ABSTRACT
Planejamento pré-operatório de correção de deformidades supramaleolares através de impressão 3DRELATO DE CASOModelos impressos em 3D têm sido explorados profundamente no campo médico, destacando-se como importante ferramenta de auxílio para planejamento cirúrgico. Os autores apresentam relato de caso de um paciente, com artrose pós-traumática do tornozelo direito, submetido a osteotomia supramaleolar, em cunha de fechamento medial. Esta cirurgia foi realizada após planejamento operatório por impressão 3D, o que pode demonstrar reprodutibilidade deste método. (AU)
3D printed models have been explored deeply in the medical field, standing out as an important aid tool for surgical planning. The authors present a case report of a patient with post-traumatic arthrosis of the right ankle, who underwent supramaleolar osteotomy, using a medial closure wedge. This surgery was performed after operative planning by 3D printing, which can demonstrate the reproducibility of this method. (AU)
Subject(s)
Humans , Osteoarthritis , Osteotomy , Surgical Procedures, Operative , Congenital Abnormalities , Planning , Printing, Three-DimensionalABSTRACT
The levitation of samples in an acoustic field has been of interest in the preparation and study of amorphous solid dispersions (ASD). Here, niclosamide-polymer solutions were levitated in a multi-emitter single-axis acoustic levitator and analyzed for 10 min at a High-resolution synchrotron X-ray powder diffraction beamline. This assembly enabled high-quality and fast time-resolved measurements with microliter sample size and measurement of solvent evaporation and recrystallization of niclosamide (NCL). Polymers HPMCP-55S, HPMCP-50, HPMCP-55, Klucel®, and poloxamers were not able to form amorphous dispersions with NCL. Plasdone® and Soluplus® demonstrated excellent properties to form NCL amorphous dispersions, with the last showing superior solubility enhancement. Furthermore, this fast levitation polymer screening showed good agreement with results obtained by conventional solvent evaporation screening evaluated for five days in a stability study, carried out at 40 °C/75% RH. The study showed that acoustic levitation and high-resolution synchrotron combination opens up a new horizon with great potential for accelerating ASD formulation screening and analysis.
Subject(s)
Niclosamide , Synchrotrons , Acoustics , Chemistry, Pharmaceutical , Powders , Solubility , X-Ray Diffraction , X-RaysABSTRACT
Separation and sorting of biological entities (viruses, bacteria, and cells) is a critical step in any microfluidic lab-on-a-chip device. Acoustofluidics platforms have demonstrated their ability to use physical characteristics of cells to perform label-free separation. Bandpass-type sorting methods of medium-sized entities from a mixture have been presented using acoustic techniques; however, they require multiple transducers, lack support for various target populations, can be sensitive to flow variations, or have not been verified for continuous flow sorting of biological cells. To our knowledge, this paper presents the first acoustic bandpass method that overcomes all these limitations and presents an inherently reconfigurable technique with a single transducer pair for stable continuous flow sorting of blood cells. The sorting method is first demonstrated for polystyrene particles of sizes 6, 10, and 14.5 µm in diameter with measured purity and efficiency coefficients above 75 ± 6% and 85 ± 9%, respectively. The sorting strategy was further validated in the separation of red blood cells from white blood cells and 1 µm polystyrene particles with 78 ± 8% efficiency and 74 ± 6% purity, respectively, at a flow rate of at least 1 µl/min, enabling to process finger prick blood samples within minutes.
