An ultrasound-based ensemble machine learning model for the preoperative classification of pleomorphic adenoma and Warthin tumor in the parotid gland.

OBJECTIVES: The preoperative classification of pleomorphic adenomas (PMA) and Warthin tumors (WT) in the parotid gland plays an essential role in determining therapeutic strategies. This study aims to develop and validate an ultrasound-based ensemble machine learning (USEML) model, employing nonradiative and noninvasive features to differentiate PMA from WT. METHODS: A total of 203 patients with histologically confirmed PMA or WT who underwent parotidectomy from two centers were enrolled. Clinical factors, ultrasound (US) features, and radiomic features were extracted to develop three types of machine learning model: clinical models, US models, and USEML models. The diagnostic performance of the USEML model, as well as that of physicians based on experience, was evaluated and validated using receiver operating characteristic (ROC) curves in internal and external validation cohorts. DeLong's test was used for comparisons of AUCs. SHAP values were also utilized to explain the classification model. RESULTS: The USEML model achieved the highest AUC of 0.891 (95% CI, 0.774-0.961), surpassing the AUCs of both the US (0.847; 95% CI, 0.720-0.932) and clinical (0.814; 95% CI, 0.682-0.908) models. The USEML model also outperformed physicians in both internal and external validation datasets (both p < 0.05). The sensitivity, specificity, negative predictive value, and positive predictive value of the USEML model and physician experience were 89.3%/75.0%, 87.5%/54.2%, 87.5%/65.6%, and 89.3%/65.0%, respectively. CONCLUSIONS: The USEML model, incorporating clinical factors, ultrasound factors, and radiomic features, demonstrated efficient performance in distinguishing PMA from WT in the parotid gland. CLINICAL RELEVANCE STATEMENT: This study developed a machine learning model for preoperative diagnosis of pleomorphic adenoma and Warthin tumor in the parotid gland based on clinical, ultrasound, and radiomic features. Furthermore, it outperformed physicians in an external validation dataset, indicating its potential for clinical application. KEY POINTS: • Differentiating pleomorphic adenoma (PMA) and Warthin tumor (WT) affects management decisions and is currently done by invasive biopsy. • Integration of US-radiomic, clinical, and ultrasound findings in a machine learning model results in improved diagnostic accuracy. • The ultrasound-based ensemble machine learning (USEML) model consistently outperforms physicians, suggesting its potential applicability in clinical settings.

Optically Controlled Nano-Transducers Based on Cleaved Superlattices for Monitoring Gigahertz Surface Acoustic Vibrations.

Surface acoustic waves (SAWs) convey energy at subwavelength depths along surfaces. Using interdigital transducers (IDTs) and opto-acousto-optic transducers (OAOTs), researchers have harnessed coherent SAWs with nanosecond periods and micrometer localization depth for various applications. These applications include the sensing of small amount of materials deposited on surfaces, assessing surface roughness and defects, signal processing, light manipulation, charge carrier and exciton transportation, and the study of fundamental interactions with thermal phonons, photons, magnons, and more. However, the utilization of cutting-edge OAOTs produced through surface nanopatterning techniques has set the upper limit for coherent SAW frequencies below 100 GHz, constrained by factors such as the quality and pitch of the surface nanopattern, not to mention the electronic bandwidth limitations of the IDTs. In this context, unconventional optically controlled nanotransducers based on cleaved superlattices (SLs) are here presented as an alternative solution. To demonstrate their viability, we conducted proof-of-concept experiments using ultrafast lasers in a pump-probe configuration on SLs made of alternating AlxGa1-xAs and AlyGa1-yAs layers with approximately 70 nm periodicity and cleaved along their growth direction to produce a periodic nanostructured surface. The acoustic vibrations, generated and detected by laser beams incident on the cleaved surface, span a range from 40 to 70 GHz, corresponding to the generalized surface Rayleigh mode and bulk modes within the dispersion relation. This exploration shows that, in addition to SAWs, cleaved SLs offer the potential to observe surface-skimming longitudinal and transverse acoustic waves at GHz frequencies. This proof-of-concept demonstration below 100 GHz in nanoacoustics using such an unconventional platform might be useful for realizing sub-THz to THz coherent surface acoustic vibrations in the future, as SLs can be epitaxially grown with atomic-scale layer width and quality.

Preparation of diblock copolymer nano-assemblies by ultrasonics assisted ethanol-phase polymerization-induced self-assembly.

