal power and temperature. However, there is still a lack of a unified microscopic theory which can quantitatively model the properties of the TLS noise. In this thesis we derive the noise power spectral density due to the coupling of TLS with phonon bath based on an existing model and compare the theoretical predictions about power and temperature dependences with experimental data. We discuss the limitation of such a model and propose the direction for future study.

Enhancement of Wear and Corrosion Resistance of Beta Titanium Alloy by Laser Gas Alloying with Nitrogen

The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4 V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family, the quaternary Ti-Nb-Zr-Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4 V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must be resolved before commercialising in the orthopaedic market. In this work, a newly-developed laser surface treatment technique was employed to improve the surface properties of Ti-35.3Nb-7.3Zr-5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing incidence x-ray diffraction (GI-XRD) and x-ray photoelectron spectroscopy (XPS). The wear and corrosion resistance were evaluated by pin-on-plate sliding test and anodic polarisation test in Hanks’ solution. The experimental results were compared with the untreated (or base) TNZT material. The research findings showed that the laser surface treatment technique reported in this work can effectively improve the wear and corrosion resistance of TNZT.

Evaluation of in vitro resistance of titanium and resorbable (poly-L-DL-lactic acid) fixation systems on the mandibular angle fracture

The purpose of this study was to compare, by mechanical in vitro testing, a 2.0-mm system made with poly-L-DL-lactide acid with an analogue titanium-based system. Mandible replicas were used as a substrate and uniformly sectioned on the left mandibular angle. The 4-hole plates were adapted and stabilized passively in the same site in both groups using four screws, 6.0 mm long. During the resistance-to-load test, the force was applied perpendicular to the occlusal plane at three different points: first molar at the plated side; first molar at the contralateral side; and between the central incisors. At 1 mm of displacement, no statistically significant difference was found. At 2 mm displacement, a statistically significant difference was observed when an unfavourable fracture was simulated and the load was applied in the contralateral first molar and when a favourable fracture was simulated and the load was applied between the central incisors. At the failure displacement, a statistically significant difference was observed only when the favourable fracture was simulated and the load was applied on the first molar at the plated side. In conclusion, despite more failure, the poly-L-DL-lactic acid-based system was effective.