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Purpose: This study aimed to analyze and compare three-dimensional volumetric bone changes and stability of simultaneously placed dental implants following sinus augmentation using deproteinized human demineralized tooth matrix (dpDTM) and deproteinized bovine bone mineral (DBBM). Methods: Twenty-four patients who required lateral maxillary sinus floor augmentation with simultaneous dental implant placement were randomly assigned to receive either dpDTM (n = 12) or DBBM (n = 12). Cone-beam computed tomography and resonance frequency analysis of implant stability were conducted immediately after surgery and 6 months postoperatively. Changes in the graft sinus floor and graft height volumes in the sagittal and coronal views, along with the implant stability quotient (ISQ), were analyzed and compared. Results: Volumetric graft alteration was comparable between dpDTM (120.33 ± 77.48 mm3) and DBBM (108.51 ± 65.15 mm3) (p = 0.690). Reduction in the average graft height was also comparable: dpDTM group ranged from − 0.59 to − 0.93 mm and the DBBM group ranged from − 0.55 to − 0.82 mm (p > 0.05) at most examined levels. However, greater reduction in the mesial-graft height occurred in the dpDTM group (− 1.08 ± 0.70 mm vs. −0.58 ± 0.39 mm, p = 0.04). The ISQ values increased similarly in both groups to reach 70 at 6 months. Conclusion: dpDTM demonstrated comparable stability in graft volume and height during the healing process compared to DBBM and could serve as a viable alternative to DBBM for sinus floor augmentation with simultaneous implant placement. [ABSTRACT FROM AUTHOR]

The goal of the current work is to analyse the Zn scaffold porosity effects on its corrosion behavior. Organized porous network structure (OPNS) zinc samples with varying porosity were manufactured by a newly developed rapid tooling approach that combined 3D printing and microwave sintering. The outcomes of the OPNS Zn samples were also compared to the dense zinc sample. For the corrosion analysis, porous and dense zinc samples electrochemical corrosion testing were conducted in SBF electrolyte at 37 °C. The zinc samples morphological study was accessed by scanning electron microscopy (SEM). It was confirmed by the findings of the morphological study that the Zn samples contained randomly distributed micropores and designed or organized macropores. The zinc sample corrosion behavior in SBF was analyzed by potentiodynamic (PD) polarisation and electrochemical impedance spectroscopy (EIS) curves. In addition, an electrical equivalent circuit (EEC) model was developed using the EIS experimental data to establish an understanding of the corrosion behavior of Zn samples. Overall corrosion testing results demonstrate that the diffusion mechanism had an impact on the corrosion mechanism of Zn samples and diffusion mechanism during electrochemical reaction supported by the porosity of the sample. The Zn samples corrosion rate was found to be minimum for the dense sample (0.14 mm y−1), while it was maximum for the highest porosity OPNS Zn sample (0.66 mm y−1). The present study corrosion rate of Zn samples was comparable with the required value for bone implants. [ABSTRACT FROM AUTHOR]

Here, the results of a phase 1/2 single-arm trial (NCT03744026) assessing the safety and efficacy of blood-brain barrier (BBB) disruption with an implantable ultrasound system in recurrent glioblastoma patients receiving carboplatin are reported. A nine-emitter ultrasound implant was placed at the end of tumor resection replacing the bone flap. After surgery, activation to disrupt the BBB was performed every four weeks either before or after carboplatin infusion. The primary objective of the Phase 1 was to evaluate the safety of escalating numbers of ultrasound emitters using a standard 3 + 3 dose escalation. The primary objective of the Phase 2 was to evaluate the efficacy of BBB opening using magnetic resonance imaging (MRI). The secondary objectives included safety and clinical efficacy. Thirty-three patients received a total of 90 monthly sonications with carboplatin administration and up to nine emitters activated without observed DLT. Grade 3 procedure-related adverse events consisted of pre syncope (n = 3), fatigue (n = 1), wound infection (n = 2), and pain at time of device connection (n = 7). BBB opening endpoint was met with 90% of emitters showing BBB disruption on MRI after sonication. In the 12 patients who received carboplatin just prior to sonication, the progression-free survival was 3.1 months, the 1-year overall survival rate was 58% and median overall survival was 14.0 months from surgery. Recent work indicates that drug delivery to the brain can be improved through disruption of the blood brain barrier using low intensity pulsed ultrasound. Here, the authors report a phase I/II clinical trial investigating the combination of a nine-emitter implantable ultrasound device and carboplatin in patients with recurrent glioblastoma. [ABSTRACT FROM AUTHOR]

The propagation of elastic vibrations in rock samples in compression and under impacts to failure is investigated experimentally. Under impacts, a signal of acceleration was recorded in the samples, and the spectral density was calculated to determine velocities of elastic vibrations. It is found that under increasing load up to a pre-failure value, the P- and S-wave velocities grow, and the S-wave velocity increases by more than 50%. The acoustic Q-factor rises by 70%. The energy of the microseismic emission under pre-failure loads is two times higher than under low loads, and the high-amplitude spectral components generated under pre-failure loading are reflective of large discontinuities being formed. [ABSTRACT FROM AUTHOR]

The surface properties of artificial implants are responsible for contact, primary fixation, intermediate bonding and future stability with the host tissue and their suitable alteration can improve functionality of the implants. Here, a picosecond pulsed laser was employed to alter the surface properties of a widely used biomaterial, Ti64. Three types of samples with variation in average surface roughness, wettability and presence of oxide layer were prepared by changing the laser fluence and pulse overlapping factor. The influence of change in surface properties on electrochemical behavior, bio-corrosion and cytocompatibility and ossiointegration of the sample were investigated. Comparative studies showed an improvement in anticorrosive behavior of Ti64 alloy after laser treatment that is confirmed from the open-circuit potential, Tafel analysis and impedance spectroscopy in simulated body fluid. Furthermore, the non-toxic nature of laser-treated surface was established and was confirmed from the cytotoxicity studies on U2OS osteosarcoma cells. Comparable number of cells with no changes in nuclear morphologies were found to be adhered on laser-treated samples. Growth of hydroxayaptite on all samples was monitored 25 days after their immersion in simulated body fluid. Along with improved osseointegration capability, the laser-treated sample at a fluence of 0.12 J/cm2 and 58% laser pulse overlapping factor exhibited superior performance in all other tested aspects. This shows that the chosen experimental parameters suitably modified the surface to enhance its biocompatibility in all tests performed in this study. [ABSTRACT FROM AUTHOR]

This study investigated early bone formation using collagenated biphasic calcium phosphate (CBCP) with or without polynucleotide (PDRN). Third (P3) or fourth (P4) premolars of six male beagle dogs were extracted and 5-mm-high dehiscence defects were created, followed by 3D-printed implant placement. The buccal bone defects were grafted with (i) CBCP and collagen membrane or (ii) CBCP soaked in polydeoxyribonucleotide (CBCP/PDRN) and collagen membrane. Samples of the experimental sites were harvested at 2- and 6-weeks post-surgery. The specimens were evaluated with radiologic and histomorphometric analysis. No significant differences were found between the CBCP and CBCP/PDRN groups in the micro-CT analysis at 2 or 6 weeks. No significant differences were observed in bone-to-implant contact (BIC) or bone area fraction occupancy (BAFO) in buccal augmented and lingual non-augmented areas. In the qualitative analysis, the new bone (NB) area and NB proportion in buccal augmented areas showed significantly higher values in the CBCP/PDRN group than in the CBCP group at 2 and 6 weeks. Peri-implant buccal dehiscence defects with immediate 3D-printed implant placement were corrected using a collagen membrane and CBCP or CBCP/PDRN. PDRN might have the potential to facilitate early bone formation with sufficient stability over time in dehiscence defects. [ABSTRACT FROM AUTHOR]