ABSTRACT
BACKGROUND: Cemented primary total hip arthroplasty (THA) associated with acetabular reconstruction (AR) involving impacted bone grafting has been employed successfully in the revision of cavitary defects but the results are reportedly less predictable for segmental defects. The objective of the study is to evaluate the clinical and radiographic results of patients who had presented cavitary, segmental, and combined acetabular defects and received THA/AR involving impacted morselized cancellous bone autografts followed by rigorous postoperative management. METHODS: Clinical outcomes were assessed retrospectively of 154 patients who had been submitted to 169 THA/AR procedures performed by a single surgeon over a 15-year period. The Harris Hip Score system was applied to 103 patients, and the degree of acetabular migration was determined from radiograph images of 91 AR procedures, of which 40 were segmental/combined and 51 were cavitary reconstructions. RESULTS: The frequency of aseptic acetabular loosening was 3% while that of thromboembolic events was 4.1%. According to Harris Hip Score, 87.4% of outcomes were classified as excellent/good after an average follow-up period of 6.4 years irrespective of the type of acetabular defect. Horizontal and/or vertical acetabular migrations and changes in angular tilt were observed in all ARs, although the minor movements detected did not undermine the structural stability of the reconstructions or the functional capacity of patients. CONCLUSION: The described THA/AR technique can be used effectively in the reconstruction of segmental/combined and cavitary acetabular defects. The success of the technique as applied to segmental/combined defects was attributed in part to the rigorous rehabilitation protocol with temporary postoperative weight-bearing restriction.
Subject(s)
Arthroplasty, Replacement, Hip , Hip Prosthesis , Acetabulum/diagnostic imaging , Acetabulum/surgery , Arthroplasty, Replacement, Hip/adverse effects , Bone Transplantation , Follow-Up Studies , Humans , Prosthesis Failure , Reoperation , Retrospective Studies , Treatment OutcomeABSTRACT
BACKGROUND: Shoulder arthroscopy can be performed with the patient in the lateral decubitus or beach-chair position, but in both cases, glenohumeral (GH) joint spaces must be increased to improve visualization and allow access of the optical instrument. The aim of this study was to determine the effects of limb setup and longitudinal traction on the opening of the GH space with patients placed in the beach-chair (dorsal decubitus) position. METHODS: GH spaces at 3 test points corresponding to the anatomic locations of Bankart lesions were determined indirectly from radiographic images obtained from 67 patients presenting shoulder pathology with an indication for arthroscopic surgery. Measurements were made with the operative limb in neutral rotation and positioned in relation to the coronal plane in adduction, 45° of abduction, or adduction with an axillary spacer, in each case with and without longitudinal traction. RESULTS: GH spaces were optimized at 2 of 3 test points when the operative limb was positioned in adduction or neutral rotation and manual longitudinal traction was applied with or without a polystyrene spacer placed under the axilla, but use of the spacer was essential to maximize the GH space at all 3 locations. In contrast, 45° of abduction proved to be the least appropriate position because it afforded the smallest GH space values with or without traction. CONCLUSION: Appropriate positioning of the patient on the operating table is a critical aspect of shoulder arthroscopy. Radiographic images revealed that adducted upper-limb traction with the use of an axillary spacer in patients in the beach-chair position generates a significant increase in the GH space in the lower half of the glenoid cavity, thereby facilitating visualization and access of the optical equipment to the GH compartments.
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RESUMEN Introducción: El ejercicio físico genera beneficios para la salud, pero en el caso de los atletas el entrenamiento deportivo intenso desarrolla cambios morfológicos y fisiológicos en el corazón. Muchos de estos cambios, denominados «normales o fisiológicos¼, y otros hallazgos «anormales o patológicos¼ -que sugieran la existencia de una enfermedad cardiovascular subyacente- pueden ser detectados con la realización de un electrocardiograma. Objetivos: Identificar los trastornos electrocardiográficos presentes en jóvenes atletas de alto rendimiento de un club deportivo de fútbol. Método: Se estudiaron 40 atletas del género masculino en el período de enero a junio de 2019. Los deportistas fueron evaluados mediante interrogatorio, examen físico y electrocardiograma en reposo. Resultados: Fueron detectados múltiples hallazgos electrocardiográficos normales, según los criterios internacionales para su interpretación en deportistas. La bradicardia sinusal (60%) fue el más frecuente. La aparición aislada de desviación del eje eléctrico hacia la derecha (> 120°) y el bloqueo completo de rama derecha, resultaron los únicos hallazgos limítrofes encontrados. La presencia de ondas T invertidas (10%), trastornos de conducción intraventricular (7,5%) y ondas Q anómalas (5%) fueron los hallazgos patológicos que con mayor frecuencia se detectaron. Conclusiones: El electrocardiograma de doce derivaciones constituye un estudio importante para la detección de hallazgos electrocardiográficos fisiológicos relacionados con el entrenamiento deportivo en atletas de alto rendimiento, así como de alteraciones anormales o patológicas que sugieran la existencia de enfermedad cardiovascular y constituyan un factor de riesgo desencadenante de muerte súbita de origen cardíaco.