Assemblies are widely used in biomedicine, batteries, functional coatings, Pickering emulsifiers, hydrogels, and luminescent materials. Polymerization-induced self-assembly (PISA) is a method for efficiently preparing particles, mainly initiated thermally. However, thermally initiated PISA usually requires a significant amount of time and energy. Here, we demonstrate the preparation of nano-assemblies with controllable morphologies and size using ultrasound (20 kHz) assisted ethanol-phase RAFT-PISA in three hours. Using poly (N, N-dimethylaminoethyl methacrylate) as the macromolecular reversible addition-fragmentation chain transfer agent (PDMA-CTA) to control the nucleating monomer benzyl methacrylate (BzMA), we obtained nano-assemblies with different morphologies. With the length of hydrophobic PBzMA block growth, the morphologies of the assemblies at 15 wt% solid content changed from spheres to vesicles, and finally to lamellae; the morphologies of the assemblies at 30 wt% changed from spheres micelles to short worms, then vesicles, and finally to large compound vesicles. With the same targeted degree of polymerization, nano-assemblies having a 30 wt% solid content display a more evolved morphology. The input of ultrasonic energy makes the system have higher surface free energy, results the mass fraction interval of solventphilic blocks (fhydrophilic) corresponding to the formation of spherical micelles is expanded from fhydrophilic > 45 % to fhydrophilic > 31 % under ultrasound and the fhydrophilic required to form worms, vesicles, and large composite vesicles decreases in turn. It is worth noting that the fhydrophilic interval of worms prepared by ultrasonics assisted PISA gets larger. Overall, the highly green, externally-regulatable and fast method of ultrasonics assisted PISA can be extended to vastly different diblock copolymers, for a wide range of applications.

Study of thermal effects induced by the high-frequency probing laser in nonlinear opto-acoustic frequency-mixing technique.

Photo-thermal modulation-based nonlinear opto-acoustic frequency-mixing technique is an effective method for detecting micro-cracks. When using this technique for micro-crack detection, the selection of laser source parameters is particularly crucial. Compared to traditional piezo-transducer-based mixing techniques, the characteristic of using a laser as the detection source is the presence of thermal effects. The thermal effect caused by laser irradiation on the sample surface can not only generate acoustic waves but also affect the crack state, thus influencing nonlinear signals. In this paper, an experimental setup using photo-thermal modulation-based nonlinear opto-acoustic frequency-mixing technique has been set up to investigate the thermal effects of the probe laser source. In addition, a corresponding physical model has been established to discuss the physical mechanisms revealed by the experimental results. This study provides a basis for selecting appropriate probe source parameters and scanning positions of laser sources when detecting micro-cracks using the photo-thermal modulation-based nonlinear opto-acoustic frequency-mixing technique.

Defect detection in additively manufactured AlSi10Mg and Ti6Al4V samples using laser ultrasonics and phase shift migration.

Laser ultrasonics (LU) is a non-contact and non-destructive method with a high data acquisition rate, making it a promising candidate for in-situ monitoring of defects in different additive manufacturing (AM) processes, including laser powder bed fusion (LPBF) and directed energy deposition, as well as final part inspection. In order to see the effect of various artificial defect types on an LU sub-surface reconstruction, AlSi10Mg samples with side through-holes, as well as Ti6Al4V samples with bottom blind holes and trapped powder were printed using LPBF, and then ultrasound B-scans of the samples were obtained using an LU system. The resulting scan data was processed using a custom frequency domain phase shift migration (PSM) algorithm, to reconstruct the defects and their locations. Novel ways of pre-processing the B-scan, used as an input to PSM, and taking advantage of its frequency representation, are demonstrated. Newton's method was used to find a stationary phase approximation, used to account in the frequency domain for the fixed offset emitter-receiver arrangement within the PSM calculation. The Newton's method calculation time was reduced by 33%, by using an approximation of the phase function to find an initial guess. The smallest defects that were detected using this method were in the size range between 200 to 300µm for the bottom hole defects, using an 8 ns laser pulse duration. The effect of the laser on the surface of a part being built, and the challenges and further work needed to integrate LU in a LPBF machine for in-situ inspection are discussed.

Mediation of long-pulsed ultrasound enhanced microbubble recombinant tissue plasminogen activator thrombolysis in a rat model of platelet-rich thrombus.