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Dental implant failure is primarily due to peri-implantitis, a consequence of bacterial biofilm formation. Bacterial adhesion is strongly linked to micro-/nano-topographies of a surface; thus an assessment of surface texture parameters is essential to understand bacterial adhesion. In this study, mirror polished titanium samples (Ti6Al4V) were irradiated with a femtosecond laser (fs-L) at a wavelength of 1030 nm (infrared) with variable laser parameters (laser beam polarization, number, spacing and organization of the impacts). Images of 3-D topographies were obtained by focal variation microscopy and analyzed with MountainsMap software to measure surface parameters. From bacteria associated with peri-implantitis, we selected Porphyromonas gingivalis to evaluate its adhesion on Ti6Al4V surfaces in an in vitro study. Correlations between various surface parameters and P. gingivalis adhesion were investigated. We discovered that Sa value, a common measure of surface roughness, was not sufficient in describing the complexity of these fs-L treated surfaces and their bacterial interaction. We found that Sku, density and mean depths of the furrows, were the most accurate parameters for this purpose. These results provide important information that could help anticipate the bacterial adhesive properties of a surface based on its topographic parameters, thus the development of promising laser designed biofunctional implants. [ABSTRACT FROM AUTHOR]

To correlate fluorapatite thin films' morphology to their stability and bioactivity for temporary bioimplant applications, fluorapatite is ultrasonically spray-deposited on different substrates using chemical precursors. Mechanical agitation in phosphate-buffered saline solution is used to investigate the stability of the films aided with X-ray diffraction and electron microscopy for films' morphology and thickness. For bioactivity, the cell adhesion to the fluorapatite thin films is evaluated by growing HaCaT cells on the film surface. The films deposited on titanium are pure and polycrystalline. Agitation in solution leads to a thickness reduction of 18.3%, and 30.5% for the films deposited on alumina. However, the persistence of the films after agitation suggests partial degradability. The improved stability of fluorapatite on titanium is attributed to the layer plus island-like morphology that offers a reduced contact area with the surrounding solution compared with the island-like morphology of fluorapatite on alumina. These different morphologies can be understood in the context of a smaller lattice mismatch between the substrate and the film which results in the layer plus island-like morphology. HaCaT cell adhesion on Ti-fluorapatite film surfaces is better than the titanium reference and alumina-fluorapatite suggesting its bioactivity and the promise of spray-deposited FAP for orthopedic applications. [ABSTRACT FROM AUTHOR]

Purpose: In this study, we investigated the effects of leukocyte- and platelet-rich fibrin (L-PRF) on implant stability and alterations in the marginal bone surrounding posterior maxillary implants. Methods: This randomized clinical trial was conducted to compare the variable of L-PRF placement around maxillary implants. Resonance frequency analysis (RFA) was used to evaluate the implant stability immediately after surgery and at 1, 2, 4, 6, 8, and 12 weeks after surgery (t0 to t6, respectively). In addition, the amount of marginal bone changes around the implant at t6 was compared with the baseline using periapical radiography. Results: The RFA outcomes were statistically significant within each group (P < 0.001, Eta2 = 0.322); however, in none of the follow-ups and immediately after the surgery, there was a significant difference between the two groups in terms of the implant stability quotient (ISQ) scores (P > 0.05). At t0, the test and control groups' respective mean levels of marginal bone loss around the implants were 0.4836 mm and 0.7343 mm, significantly different from the corresponding values at t6. On the other hand, marginal bone loss around the implant was not significantly different between the two groups in t0 and t6 (P = 0.532). Conclusions: L-PRF did not improve the RFA outcomes of implants three months after implant placement, and changes in the ISQ values over time were the same in both groups. In addition, L-PRF had no superior effect on the marginal bone loss around the implants. Trial registration number: The research was registered in the Iranian Registry of Clinical Trials on 22 December 2020 (No: IRCT20200624047906N1), available at http://www.irct.ir [ABSTRACT FROM AUTHOR]

Design: The study conducted by Olmedo-Gaya et al. aimed to investigate the effects of various surgical techniques on the initial stability of implants placed in the posterior maxilla through a randomized controlled clinical trial. The study compared insertion torque (IT) and implant stability quotients (ISQ) among implants placed using under preparation, expanders, and standard surgical instrumentation. Case selection: The study enrolled 108 patients, each receiving one implant in the posterior maxilla region. Patients were distributed into three groups: group 1 (n = 36) with the under preparation technique, group 2 (n = 36) using the expander technique, and group 3 (n = 36) with conventional drilling. Data analysis: IT was measured using a torque indicator, while ISQ was recorded through resonance frequency analysis immediately post-surgery. The ISQ values were analyzed in relation to the patient's bone quality, categorized into types II, III, and IV. Results: ISQ values varied significantly with bone quality, being highest in type II (76.65) and type III (73.60), and lowest in type IV (67.34) bone, with a significant difference (p < 0.0001). The conventional drilling technique yielded lower ISQ values (69.31) compared to under preparation (74.29) and expander techniques (73.99), with statistical significance (p = 0.008 and p = 0.005, respectively). Conclusions: Surgical technique significantly influences primary stability in low-quality bone. Conventional drilling results in lower ISQ values, suggesting that alternative techniques such as under preparation or expanders should be used in low-quality bone to achieve better primary stability. Clinical relevance: For implants in low-quality bone, replacing the conventional drilling technique with under preparation or expander techniques can enhance primary stability. [ABSTRACT FROM AUTHOR]

Background and objective: Primary stability (PS) is remarkable for secondary stability and implant success. Surgical technique modifications seem to improve primary stability, especially in poor quality bone. The aim of this study was to compare the insertion torque (IT) and implant stability quotients (ISQ) of implants placed with underpreparation, expanders, and standard surgical instrumentation in different bone types. Material and methods: This randomized controlled clinical trial enrolled 108 patients (n=108 implants) distributed in three study groups: group 1 (n=36) underpreparation technique, group 2 (n=36) expander technique, and group 3 (n=36) conventional drilling. IT was recorded with a torque indicator. ISQ was recorded with resonance frequency analysis immediately after surgery. Results: ISQ values were associated with the patient's bone quality and were higher in bone quality type II (76.65) and type III (73.60) and lower in bone quality type IV (67.34), with statistically significant differences (p<0.0001). Lower stability results were obtained when conventional drilling (69.31) was used compared to the use of underpreparation (74.29) or expanders (73.99) with a level of significance of p=0.008 and p=0.005, respectively. Conclusions: The surgical technique influences the PS when there is low-quality bone. In low-quality bones, conventional drilling obtains lower ISQ values. Clinical relevance: Replace the conventional drilling technique for an alternative, underpreparation or expanders, in low-quality bone in order to achieve greater primary stability. [ABSTRACT FROM AUTHOR]