ABSTRACT Introduction: Physical exercise is extremely beneficial to health; but in the case of athletes, intense sports training develops morphological and physiological changes in the heart. Many of these changes, called "normal or physiological", and other "abnormal or pathological" findings -which could suggest the presence of underlying cardiovascular disease- can be detected by an electrocardiogram. Objectives: To identify electrocardiographic disorders present in young high-performance athletes of a soccer club. Method: Forty male athletes were studied in the period January to June 2019. The athletes were evaluated by questioning, physical examination and electrocardiogram at rest. Results: A number of normal electrocardiographic findings -according to the international criteria for electrocardiographic interpretation in athletes- were found. Sinus bradycardia was the most frequent (60%). The isolated appearance of right axis deviation (>120°) and complete right bundle branch block were the only borderline findings. The presence of inverted T waves (10%), intraventricular conduction disorders (7.5%) and anomalous Q waves (5%) were the most frequent pathological findings. Conclusions: The twelve-lead electrocardiogram remains an important means of detecting physiological electrocardiographic findings related to sports training in high-performance athletes, as well as abnormal or pathological alterations that may be suggestive of cardiovascular disease, in addition to being triggering risk factors for sudden cardiac death.
Subject(s)
Exercise , Cause of Death , Death, Sudden, Cardiac , ElectrocardiographyABSTRACT
Two numerical methods based on the Finite Element Method are presented for calculating the secondary acoustic radiation force between interacting spherical particles. The first model only considers the acoustic waves scattering off a single particle, while the second model includes re-scattering effects between the two interacting spheres. The 2D axisymmetric simplified model combines the Gor'kov potential approach with acoustic simulations to find the interacting forces between two small compressible spheres in an inviscid fluid. The second model is based on 3D simulations of the acoustic field and uses the tensor integral method for direct calculation of the force. The results obtained by both models are compared with analytical equations, showing good agreement between them. The 2D and 3D models take, respectively, seconds and tens of seconds to achieve a convergence error of less than 1%. In comparison with previous models, the numerical methods presented herein can be easily implemented in commercial Finite Element software packages, where surface integrals are available, making it a suitable tool for investigating interparticle forces in acoustic manipulation devices.
ABSTRACT
Tissue-nonspecific alkaline phosphatase (TNAP) is a key enzyme in the biomineralization process as it produces phosphate from a number of phospho-substrates stimulating mineralization while it also inactivates inorganic pyrophosphate, a potent mineralization inhibitor. We have previously reported on the reconstitution of TNAP on Langmuir monolayers as well as proteoliposomes. In the present study, thin films composed of dimyristoylphosphatidic acid (DMPA) were deposited on titanium supports by the Langmuir-Blodgett (LB) technique, and we determined preservation of TNAP's phosphohydrolytic activity after incorporation into the LB films. Increased mineralization was observed after exposing the supports containing the DMPA:TNAP LB films to solutions of phospho-substrates, thus evidencing the role of TNAP on the growth of calcium phosphates after immobilization. These coatings deposited on metallic supports can be potentially applied as osteoconductive materials, aiming at the optimization of bone-substitutes integration in vivo.