Background: Ultrasound (US)-enhanced microbubble (MB) therapy has been investigated as a therapeutic technique to facilitate the thrombolysis for the treatment of pericardial and microvascular obstruction. This study sought to assess the therapeutic effects of long-pulsed US-assisted MB-mediated recombinant tissue plasminogen activator (rt-PA) thrombolysis in a rat model of platelet-rich thrombus. Methods: Ferric chloride (10%) was used to induce total arterial occlusion before formation of platelet-rich thrombi. Therapeutic long-tone-burst US (1 MHz, 0.6 MPa, 1,000-µs pulse length) was used, and 2.9×109/mL of lipid MBs and 1 mg/mL of rt-PA were infused. Subsequently, 42 Sprague-Dawley (SD) male rats were randomly divided into seven groups: (I) control; (II) rt-PA; (III) high duty cycle US + MB; (IV) low duty cycle US + rt-PA; (V) high duty cycle US + rt-PA; (VI) low duty cycle US + rt-PA + MB; and (VII) high duty cycle US + rt-PA + MB. The recanalization grades were evaluated after 20 minutes' treatment. Results: Compared to the control, there was significant improvement in recanalization in the US + rt-PA groups (P=0.01 vs. control), US (low duty cycle) + rt-PA + MB (P=0.003 vs. control) and US (high duty cycle) + rt-PA + MB (P<0.001 vs. control) groups, in which recanalization was successfully achieved in all rats. Conclusions: Long-pulsed US-enhanced MB-mediated rt-PA thrombolysis offered a powerful approach in the treatment of platelet-rich thrombus.

Successful Percutaneous Ultrasonic Lithotripsy of Gallstones.

Background: Acute calculous cholecystitis is the obstruction of the cystic duct by a gallstone that leads to inflammation of the gallbladder necessitating cholecystectomy. Case Series: We present the cases of 2 patients with acute calculous cholecystitis who were deemed ineligible candidates for cholecystectomy because of their complicating medical histories. Both patients initially underwent cholecystostomy and drain placement with interventional radiology for management of acute calculous cholecystitis. Their large gallstones remained refractory to attempts at removal by electrohydraulic lithotripsy via the cholecystostomy access. The patients' gallstones were successfully removed via percutaneous ultrasonic lithotripsy during a collaborative procedure with interventional radiology and urology. Conclusion: An interdisciplinary approach using percutaneous cholecystolithotomy with rigid ultrasonic lithotripsy is an effective method for removing challenging gallstones in patients for whom traditional approaches fail.

Data-driven Identification of Parametric Governing Equations of Dynamical Systems Using the Signed Cumulative Distribution Transform.

This paper presents a novel data-driven approach to identify partial differential equation (PDE) parameters of a dynamical system. Specifically, we adopt a mathematical "transport" model for the solution of the dynamical system at specific spatial locations that allows us to accurately estimate the model parameters, including those associated with structural damage. This is accomplished by means of a newly-developed mathematical transform, the signed cumulative distribution transform (SCDT), which is shown to convert the general nonlinear parameter estimation problem into a simple linear regression. This approach has the additional practical advantage of requiring no a priori knowledge of the source of the excitation (or, alternatively, the initial conditions). By using training data, we devise a coarse regression procedure to recover different PDE parameters from the PDE solution measured at a single location. Numerical experiments show that the proposed regression procedure is capable of detecting and estimating PDE parameters with superior accuracy compared to a number of recently developed machine learning methods. Furthermore, a damage identification experiment conducted on a publicly available dataset provides strong evidence of the proposed method's effectiveness in structural health monitoring (SHM) applications. The Python implementation of the proposed system identification technique is integrated as a part of the software package PyTransKit [1].

Can Mn:PIN-PMN-PT piezocrystal replace hard piezoceramic in power ultrasonic devices?