Nitrogen isotopes are widely used to study the trophic position of animals in modern food webs; however, their application in the fossil record is severely limited by degradation of organic material during fossilization. In this study, we show that the nitrogen isotope composition of organic matter preserved in mammalian tooth enamel (δ15Nenamel) records diet and trophic position. The δ15Nenamel of modern African mammals shows a 3.7‰ increase between herbivores and carnivores as expected from trophic enrichment, and there is a strong positive correlation between δ15Nenamel and δ15Nbone-collagen values from the same individuals. Additionally, δ15Nenamel values of Late Pleistocene fossil teeth preserve diet and trophic level information, despite complete diagenetic loss of collagen in the same specimens. We demonstrate that δ15Nenamel represents a powerful geochemical proxy for diet that is applicable to fossils and can help delineate major dietary transitions in ancient vertebrate lineages. Enamel-bound nitrogen isotopes in modern and fossil mammal teeth preserve dietary and trophic level information. This novel geochemical archive can be used to reconstruct trophic niche in ancient ecosystems. [ABSTRACT FROM AUTHOR]

Objectives: Stability values of mini-implants (MIs) are ambiguous. Survival data for MIs as supplementary abutments in reduced dentitions are not available. The aim of this explorative research was to estimate the 3-year stability and survival of strategic MIs after immediate and delayed loading by existing removable partial dentures (RPDs). Material and methods: In a university and three dental practices, patients with unfavorable tooth distributions received supplementary MIs with diameters of 1.8, 2.1, and 2.4 mm. The participants were randomly allocated to group A (if the insertion torque ≥ 35 Ncm: immediate loading by housings; otherwise, immediate loading by RPD soft relining was performed) or delayed loading group B. Periotest values (PTVs) and resonance frequency analysis (RFA) values were longitudinally compared using mixed models. Results: A total of 112 maxillary and 120 mandibular MIs were placed under 79 RPDs (31 maxillae). The 1st and 3rd quartile of the PTVs ranged between 1.7 and 7.8, and the RFA values ranged between 30 and 46 with nonrelevant group differences. The 3-year survival rates were 92% in group A versus 95% in group B and 99% in the mandible (one failure) versus 87% in the maxilla (eleven failures among four participants). Conclusions: Within the limitations of explorative analyses, there were no relevant differences between immediate and delayed loading regarding survival or stability of strategic MIs. Clinical relevance: The stability values for MIs are lower than for conventional implants. The MI failure rate in the maxilla is higher than in the mandible with cluster failure participants. Clinical trial registration: German Clinical Trials Register (Deutsches Register Klinischer Studien, DRKS-ID: DRKS00007589, www.germanctr.de), January 15, 2015. [ABSTRACT FROM AUTHOR]

Micro-rod YAG single crystals are the preferred laser crystals for laser gain mediums with a high power. However, brittle fracture and crack damages are easy to occur in the grinding process of micro-rod brittle crystals due to their large length-to-diameter ratio, high brittleness, and high hardness. In this work, the modal, frequency, and harmonic response of the transducer under ultrasonic elliptical vibration are analyzed by using finite element simulation. Then, the mechanical structure of ultrasonic elliptical vibration system was designed and optimized based on the ultrasonic elliptical vibration theory and finite element simulation. To verify the reliability of the transducer, ultrasonic vibration experiments were carried out to measure the resonance frequency, amplitude, and impedance characteristics of the transducer. The vibration synthesis experiments under different phase differences and voltages were performed to verify the rationality of the structural design of the ultrasonic elliptical vibration system. An experimental platform of ultrasonic elliptical vibration–assisted centerless grinding (UEVCG) was developed, and UEVCG tests of micro-rod YAG crystals were performed. The influences of the voltage, phase difference, and pallet inclined angle on surface roughness, peak-to-valley value, and cylindricity of the micro-rod YAG crystals were systematically analyzed. The ultrasonic elliptical vibration parameters were optimized based on the range analysis results of the orthogonal test. The results indicated that ultrasonic elliptical vibration effectively improved the surface quality and cylindricity of the micro-rod YAG crystals compared with traditional grinding. This work will not only enhance the understanding of the ultrasonic elliptical vibration principle, but also provide a technical support for precision and high-efficiency machining of micro-rod brittle materials. [ABSTRACT FROM AUTHOR]

An improved statistical method for determining the resonance frequencies of soils from spectral H/V ratios is presented. The combination of developed methodological and computational techniques makes it possible to identify with high reliability the resonance frequencies of the soil sequence and fundamental frequencies of the natural vibrations of structures and their elements based on engineering seismological observations. The authors demonstrate the possibility of refining the seismic soil model of a site and compiling spatial models of the change in depths of seismic boundaries of layers of the soil sequence from the results of frequency analysis of records of microseisms and seismic events. The use of the described engineering and seismological observations and methodological techniques makes it possible to instrumentally estimate the increase in amplitudes of vibrations of structures and their individual elements at resonance frequencies and obtain a sufficiently detailed seismometric floor-by-floor description of the vibrational characteristics of buildings and structures. [ABSTRACT FROM AUTHOR]

Objective: Resonance frequency analysis (RFA) provides an evaluation of implant stability over time. This analysis is a non-invasive, precise, and objective method. Several studies compare the RFA system with other devices. However, few investigations analyze repeatability and reproducibility between different operators. The aim of this study was to evaluate the intra- and inter-operator concordance of the Osstell® ISQ. Material and methods: RFA measurements were performed with Osstell® ISQ in a total of 37 implants placed in 21 patients. At the time of implant placement, 6 measurements per implant were taken by three different experienced operators. Three measurements were carried out consecutively and three by removing and placing the SmartPeg-Osstell® to assess intra-operator and inter-operator agreement. Results: Intra-operator concordance according to the intraclass correlation coefficient (ICC) showed high concordance. The ICC values were higher than 0.9 (p < 0.0001) for consecutive measures and alternative measures, being almost perfect of Landis & Koch classification. For inter-operator concordance The ICC was 0.709 (p < 0.0001) and 0.670 (p < 0.0001) for consecutive and alternative measures, respectively, both estimates being in the substantial category. In torque and ISQ values, no statistically significant differences were observed when operators and measurements were compared. Conclusions: Osstell® ISQ system was stable both in intra-operator and inter-operator measurements. This device has excellent repeatability and reproducibility, demonstrating reliability to measure the stability of dental implants. Clinical relevance: Resonance frequency analysis (RFA) is a non-invasive, objective, and reliable diagnostic method to determine the ideal moment to load the implant, as well as to predict possible failures. [ABSTRACT FROM AUTHOR]

Despite the numerous benefits of underground cabling in modern power distribution systems, the persistent challenge of fault detection and localization remains a critical concern. The reliability of underground power systems hinges upon swift and accurate fault detection to facilitate rapid grid restoration. Addressing this challenge, this study introduces a pioneering approach that integrates deep learning with conventional power signal analysis techniques, with a specific emphasis on frequency domain analysis. Key to the proposed method is the exploitation of the resonance frequency behavior exhibited by underground power cables in response to signal fluctuations. These resonance frequencies, inherently linked to cable parameters, offer a unique insight into fault detection and location. By leveraging this feature, the proposed methodology enables precise identification and location of faults. This study introduces a pioneering approach that integrates long short-term memory networks with conventional power signal analysis techniques with a specific emphasis on frequency domain analysis. Central to the approach is the utilization of the system’s normal resonance frequency as a benchmark for training the deep learning network. Through the induction of simulated faults at various positions along the cable network and subsequent analysis of resulting resonance frequency variations, the network is effectively trained to discern faults accurately. Validation of the proposed methodology is conducted through extensive MATLAB simulations on a representative network. The outcomes validate the method’s effectiveness and precision, highlighting its capacity to improve the dependability and efficiency of subterranean power distribution networks. [ABSTRACT FROM AUTHOR]

The aims of this study were to analyze prospectively and comparatively the peri-implant bone crest levels, bone density, stability and success rate of implants with different surface treatments in human edentulous mandibles. Twenty edentulous patients were selected. Four different implants were placed between the mental foramen. Four groups were evaluated: (1) laser-modified surface (LASER), (2) surface modified by laser with deposition of apatites (LASER + HA), (3) surface modified by double acid etching (ACID, Implacil De Bortoli) and (4) surface modified by sandblasting and acid etching (SLActive®, Straumann). Clinical, radiographic, resonance frequency and tomographic analyses were used. After 4 months, mandibular fixed implant prostheses were installed. Clinical and radiographic analyses were performed at times T0 (immediately after implant placement), T1 (15 days), T2 (30 days), T3 (60 days), T4 (90 days), T5 (120 days), T6 (180 days) and T7 (360 days), post-implant placement. The resonance frequency analysis (RFA) was measured at T0, T4, T6 and T7. The tomographic analysis was performed at T0, T4 and T7. In the radiographic bone density analysis, a statistical difference was found between the SLActive® and LASER + HA groups at T4 (p < 0.05). Statistical differences were observed in RFA at T4 (90 days), between the SLActive® and LASER groups (p < 0.05) and between the SLActive® and LASER + HA groups (p < 0.05). At T6 and T7, statistical differences were found between the SLActive® group and all other implant surfaces (p < 0.01). The experimental surfaces analyzed showed encouraging positive outcomes compared to those of the SLActive® surface. Long-term follow-up should be performed to confirm these results. [ABSTRACT FROM AUTHOR]

Objectives: Fractal analysis is a mathematical method used for the calculation of bone trabeculation and lacunarity. This study aims to evaluate the relationship between resonance frequency analysis (RFA) and fractal dimension (FD) of peri-implant bone to determine the preload stability of implants. Materials and methods: In this study, the results of the fractal analysis calculated from the resonance frequency analysis results taken in the 3rd month of the patients who underwent 2-stage implant by the same doctor and the radiographs taken in the same session were evaluated. A hundred implants in 20 patients were applied in this study. The implant stability quotient (ISQ) values of the implants and fractal dimension values of the peri-implant bone were calculated. Results: The findings showed that the ISQ1 (p = 0.008), ISQ2 (p = 0.038), ROI2 (p = 0.013), and ROI3 (p < 0.001) values were statistically significantly higher in men than women. The ISQ1 (p = 0.003), ISQ2 (p = 0.013), ROI1 (p = 0.011), and ROI3 (p < 0.001) of the mandible were statistically higher than the maxilla. The fractal dimension cut-off value to assess prosthetic loading was found 1.198. Conclusion: Fractal analysis is a non-invasive method that can be used in conjunction with clinical examination in the prosthetic loading decision of implants. It is a valuable parameter that can be used without the need for an extra device when it is necessary to reduce the clinical study time. Clinical relevance: Calculating the fractal dimension of the peri-implant bone is a practical, economical, and applicable method for clinicians. FD calculated from panoramic radiographs used for diagnosis in routine treatments in clinics where access to the necessary devices for ISQ measurement is not available will contribute to clinical practice. [ABSTRACT FROM AUTHOR]

Systems for transcutaneous inductive power transfer based on class E power amplifiers with series and parallel topologies for compensation of reactive power in the receiving part of the system were compared. The system with parallel compensation at the resonance frequency was shown to be a constant current source. In turn, in systems with series compensation, two possible frequencies can be selected, above and below the resonant frequency, at which the system is a constant voltage source. [ABSTRACT FROM AUTHOR]

Hyperbaric oxygen therapy (HBOT) has beneficial effects for patients complaining of poor bone healing such as related to diabetes mellitus. However, it is known that changing pressure conditions might cause dental barotrauma in the oral cavity. The aim of this study was to evaluate implant mechanical stability under HBOT pressure. Thirty-five implants were placed in bone blocks divided into five groups as control, 1, 3, 5, 7 HBOT cycles. In one cycle, 2.4 bar 100% oxygen pressure was performed. Implants' stabilities were measured with resonance frequency analysis (RFA) and removal torque (RT) meter device. Data were analyzed using Shapiro Wilk, ANOVA, and Tukey HSD tests for RFA and RT values considering p < 0.05 as the statistical significance level. RFA and RT values were compared by Pearson correlation coefficiency. RFA values of 5 and 7 HBOT cycles were significantly lower than 1, 3 HBOT and control group (p < 0.001). There was no statistical difference between 5 and 7 HBOT cycles RFA values. HBOT pressure simulation slightly but statistically decreased the stability for the implants exposed to 5 and 7 HBOT cycles. Highlights: The primary stability of an implant is the crucial factor for achieving osseointegration. There is no experimental study showing the effect of hyperbaric oxygen therapy (HBOT) pressure on mechanical stability of implants. This mechanical study demonstrated 5 and 7 HBOT sessions had a slightly reducing effect on immediate implant stability. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate biphasic calcium phosphate coating (BCPC) on the secondary stability of dental implants compared to sand-blasted and acid-etched (SLA) implants. Materials and Methods: This is a split-mouth study. Thirty subjects (20 males and ten females) underwent a dental implant procedure to replace mandibular first or second molars bilaterally. The subjects were randomly assigned to BCPC or SLA groups. The resonance frequency analysis measurements were performed two, four, six, and eight weeks after the implant placement. Results: Sixty implants were placed in the two groups (30 implants per group). The mean ISQ was 52.26 ± 3.73 in group 1 and 50.21 ± 2.59 in group 2 on day 14 after the implant insertion, 63.20 ± 2.76 in group 1 and 58.80 ± 2.14 in group 2 on day 28, 72.30 ± 3.15 in group 1 and 64.53 ± 3.19 in group 2 on day 42, and 78.70 ± 1.56 in group 1 and 71.63 ± 3.22 in group 2 on day 56. The data analysis demonstrated significant differences between the two groups in terms of the mean ISQ at various evaluation times. Conclusion: Regarding ISQ measurements, the secondary stability in BCPC implants may be higher compared to SLA implants in two months after implant insertion. [ABSTRACT FROM AUTHOR]

Skin-integrated electronics, also known as electronic skin (e-skin), are rapidly developing and are gradually being adopted in biomedical fields as well as in our daily lives. E-skin capable of providing sensitive and high-resolution tactile sensations and haptic feedback to the human body would open a new e-skin paradigm for closed-loop human–machine interfaces. Here, we report a class of materials and mechanical designs for the miniaturization of mechanical actuators and strategies for their integration into thin, soft e-skin for haptic interfaces. The mechanical actuators exhibit small dimensions of 5 mm diameter and 1.45 mm thickness and work in an electromagnetically driven vibrotactile mode with resonance frequency overlapping the most sensitive frequency of human skin. Nine mini actuators can be integrated simultaneously in a small area of 2 cm × 2 cm to form a 3 × 3 haptic feedback array, which is small and compact enough to mount on a thumb tip. Furthermore, the thin, soft haptic interface exhibits good mechanical properties that work properly during stretching, bending, and twisting and therefore can conformally fit onto various parts of the human body to afford programmable tactile enhancement and Braille recognition with an accuracy rate over 85%. [ABSTRACT FROM AUTHOR]