Mn:PIN-PMN-PT piezocrystal is investigated to determine whether its enhanced energy density makes it a candidate transducer material for power ultrasonics applications. To this end, the electromechanical and vibrational characteristics of a simple configuration of a bolted Langevin transducer (BLT) and then an ultrasonic surgical device, both incorporating Mn:PIN-PMN-PT piezocrystal, are compared with the same transducer configurations incorporating a conventional hard PZT piezoceramic commonly used in high-power ultrasonic transducers. The material properties of Mn:PIN-PMN-PT are determined using a single sample characterisation technique and these are used in finite element analysis (FEA) to design and then fabricate the BLT and ultrasonic surgical device, tuned to the first and second longitudinal modes at 20 kHz respectively. FEA is similarly used for the hard PZT versions. It is found that the superior elastic compliance of Mn:PIN-PMN-PT results in a higher radial piezo-stack deformation than the hard PZT under ultrasonic excitation of the BLT. However, the resulting longitudinal displacement amplitude of the two BLTs and two ultrasonic surgical devices is found to be equal, despite the higher figure of merit (Qkeff2) of those incorporating Mn:PIN-PMN-PT. The electrical impedance is measured at increasing excitation levels to evaluate the quality factor, Q. It is found that damping in the BLT with hard PZT is negligibly affected in the excitation range considered; however, the BLT incorporating Mn:PIN-PMN-PT exhibits a large reduction in Q. These findings indicate that, for measurements in air, the advantages of the high figure of merit of the piezocrystal material are not realised in a high-power transducer due to significantly increased damping at high excitation levels. To compare the vibrational response of the two ultrasonic surgical devices, L-C electrical impedance matching was implemented to maximise the efficiency of energy transfer from the source to the transducer under load. Results suggest that similar responses occurred for the two surgical devices in cutting tests using a low strength bone mimic material. However, the Mn:PIN-PMN-PT device exhibited better performance in cutting through higher strength ex-vivo chicken femur.

Acoustic Source Localization in Composite Plates using sideband peak count - Index Technique.

In this study the Non-Linear Ultrasonic Sideband Peak Count-Index (SPC-I) technique is used as the foundation for anovel approach towards acoustic source localization (ASL) in orthotropic composite plates. The SPC-I based technique proposed here does not require the signal attenuation information or any knowledge on the time of arrival of the signal. It should be noted that since individual sensors can have varying sensitivities, the signal attenuation measured from the recorded signal amplitude is not very reliable. In addition, it is not necessary to have any prior knowledge of the mechanical properties of the composite plate material. All these are achievable by attaching 25 sensors that are well-scattered on the surface of the plate. The signals that are generated by an acoustic source are recorded by these 25 sensors. The recorded signals are then analyzed to derive the SPC-I value for each signal. The calculated SPC-I values are run through an optimization algorithm to predict the acoustic source location. Such localization is possible because the composite plate is inherently a non-linear material. Hence, as the signal travels longer distances through a composite plate, the recorded signal should show increasing level of distortion due to material non-linearity and dispersion. This phenomenon manifests itself primarily as a consequence of signal scattering and frequency modulation. Because of this, the phenomena of increasing distortion in the signal with increasing propagation distance can be exploited and utilized to predict the location of the acoustic source by solely utilizing the SPC-I values. This acoustic source localization technique is experimentally verified on a Carbon Fiber Reinforced (CFR) composite plate of dimension 500 mm x 500 mm with a thickness of 1 mm. The experimental results confirmed the feasibility of the proposed technique.

Feasibility Study for Monitoring an Ultrasonic System Using Structurally Integrated Piezoceramics.

This paper presents a new approach to monitoring ultrasonic systems using structurally integrated piezoceramics. These are integrated into the sonotrode at different points and with different orientations. The procedure for integrating the piezoceramics into the sonotrode and their performance is experimentally investigated. We examine whether the measured signal can be used to determine the optimal operating frequency of the ultrasonic system, if integrating several piezoceramics enables discernment of the current vibration shape, and if the piezoceramics can withstand the high strains caused by the vibrations in a frequency range of approximately 20-25 kHz. The signals from the piezoceramic sensors are compared to the real-time displacement at different points of the sonotrode using a 3D laser scanning vibrometer. To evaluate the performance of the sensors, different kinds of excitation of the ultrasonic system are chosen.

Solanum pseudocapsicum vs Capsicum annum; comparative phenolics profiling using green ultrasonic extraction and UHPLC analysis.