All physical oscillators are subject to thermodynamic and quantum perturbations, fundamentally limiting measurement of their resonance frequency. Analyses assuming specific ways of estimating frequency can underestimate the available precision and overlook unconventional measurement regimes. Here we derive a general, estimation-method-independent Cramer Rao lower bound for a linear harmonic oscillator resonance frequency measurement uncertainty, seamlessly accounting for the quantum, thermodynamic and instrumental limitations, including Fisher information from quantum backaction- and thermodynamically driven fluctuations. We provide a universal and practical maximum-likelihood frequency estimator reaching the predicted limits in all regimes, and experimentally validate it on a thermodynamically limited nanomechanical oscillator. Low relative frequency uncertainty is obtained for both very high bandwidth measurements (≈10−5 for τ = 30 μs) and measurements using thermal fluctuations alone (<10−6). Beyond nanomechanics, these results advance frequency-based metrology across physical domains. Thermodynamic and quantum fluctuations limit the accuracy with which conventional methods can measure observables, often depending on the method chosen. Here, information theory is employed to determine the minimum uncertainty in the resonant frequency of a harmonic oscillator in a method-independent way. [ABSTRACT FROM AUTHOR]

Background: The aim of the current study was to comparatively assess the primary stability of different Straumann® implant designs (BLX, Straumann Tapered Effect, Bone Level Tapered, and Standard Plus) via resonance frequency analysis by using an implant insertion model in freshly slaughtered bovine ribs with and without cortical bone. Tapered Effect (4.1 × 10 mm), Bone Level Tapered (4.1 × 10 mm), Standard Plus (4.1 × 10 mm), and BLX (4.0 × 10 mm) implants were inserted into the distal epiphysis on the longitudinal axis of the freshly slaughtered bovine ribs. As a control, implants with the same sizes were inserted into the proximal diaphysis. The stability of the implants was examined with resonance frequency analysis. Results: BLX and Tapered Effect implants showed higher implant stability quotient values in both study and control groups. All implant systems showed a significant decrease of mechanical anchorage in the study group. BLX and Bone Level Tapered designs had a significantly lower loss of mechanical anchorage in the lack of cortical bone. Conclusion: Both Tapered Effect and BLX designs could ensure sufficient initial stability; however, BLX implants could be an appropriate option in the lack of cortical bone and poor bone quality at the implant recipient site. Clinical relevance: BLX is a novel implant system, which could be especially beneficial in the presence of spongious bone type at posterior maxillae. [ABSTRACT FROM AUTHOR]

Purpose: In this work, we had an object to obtain optimum design method of the ultrasonic transducers with high efficiency and large output power. For this purpose, we opted for the ultrasonic radiator model with 10 elements and conducted a detailed study of one's design method. Methods: The electro-mechanical equivalent circuit for the longitudinal vibration of the HPU radiator is derived, the resonance frequency equations are obtained, and also the structure dimensions for the longitudinal vibration of the radiator are optimized. At first, the characteristics of the HPU radiator are studied using the numerical method. As a supplementary means to verify the numerical results, the vibration of the HPU radiator is also studied using FEM in this section. The resonance frequency and the vibrational displacement distribution are numerically simulated and experimentally measured. Results: The displacement correspondent to emitting face is maximized: gain factors of Langevin transducer, booster, and horn are 1.75, 2.50, and 2.80, respectively; therefore, whole gain factor of our ultrasonic radiator is 12.25. From the analysis and measured results in this work, it can be seen that by selection the system with 10 elements and structural optimization, the radiation dimension and vibration amplitude of the radiator can be effectively improved. Conclusion: The resonance frequency and the displacement field of the radiator are measured, which are in agreement with the theoretical and analysis results. The results validated that the longitudinal vibration excited by Langevin transducer can be effectively amplified by the booster. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the effects of ultraviolet (UV) photofunctionalization on the stability of implants during the early phase in the posterior region of the maxilla. The study was a randomized double-blinded clinical trial. Half of the participants received conventional commercial implants while the other half received UV-irradiated implants. The surgical sites were classified into three bone quality groups (II, III, IV) based on the grayscale value measured on cone-beam computed tomography. The values obtained from resonance frequency analysis were recorded immediately after implant placement and at 4 weeks and at 4 months postoperatively. The marginal bone level of the implants was evaluated using periapical radiographs at 4 weeks, 4 months, and 1 year postoperatively. Results: Fifty-seven implants placed in 34 participants were analyzed in this study. In group III, significant differences were observed in terms of the differences of resonance frequency analysis values at 4 weeks (p = 0.004) and 4 months (p = 0.017) postoperatively. In group II, the UV-treated group showed significantly lesser bone loss at 4 weeks post-operatively (p = 0.037). Conclusions: Within the limitation of the present study, we concluded that UV surface treatment on implants may increase the initial stability in the region of the maxilla with poor bone quality. [ABSTRACT FROM AUTHOR]

Heart Rate Variability Biofeedback (HRVB) is based on breathing at an optimal rate (or resonance frequency, RF) corresponding to the respiratory sinus arrhythmia (RSA). Our aim is to check whether the RF is a stable factor and analyse the HRV parameters individually per each breathing rate, comparing it with free slow breathing. A sample of 21 participants were trained in a test–retest HRVB protocol. The results indicated that RF changed between Test and Retest sessions in 66.7% of participants. This instability could be related to the average of interbeat interval (IBI). HRV time domain parameters (SDNN and RMSSD) were significantly higher for RF than for other breathing rates, including 6 breath/min and free slow breathing. Free slow breathing showed a lower heart rate averages than RF and other slow breathing rates. Overall, our study suggests the relevance of assessing RF individually and before each HRVB session, because the maximum cardiovascular benefits in terms of increasing HRV were found only at RF. Thus, breathing at the individualized and momentary frequency of resonance increases cardiac variability. [ABSTRACT FROM AUTHOR]

Subsurface structure survey based on horizontal-to-vertical (H/V) spectral ratios is widely conducted. The major merit of this survey is its convenience to obtain a stable result using a single station. Spatial variations of H/V spectral ratios are well-known phenomena, and it has been used to estimate the spatial fluctuation in subsurface structures. It is reasonable to anticipate temporal variations in H/V spectral ratios, especially in areas like geothermal fields, carbon capture and storage fields, etc., where rich fluid flows are expected, although there are few reports about the temporal changes. In Okuaizu Geothermal Field (OGF), Japan, dense seismic monitoring was deployed in 2015, and continuous monitoring has been consistent. We observed the H/V spectral ratios in OGF and found their repeated temporary drops. These drops seemed to be derived from local fluid activities according to a numerical calculation. Based on this finding, we examined a coherency between the H/V spectral ratios and fluid activities in OGF and found a significance. In conclusion, monitoring H/V spectral ratios can enable us to grasp fluid activities that sometimes could lead to a relatively large seismic event. [ABSTRACT FROM AUTHOR]

Background: Nicotine can have detrimental effects on dental implant osseointegration. This study aimed to evaluate the influence of systemic l-arginine supplement on the osseointegration of dental implants in nicotine consumer dogs. Methods: Twelve 1-year Labrador Retriever dogs had their right and left third and fourth mandibular premolars removed, and the sockets were left to heal for 6 months. Dogs were randomly divided into three groups (n = 16): group 1—0.2 mg/kg nicotine was injected twice daily; group 2—0.2 mg/kg nicotine was injected twice daily in addition to 200 mg/kg l-arginine capsules taken orally; and group 3—placebo. Forty-eight dental implants were inserted into the healed sockets of the dog's mandible and were assessed by implant stability quotient (ISQ) using resonance frequency analysis (RFA) during 4 weeks and insertion and removal torque value analysis. Results: No implant failure occurred during the study period. The change in torque value between insertion and removal was similar in the placebo and nicotine+arginine consumer dogs (p = 0.276), which shows a positive effect of arginine supplementation in nicotine consumers. There was a significant difference in torque value change between nicotine+arginine vs. nicotine consumers (p = 0.049) and placebo vs. nicotine (p = 0.003). After 4 weeks, the placebo had the most significant improvement in torque value (47.0 ± 16.9), followed by nicotine+arginine (25.1 ± 37.8), and the worst torque value was for the nicotine group (− 5.7 ± 24.0) pound per inch. The results show that except in the first week, there are significant differences in ISQ between the groups in different periods. ISQ in all of the groups has reduced at first but then increased over time. At the time of implant placement, insertion torque was significantly higher in the nicotine consumer group than the nicotine+arginine consumer group and placebo group (p = 0.020). Conclusion: Arginine supplementation promotes bone healing and implant primary stability by improving dental implant osseointegration biomechanical characteristics. [ABSTRACT FROM AUTHOR]

The town of Haenam in southwest Korea lies partially on reclaimed coastal land and experienced an unprecedented earthquake swarm during April and May 2020. Construction of a new town in the area means that there is demand to evaluate the seismic hazard caused by site-specific amplification of seismic ground motions by artificial unconsolidated cover. We used a microtremor horizontal-to-vertical spectral ratio (HVSR) method to identify resonance frequencies, image depths to bedrock, and assess seismic ground vulnerability across the epicentral area of the recent earthquake swarm. Microtremor measurements were taken at 144 sites across an 18.5 km × 12.5 km study area. The HVSR analysis shows resonance frequencies as low as 1.1 Hz. Using mean shear-wave velocities obtained by Multi-Channel Analyses of Surface Waves (MASW), we find that resonance frequencies correspond to depths to bedrock of between 3 m and 56 m. There are clear relationships between the distribution of resonance frequencies, depths to bedrock, surface geology, and areas of development in recent land reclamation projects. Higher resonance frequencies characterize areas of thin sedimentary cover or hard rock sites, while relatively low resonance frequencies characterize reclaimed land or greater depths to bedrock. We quantify the seismic hazard potential across the study area using the seismic vulnerability of ground index (Kg), and observe a clear association between zones of high Kg and areas of reclaimed land. This study demonstrates the value of the HVSR technique in characterizing the subsurface and assessing seismic vulnerability in areas of reclaimed land, where it can be used as a viable and low-cost alternative to large-scale active seismic refraction or MASW measurements. The results can also be used to inform and guide urban planning projects. [ABSTRACT FROM AUTHOR]

The substrate effects on aperture resonance have been widely studied because the resonance peak position is key for sensing, communications, and field enhancement applications. So far, the theoretical works have focused on the lossless infinite substrate case, which only explains the resonance peak redshift by the substrate index. The loss effect has not been investigated yet because lossy infinite substrate significantly reduces the aperture transmission. Therefore, this work studied the loss effect on aperture resonance via an analytic model of the transmission though slot antennas on a finite substrate. When the substrate thickness was very thin compared to the wavelength, the transmittance remained high even for a large imaginary part of the refractive index; furthermore, the developed model predicted a strong blueshift when this imaginary part exceeds the real part. Besides, the zero of the imaginary part of the coupling strength was crucial in determining the resonance frequency for both infinite and finite substrates. Thus, this study can contribute to the material characterization, label-free detection, and efficient design of active metamaterials. [ABSTRACT FROM AUTHOR]

The aerodynamic performance of oscillating piezoelectric fans has been the focus of many research studies due to their potential as active cooling mechanisms for thermal management applications. These studies have typically focused on commercially available fans with flexible beams that are made to oscillate by tuning the alternating input voltages to the beam's resonant frequency. Geometric variables such as fan height and length have previously been investigated; however, fan thickness has remained a fixed geometric constraint ( O ∼ 0.1 mm) to allow feasible resonant frequencies to be achieved. This study investigates the influence of beam thickness on the flow field generated by an oscillating beam. The beam in this study is a rigid cantilever that is mechanically oscillated at a fixed amplitude and frequency thereby obviating the requirement to operate at resonance. Thicknesses of 1 and 3.7 mm are considered. A custom-designed particle-image velocity (PIV) facility was used to capture the induced phase-locked and time-averaged flow fields in two planes. The beams were noted to produce markedly different wakes within the oscillation plane. The 1-mm beam induced two distinct diverging jets—consistent with much of the literature on piezoelectric fans. In comparison, the 3.7-mm beam created two strong lateral wake regions with minimal fluid disturbance downstream of the beam tip. Out-of-plane measurements, as well as numerical models, revealed that fluid separation from the 3.7-mm beam is inhibited due to the more dominant influence of viscous friction on the larger, upper and lower surfaces of the rigid structure. The numerical analysis also revealed the significant influence of shed, counter-rotating vortex pairs on the pressure fields around the beam structures during the subsequent half-stroke. The results of this work may inform the design of oscillating fans for use in thermal management applications, as well as contribute to the literature on the complex phenomenon of flapping wing flight. [ABSTRACT FROM AUTHOR]

Small cantilevers with a megahertz-order resonance frequency provide excellent sensitivity and speed in liquid-environment atomic force microscopy (AFM). However, stable and accurate oscillation control of a small cantilever requires the photothermal excitation, which has hindered their applications to the studies on photo-sensitive materials. Here, we develop a magnetic excitation system with a bandwidth wider than 4 MHz, enabling a light-free excitation of small cantilevers. In the system, a cantilever with a magnetic bead is driven by a magnetic field generated by a coil. In the coil driver, a differentiation circuit is used for compensating the frequency dependence of the coil impedance and keeping the current constant. By implementing several differentiation circuits with different frequency ranges, we enable to drive various cantilevers having different resonance frequencies with sufficient excitation efficiency. In contrast to the conventional coil driver with a closed-loop circuit, the developed one consists of an open-loop circuit and hence can be stably operated regardless of the coil design. With the developed system, atomic-resolution imaging of mica in liquid using a small cantilever with a megahertz-order resonance frequency is demonstrated. This development should lead to the future applications of AFM with small cantilevers to the studies on various photo-sensitive materials and phenomena. [ABSTRACT FROM AUTHOR]

Background: In dental implantology, the development of stability over time is a well-investigated topic. In case of orthodontic mini-implants, quantitative data for long-term stability is not available yet. This study aims to clinically investigate the long-term stability of mini-implants inserted in the midsagittal suture of the anterior palate. Moreover, the influence of the length of implants was elucidated. The stability of 2 × 9 and 2 × 11 mm mini-implants after orthodontic treatment (9 mm, 2.84 years ± 1.25 years; 11 mm, 3.17 years ± 0.96 years) was assessed by resonance frequency analysis (RFA). The obtained long-term pieces of data were compared with each other (9 mm vs 11 mm), as well as with the data from the matched early stability groups, to assess the initial and early secondary stability after the insertion from previous clinical trials. Results: For both lengths, the long-term stability (2 × 9 mm, 25.12 ± 7.11, n = 21; 2 × 11 mm, 24.39 ± 5.82, n = 18) was significantly lower than primary stability (2 × 9 mm, 36.14 ± 6.08, n = 19; 2 × 11 mm, 33.35 ± 3.53, n = 20). The differences within the groups disappeared over the initial healing period: after 4 weeks for the 2 × 9 mm implants and after 2 weeks for the 2 × 11 mm implants. Also, the 2 × 9 mm and 2 × 11 mm implants showed comparable long-term stability values. Conclusion: The stability of midpalatal mini-implants does not change in the long term after the initial healing period. Moreover, 2 × 9 mm mini-implants seem to be appropriate for orthodontic anchorage, as the stability of 2 × 11 mm implants is not higher. Therefore, owing to lower invasiveness, 2 × 9 mm implants should be preferred. [ABSTRACT FROM AUTHOR]