BACKGROUND: Solanum pseudocapsicum (PC) and Capsicum annum (CA) belongs to the family of Solanaceae. CA have been reported a rich source of phenolics whereas, the phenolics content of GA (gallic acid), SC (scopoletin), RA (rosmarinic acid), and RV (resveratrol) are yet to be reported for the PC-fruit. This study comparatively evaluates the phenolics profile for different parts (seeds and skin) and colors (green and red) of the PC- and CA-fruits using the green solvents of ethanol (ET), acetone (AC), water (H2O), and different combinations of these solvents. METHODOLOGY: Ultrasonics extraction (US) and UHPLC analysis were employed for phenolics evaluation. RESULTS: The USMD (method development) revealed the highest extract yield of 62 mg/100 mg for the PC-skin in ET:AC (70:30) solvent whereas, more phenolics (ppm) were observed for PC-seeds in ET:AC (50:50) solvent, particularly the SC (29.46) and GA (16.92). The UHPLCMDMV exhibited significant accuracies (100.70-114.14 %) with r2-values (0.9993-0.9997) in the linearity range of 1-200 ppm. The USMV (method validation) in PC- and CA-fruit parts and colors revealed more extract yields for the red skin part of the PC- (180.5 mg) and CA-fruit (126.2 mg). The phenolics were seen more in the green seeds of the PC-fruit (ppm); SC (276), GA (147.36), RV (28.54), and RA (23.87) followed by the green PC-skin, and red/green CA-seeds. The statistical models of mean differences, ANOVA, and Pearson's correlation showed significant differences for the PC-fruit parts (seeds and skin) and colors (red and green) vs extract yield and phenolics content (P = 0.05). CONCLUSION: PC-and CA-fruits were successfully evaluated where the seeds for the green fruits exhibited more phenolics amount.

Flatsonic Ultrasonic Tip Optimizes the Removal of Remaining Filling Material in Flattened Root Canals: A Micro-computed Tomographic Analysis.

INTRODUCTION: The aim of this study was to evaluate the effectiveness of the XP-endo Finisher R (XPFR; FKG Dentaire, La Chaux-de-Fonds, Switzerland) or the Flatsonic ultrasonic tip (Helse Ultrasonic, Santa Rosa de Viterbo, SP, Brazil) in removing remaining filling material after the retreatment of flattened root canals using micro-computed tomographic imaging. METHODS: Twenty-four flattened distal root canals of mandibular molars with a buccolingual diameter 4 or more times larger than the mesiodistal diameter were prepared with Reciproc Blue (RB) R40 (VDW GmbH, Munich, Germany) and filled using the Tagger hybrid technique. All canals were retreated with RB R40, and apical enlargement was performed with RB R50 (VDW GmbH). The specimens were randomly distributed into 2 groups: XPFR or Flatsonic (n = 12). The percentage of remaining filling material after retreatment and centralization ability was evaluated. Data were submitted to Mann-Whitney, Wilcoxon, and unpaired t tests (α = 5%). RESULTS: Greater capacity to remove remaining filling material in the entire canal and the cervical and middle thirds was observed for the Flatsonic compared with the XPFR (P < .05). However, both supplementary cleaning techniques showed a similar percentage of residual filling material in the apical third (P > .05). No difference was observed in the centralization ability between the techniques (P > .05). CONCLUSIONS: The Flatsonic promotes greater removal of remaining filling material than the XPFR in the retreatment of flattened root canals. However, both supplementary cleaning approaches were similar in the apical third. The XPFR and Flatsonic were able to maintain root canal centralization.

Finite element modelling strategy for determining directivity of thermoelastically generated laser ultrasound.

Laser ultrasound (LU) is a contactless and couplant-free remote non-destructive (NDE) technique, which uses lasers for ultrasonic generation and detection rather than conventional piezoelectric transducers. For a transducer, an important characteristic is the directivity, the angle-dependent amplitude of the ultrasonic waves generated in the material. In the non-destructive thermoelastic regime, LU source has been widely modelled as a surface force dipole. However, the directivity of LU in more complex material, where there is an increasing demand for NDE, such as carbon fibre reinforced plastic (CFRP), is yet to be understood. In the current paper, a finite element (FE) modelling methodology to obtain the directivity of LU in complex material is presented. The method is applied to a conductive isotropic material (aluminium, Al) for validation against an existing analytical solution and then applied to a heterogeneous anisotropic material (carbon-fibre reinforced plastic, CFRP). To get the directivity of a specific wave mode, the signal for that mode needs to be resolved in time from other modes at all angles. This is challenging for shear (S) waves in a small model domain due to the head wave, so a technique for suppressing the head wave is shown. The multi-physics model solves for thermal expansion, which models the laser source as a surface heat flux for the Al case, and a buried heat source for the CFRP case, according to where the energy is deposited in the material. The same ultrasound generation pattern can be obtained by using a suitable pure elastodynamic loading, which is shown to be a surface force dipole as per the validation case for Al, and a buried quadrupole for the CFRP case. The modelled directivities are scaled and fitted to experimental measurements using maximum likelihood, and the goodness of fit is discussed. For the Al case, the S wave is preferred over the longitudinal (L) wave for inspection due to greater signal amplitude. For the CFRP case, the quasi-longitudinal (qL) wave in CFRP shows a maximum amplitude directly below the source, and has a greater amplitude than the quasi-shear (qS) wave, suggesting a better choice for inspection.