To understand and control intracranial pressure (ICP) is required for treatments in various clinical situations. To establish non-invasive ICP prediction method, we focused on the natural resonance frequency (NRF) of the brain. The ICP value, pulse waveform of intracranial pressure (PWICP) and cervical carotid pulse waveform (CCPW) were simultaneously collected from patients who underwent neurosurgical treatment. A total of 43 data were obtained from 27 patients. The total measured time was 29,653 seconds and the measured mean ICP value in each data ranged from 3.82 to 69.39 (mean 25.9) hPa. Respiratory synchronized cardiac pulses were selected and following CCPW and PWICP were collected. The transfer characteristics from collected CCPW to PWICP were calculated. The initial negative peak was judged as the NRF of the brain. The relationship between the ICP value and the NRF of the brain was presented on the quadratic functions graph (ICP = 0.0329(NRF)2 + 0.0842NRF; R2 = 0.9952). It means that the individual NRF only depends on their ICP value. The ICP value will be predicted by checking NRF of the brain from somewhere. [ABSTRACT FROM AUTHOR]

The elementary fractional-order models are the extension of first and second order models which have been widely used in various engineering fields. Some important properties of commensurate or a few particular kinds of non-commensurate elementary fractional-order transfer functions have already been discussed in the existing studies. However, most of them are only available for one particular kind elementary fractional-order system. In this paper, the stability and resonance analysis of a general kind non-commensurate elementary fractional-order system is presented. The commensurate-order restriction is fully released. Firstly, based on Nyquist's Theorem, the stability conditions are explored in details under different conditions, namely different combinations of pseudo-damping (ζ) factor values and order parameters. Then, resonance conditions are established in terms of frequency behaviors. At last, an example is given to show the stable and resonant regions of the studied systems. [ABSTRACT FROM AUTHOR]

In this article, we present a magnetically–tunable quad–band filter with high tunability in the frequency range of 2.1–3.9 GHz. A multi–band filter with four stop–bands comprises of a microstrip line coupled to four frequency–selective split–ring resonators (SRRs). We achieve tuning of individual frequency bands using magnetic reed switches connected in between the capacitive gaps of each split–ring resonator. Application of magnetic field tunes this capacitance affecting its resonance frequency. The measured reflection spectrum of the proposed device matches well with the simulation results. The results show more than 25% tunability for each of the four bands with bandwidth values in the range of 30–70 MHz with over 100% overall tunability in the 2.1–3.9 GHz frequency spectrum. [ABSTRACT FROM AUTHOR]

Background: There is disagreement about the optimal torque for tightening smartpegs for resonance frequency analysis (RFA). Subjective finger pressure during hand tightening could affect the reliability of the resulting values. The aim of the current study was therefore to assess whether or not the insertion torque of a smartpeg magnetic device influences the implant stability quotient (ISQ) value during RFA. Methods: Thirty self-tapping screw implants (XiVE S, Dentsply Sirona Implants, Bensheim, Germany) with a diameter of 3.8 mm and a length of 11 mm were inserted in three cow ribs with a bone quality of D1. The RFA value of each implant was measured (Ostell, FA W&H Dentalwerk, Bürmoos, Austria) in two orthogonal directions (mesial and buccal) after tightening the corresponding smartpeg type 45 with a mechanically defined value of 5 Ncm (Meg Torq device, Megagen, Daegu, South Korea) (test). Additionally, 4 different examiners measured the RFA after hand tightening the smartpegs, and the results were compared (control). Insertion torque values were determined by measuring the unscrew torque of hand seated smartpegs (Tohnichi Manufacturing Co. Ltd, Tokyo, Japan). Results: The ISQ values varied from 2 to 11 Ncm by hand tightening and from 2 to 6 Ncm by machine tightening. The comparison of hand and machine tightening of smartpegs displayed only minor differences in the mean ISQ values with low standard deviations (mesial 79.76 ± 2,11, buccal 77.98 ± 2,) and no statistical difference (mesial p = 0,343 and buccal p = 0,890). Conclusions: Manual tightening of smartpeg transducers allows for an objective and reliable determination of ISQ values during RFA. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to evaluate the biomechanical behavior of the interface formed between bone and implants with machined surfaces (MS) and those modified by Al2O3 sandblasting and acid etching (SBAS). Materials and methods: Before surgery, topographic characterization was performed by SEM-EDX and by mean roughness measurements. Ten Albinus rabbits received randomly 20 Ti-6Al-4V implants on its right and left tibiae, with one implant placed in each tibia. After implant insertion, the implant stability quotient (ISQ) was measured by means of resonance frequency analysis (RFA). After 3 and 6 weeks, the ISQ was again measured, followed by torque removal measurements. Analysis of variance and Tukey tests were used to analyze the data. The surface of the implants removed was evaluated by SEM-EDX. Immunohistochemical analysis of osteopontin (OPN) and osteocalcin (OC) protein was performed in bone tissue. Results: The topographic characterization showed differences between the analyzed surfaces, and the mean roughness values of SBAS group were statistically higher than MS. Overall, higher statistically significant ISQ values were observed in the SBAS group compared to the MS group (p = 0.012). The intra-group comparison of ISQ values in the SBAS group showed statistically significant differences between 0 and 3 weeks (p = 0.032) and 0 and 6 weeks (p = 0.003). The torque removal measurements of group SBAS were statistically higher when compared with the torque removal measurements of group MS in the time intervals of 3 weeks (p = 0.002) and 6 weeks (p < 0.001). SEM-EDX of the implant surfaces removed in SBAS group showed greater bone tissue covering and mean values atomic in percentage of Ca, P, and O statistically superior (p < 0.05) than MS group. Immunohistochemical reactions showed intense OC immunolabeling at 6 weeks postoperative for SBAS group. Conclusions: The topographical modifications made in group SBAS allowed a better mechanical interlocking between the implant and bone tissue. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of photobiomodulation (PBM) on the stability and displacement of orthodontic mini-implants (MIs) submitted to loading. Forty-eight and 35 mini-implants (1.5 × 8 × 1 mm) were assessed for stability and displacement, respectively (19 patients). MIs were allocated according to the intervention in 1—PBM + immediate loading (IL), 2—PBM + delayed loading (DL) (four weeks after implantation), 3—IL only, and 4—DL only. PBM (Therapy XT, DCM) was implemented using a red emission (660 nm, 4 J/cm2, 0.1 W, 20 s) immediately after implantation (day 0) and infrared emissions (808 nm; 8 J/cm2, 0.1 W, 40 s) in the following appointments every 48–72 h during two weeks (days 2, 4, 7, 9, 11, and 14). Loading of 150 gF was applied during three months for all MIs. The stability was assessed by resonance frequency analysis (Osstell ISQ), and images from Cone beam computed tomography were evaluated to determine the amount of the displacement of the MI's head. MIs from the PBM groups presented lower loss of stability (P = 0.0372). When the analysis considered the loading protocol as an additional variable, group two showed the lowest loss of stability, being significantly different from groups that did not receive PBM (P = 0.0161). There was no difference between groups two and four during the period without loading (P > 0.05). DL groups presented lower loss when the effective period of loading was assessed, independently of the application of PBM (P < 0.0001). All groups showed displacement of the MIs head without significant differences (P > 0.05). DL potentiated the effect of PBM, decreasing the loss of stability. [ABSTRACT FROM AUTHOR]

Objectives: Functional tooth replacement and bone regeneration are parts of the daily practice in modern dentistry, but well-reproducible and relatively inexpensive experimental models are still missing. We aimed to develop a new small animal model to monitor osseointegration utilizing the combination of multiple evaluation protocols. Material and methods: After cutting the tail between the C4 and C5 vertebrae in Wistar rats, costume made, parallel walled, non-threaded implants were placed into the center of the tail parallel with its longitudinal axis using a surgical guide. Osseointegration of the titanium implants was followed between 4 and 16 weeks after surgery applying axial extraction force, and resonance frequency analysis as functional tests, and histomorphometry and micro-CT as structural evaluations. Results: In functional tests, we observed that both methods are suitable for the detection of the time-dependent increase in osseointegration, but the sensitivity of the pull-out technique (an approximately five times increase with rather low standard error) was much higher than that of the resonance frequency analysis. In structural evaluations, changes in the detected bone implant contact values measured by histomorphometry (yielding 1.5 times increase, with low variations of data) were more reliable than micro-CT based evaluations to screen the developments of contact between bone and implant. Conclusion: Our results provide evidence that the caudal vertebrae osseointegration model is useful for the preclinical evaluation of implant integration into the bone. Clinical relevance: The combination of the biomechanical and structural tests offers a well-reproducible small animal system that can be suitable for studying the integration of various implant materials and surface treatments. [ABSTRACT FROM AUTHOR]

In this paper, we present the design, simulation, measurement and characterization of a seven-band polarization-insensitive and wide-angle metamaterial absorber (MMA) in the microwave frequency region. The unit-cell structure of the designed MMA is composed of a single closed-meander-wire resonator structure placed over a metal ground plane by a dielectric substrate. The simulated results exhibit that the proposed MMA has high-level absorption of over 90% at seven distinct resonance frequencies, which agree reasonably with experiment. Simulated electric field distributions reveal that the observed high-level absorption mainly originates from higher-order electric resonance response. Simulated absorbance under different angles of polarization and oblique incidence indicate that the high absorption of this MMA can be kept stable for both transverse electric and transverse magnetic waves. Furthermore, the influences of geometric parameters of the unit-cell structure on absorption properties of the MMA were also studied numerically. In addition, this proposed MMA has good performances of thinner thickness, polarization-insensitive and wide-angle properties, which has many potential applications such as detection, imaging and sensing. [ABSTRACT FROM AUTHOR]

In this paper dual band Cylindrical Dielectric Resonator Antenna (CDRA) excited by conformal trapezoidal patch is successfully developed and investigated for broadband wireless applications. Rogers TMM10i (dielectric) is used for fabrication of CDRA, which have 9.8 dielectric constant (Ɛr). A 50 Ω microstrip line integrated with vertical trapezoidal flared patch is used to feed the antenna. The measured result offers wide VSWR bandwidth matching in two bands from 2.25 to 4 GHz and 4.7 to 5.7 GHz for |S11| < − 10 dB. The average peak gain is more than 3.1 dBi for a first operating band with gain flatness less than ± 2 dB and 8.3 dBi for the second operating band with gain flatness less than ± 1.5 dB. The proposed antenna covers the entire important wireless communication band i.e. Wi-Bro (2.3–2.4 GHz), Bluetooth (2.4–2.484 GHz), WLAN (2.4–2.485 GHz and 5.15–5.7 GHz), Wi-MAX (2.5–2.7 GHz and 3.4–3.6 GHz), Satellite DMB (2.605–2.655 GHz) and LTE (3.2–3.3 GHz). A comparative analysis of antenna's parameters has been examined by CST Microwave Studio and results are verified through experimental outcomes. [ABSTRACT FROM AUTHOR]

Reduced interference from nearby communication systems is an essential need in all generations of wireless communication systems. In this paper, interference is reduced by reducing the first side lobe level (FSLL) by using the concept of tapering realized with non-identical triangular elements. Resonance frequency of an Equilateral triangular microstrip antenna depends on its patch height. This property has been used effectively to realize isosceles triangular microstrip antenna with equal height, thus resonating at the same frequency. The isosceles triangular elements are designed as non-identical elements, based on its area reduction and hence gain variation, with respect to three different standard amplitude distribution functions. Six such arrays have been designed with two different inset notch feed gaps. An analysis of the non-identical elements' antenna arrays with varying inset notch feed gaps to realize tapering in the H-plane for FSLL reduction has been presented. To verify the proposed concept, one triangular patch array using eight non-identical equilateral and isosceles triangular elements designed at 6 GHz is fabricated and tested. A reasonably acceptable agreement between the simulated and measured results validates the proposed concept. [ABSTRACT FROM AUTHOR]

Magnetoelectric studies on BaTi1−xSnxO3/NiFe2O4 (x = 0.07, 0.08, 0.09 and 0.10) lead-free bilayer laminated composites were investigated at 1 kHz and resonance frequencies. The pure phase formation of BaTi1−xSnxO3 and NiFe2O4 samples was confirmed by X-ray diffraction technique. The ferroelectric BaTi1−xSnxO3 layers of different compositions having large piezocoefficient were used for the ME studies. The composites displayed their maximum magnetoelectric voltage coefficient at resonance peaks related to the 1st radial mode. The thickness dependent magnetoelectric studies on composites with x = 0.08 revealed a giant magnetoelectric voltage coefficient of 24.53 V cm−1 Oe−1 at 285 kHz under bias field condition. Remarkably, a large self-biased magnetoelectric response of the order of ~ 2–5 V cm−1 Oe−1 at resonance was exhibited by the composites. The observed large and self-biased magnetoelectric response in BaTi1−xSnxO3/NiFe2O4 composites enables them to be a useful lead-free alternative for several magnetoelectric related applications. [ABSTRACT FROM AUTHOR]

The paper presents finite element simulation of a surface acoustic wave (SAW) one-port resonator with thick interdigital transducers (IDT) made of nickel metal for sensing dimethyl methylphosphonate (DMMP) gas by placing fluoroalcoholpolysiloxane (SXFA) sensing film in the space between thick IDT fingers. The absorption of DMMP gas changes density and thickness of SXFA film and affect the SAW propagation velocity, hence resonance frequency of the device. The change in resonance frequency is measured as sensor response. In this paper individual effects of change in density and thickness of SXFA film due to absorption of DMMP gas on sensor response are simulated. The results show that the change in thickness of the SXFA film placed in the space between thick IDT fingers of proposed device is dominant in sensor response and the sensitivity of the proposed device (2.1 kHz/mg/m3) is about 3.2 times greater than a conventional device using SXFA coated over the entire top surface of the device. [ABSTRACT FROM AUTHOR]

The plasmonic of BC3 nanostructure was investigated employing time-dependent density functional theory (TDDFT). What is striking is that BC3 nanostructure possesses preferable absorbance in the visible region. By changing the size of the nanostructure, the resonance peak position of the absorption spectrum can be effectively regulated. Moreover, when excitation direction along the armchair-edge direction, the absorption spectra are clearly stronger in the low-energy zone respect to the impulse excitation polarizes in the zigzag-edge direction. In addition, with the change of layer spacing and number of layers, the resonance frequency and resonance absorption peak intensity of plasmonic can be effectively controlled. The remarkable optical properties of BC3 nanostructure suggest potential application of the system in solar cells and photolysis water devices. [ABSTRACT FROM AUTHOR]