Composição da gordura corporal em pacientes com doenças inflamatórias intestinais: um estudo comparativo entre dobras cutâneas e ultrassonografia / Body fat composition in patients with inflammatory bowel diseases: a comparative study between skinfolds and ultrasonography

ABSTRACT Background: Inflammatory bowel diseases (IBD) are associated with important changes in nutritional status. Objective: The aim of the study was to compare body fat composition between two anthropometric methods: skinfolds and ultrasonography, in patients with IBD. Methods: Single-center cross-sectional study with IBD patients in remission or active disease. For the agreement analysis between the body fat assessment methods, the Bland Altman method was used. Results: A total of 101 patients with IBD were included, 75 with Crohn's disease and 26 with ulcerative colitis. Approximately 56% of the patients with Crohn's disease and 65.4% of those with ulcerative colitis had a body fat composition above normal levels, with no significant difference between the diseases (P=0.63). The Bland-Altman concordance analysis showed that the methods for assessing the percentage of fat by the adipometer and ultrasound were not in full agreement (P=0.001), despite both presented good correlation (CC 0.961; P=0.000). Conclusion: The analysis of body fat percentage in patients with IBD was different between the skinfolds and ultrasound. Both methods can be used to assess the of body fat percentage of patients with IBD. However, monitoring of body fat sequentially and longitudinally should always be performed using the same method throughout the disease course. Prospective longitudinal studies are warranted to precisely define the role of these two methods of measuring body composition in patients with IBD.

RESUMO Contexto: As doenças inflamatórias intestinais (DII) estão associadas a alterações importantes no estado nutricional. Objetivo: O objetivo do estudo foi comparar a composição da gordura corporal entre dois métodos antropométricos: dobras cutâneas e ultrassonografia, em pacientes com DII. Métodos: Estudo transversal de centro único com pacientes com DII em remissão ou doença ativa. Para a análise de concordância entre os métodos de avaliação da gordura corporal foi utilizado o método de Bland-Altman. Resultados: Foram incluídos 101 pacientes com DII, 75 com doença de Crohn e 26 com colite ulcerativa. Aproximadamente 56% dos pacientes com doença de Crohn e 65,4% daqueles com colite ulcerativa apresentaram composição de gordura corporal acima dos níveis normais, sem diferença significativa entre as doenças (P=0,63). A análise de concordância de Bland-Altman mostrou que os métodos de avaliação do percentual de gordura pelo adipômetro e ultrassonografia não foram totalmente concordantes (P=0,001), apesar de ambos apresentarem boa correlação (CC 0,961; P=0,000). Conclusão: A análise do percentual de gordura corporal em pacientes com DII foi diferente entre as dobras cutâneas e a ultrassonografia. Ambos os métodos podem ser usados para avaliar o percentual de gordura corporal de pacientes com DII. Entretanto, o monitoramento da gordura corporal de forma sequencial e longitudinal deve ser sempre realizado utilizando o mesmo método durante todo o curso da doença. Estudos longitudinais prospectivos são necessários para definir com precisão o papel desses dois métodos de medição da composição corporal em pacientes com DII.

Ultrafast magnetoacoustics in Galfenol nanostructures.

Phonons and magnons are prospective information carriers to substitute the transfer of charge in nanoscale communication devices. Our ability to manipulate them at the nanoscale and with ultimate speed is examined by ultrafast acoustics and femtosecond optomagnetism, which use ultrashort laser pulses for generation and detection of the corresponding coherent excitations. Ultrafast magnetoacoustics merges these research directions and focuses on the interaction of optically generated coherent phonons and magnons. In this review, we present ultrafast magnetoacoustic experiments with nanostructures based on the alloy (Fe,Ga) known as Galfenol. We demonstrate how broad we can manipulate the magnetic response on an optical excitation by controlling the spectrum of generated coherent phonons and their interaction with magnons. Resonant phonon pumping of magnons, formation of magnon polarons, driving of a magnetization wave by a guided phonon wavepacket are demonstrated. The presented experimental results have great application potential in emerging areas of modern nanoelectronics.

Effectiveness of a new endodontic irrigation system for removing smear layer and dissolving simulated organic matter.

OBJECTIVES: The study aimed to evaluate the potential for the dissolution of organic tissue in areas of simulated complexity and cleaning of root canal walls of the new iVac® endodontic irrigation system. MATERIAL AND METHODS: Thirty mandibular premolars were evaluated by scanning electron microscopy before and after biomechanical preparation. Then, they were distributed according to the final irrigation protocol into groups with conventional irrigation, ultrasonic agitation with metallic insert (UA), and iVac® system, and new photomicrographs were obtained. For tissue dissolution analysis, glass capillaries filled with catgut were attached to the cervical and apical thirds of twenty-one prototyped upper incisors. They were weighed before and after the previously mentioned irrigation protocols. The data were statistically compared with a significance level of 5%. RESULTS: The final irrigation provided greater cleaning of the root canal walls in the cervical, middle, and apical thirds of the root canals (P < 0.05), with no statistically significant difference between UA and iVac®, regardless of the analyzed thirds. Both ultrasonic irrigation protocols dissolved a significantly greater volume than the conventional irrigation protocol (P < 0.05), with no difference between the two protocols (P < 0.05). CONCLUSIONS: The iVac® system showed root canal wall cleaning and tissue dissolution similar to UA with a metallic insert, and both were superior to conventional irrigation. CLINICAL RELEVANCE: The new irrigation system iVac is more effective than conventional irrigation and has similar root canal wall cleaning and tissue dissolution to UA.

The Management of Fractured Dental Instruments: A Case Series.

The most common problem faced by dentists during root canal therapy is instrument separation. Instrument separation leads to the inefficient biomechanical preparation of the canals, which can affect the outcome of the root canal-treated tooth. Hence, bypassing the fractured instrument or removal can be accounted as a viable choice to maintain the structural integrity of the tooth. This article illustrates a case series wherein the fractured instrument was managed successfully with the use of conservative techniques.

Ultrasonic Bone Scalpel versus Conventional Technique for Thoracolumbar Spinal Decompression: A Prospective Randomized Controlled Trial.

Objective The purpose of the present study is to compare intraoperative blood loss, operating time, laminectomy time, hospital length of stay, and complications in thoracolumbar spinal decompression using ultrasonic bone scalpels (UBSs) with conventional procedures. Methods Forty-two patients who underwent decompressive laminectomy and pedicular screw fusion with a surgical level of 1-5 levels between February 1, 2020, and June 30, 2022, in a single institution were evaluated for eligibility, and 11 were excluded due to a history of spinal surgery ( n = 3), spinal tumor ( n = 3), and spinal infection ( n = 5). A total of 31 patients were randomly divided into the UBS group ( n =15) and the conventional group ( n =16). Intraoperative blood loss, operating time, laminectomy time, hospital length of stay, and complications were recorded. Results Intraoperative blood loss and laminectomy time were significantly lower in the UBS group (656.0 ± 167.6 ml, 54.5 ± 27.4 minutes, respectively) than in the conventional group (936.9 ± 413.2 ml, 73.4 ± 28.1 minutes, respectively). Overall operation time, hospital length of stay, and complications were all similar between the groups. Conclusion The UBS is a useful instrument for procedures performed near the dura mater or other neural tissue without excessive heat or mechanical injury. This device is recommended for various spinal surgeries in addition to high-speed burrs and Kerrison rongeurs.

Time-domain Brillouin scattering theory for probe light and acoustic beams propagating at an angle and acousto-optic interaction at material interfaces.

A theory has been developed to interpret time-domain Brillouin scattering (TDBS) experiments involving coherent acoustic pulse (CAP) and light pulse beams propagating at an angle to each other. It predicts the influence of the directivity pattern of their acousto-optic interaction on TDBS signals when heterodyne detection of acoustically scattered light is in backward direction to incident light. The theory reveals relationships between the carrier frequency, amplitude and duration of acoustically induced "wave packets" in light transient reflectivity signals, and factors such as CAP duration, widths of light and sound beams, and their interaction angle. It describes the transient dynamics of these wave packets when the light and CAP encounter material interfaces, and how the light scattering by the incident CAP transforms into scattering by the reflected and transmitted CAPs. The theory suggests that single-point TDBS experiments can determine not only depth positions of buried interfaces but also their local inclinations/orientations.