Subject(s)
Alkaline Phosphatase/metabolism , Biomimetics , Biomineralization , Enzymes, Immobilized/metabolism , Titanium/chemistry , Calcium Phosphates/chemistry , Glycerophospholipids/chemistry , Kinetics , Surface PropertiesABSTRACT
We present an acoustic levitation system that automatically injects, transports, merges and ejects liquid droplets in mid-air. The system consists of a phased array operating at 40 kHz on top of a plane reflector. The phase array generates multiple focal points at independent positions that form standing waves between the array and the reflector. In the reflector there is an inlet for a piezoelectric droplet injector which automatically inserts liquid droplets at the lower pressure nodes of the standing waves, and a hole that serves as an outlet for ejecting the processed droplets out of the system. Simulations of the acoustic radiation potential acting on the levitating droplets are in good agreement with the experiments. High-speed footage captured the functioning of the system in four fluidic operations: injection, transport, merging and ejection of liquid droplets. Having these operations integrated reliably into a single automatic system paves the way for the adoption of mid-air acoustophoretic processing in biological, chemical and pharmaceutical applications.
Subject(s)
Acoustics/instrumentation , Injections/instrumentation , Automation , HydrodynamicsABSTRACT
High efficiency isolation of cells or particles from a heterogeneous mixture is a critical processing step in lab-on-a-chip devices. Acoustic techniques offer contactless and label-free manipulation, preserve viability of biological cells, and provide versatility as the applied electrical signal can be adapted to various scenarios. Conventional acoustic separation methods use time-of-flight and achieve separation up to distances of quarter wavelength with limited separation power due to slow gradients in the force. The method proposed here allows separation by half of the wavelength and can be extended by repeating the modulation pattern and can ensure maximum force acting on the particles. In this work, we propose an optimised phase modulation scheme for particle separation in a surface acoustic wave microfluidic device. An expression for the acoustic radiation force arising from the interaction between acoustic waves in the fluid was derived. We demonstrated, for the first time, that the expression of the acoustic radiation force differs in surface acoustic wave and bulk devices, due to the presence of a geometric scaling factor. Two phase modulation schemes are investigated theoretically and experimentally. Theoretical findings were experimentally validated for different mixtures of polystyrene particles confirming that the method offers high selectivity. A Monte-Carlo simulation enabled us to assess performance in real situations, including the effects of particle size variation and non-uniform acoustic field on sorting efficiency and purity, validating the ability to separate particles with high purity and high resolution.
ABSTRACT
Levitation and manipulation of objects by sound waves have a wide range of applications in chemistry, biology, material sciences, and engineering. However, the current acoustic levitation techniques are mainly restricted to particles that are much smaller than the acoustic wavelength. In this work, it is shown that acoustic standing waves can be employed to stably levitate an object much larger than the acoustic wavelength in air. The levitation of a large slightly curved object weighting 2.3 g is demonstrated by using a device formed by two 25 kHz ultrasonic Langevin transducers connected to an aluminum plate. The sound wave emitted by the device provides a vertical acoustic radiation force to counteract gravity and a lateral restoring force that ensure horizontal stability to the levitated object. In order to understand the levitation stability, a numerical model based on the finite element method is used to determine the acoustic radiation force that acts on the object.
ABSTRACT
A linear acoustic levitation transportation system based on a ring-type vibrator is presented. The system is composed by two 21-kHz Langevin transducers connected to a ring-shaped structure formed by two semicircular sections and two flat plates. In this system, a flexural standing wave is generated along the ring structure, producing an acoustic standing wave between the vibrating ring and a plane reflector located at a distance of approximately a half wavelength from the ring. The acoustic standing wave in air has a series of pressure nodes, where small particles can be levitated and transported. The ring-type transportation system was designed and analyzed by using the finite element method. Additionally, a prototype was built and the acoustic levitation and transport of a small polystyrene particle was demonstrated.
ABSTRACT
UV-vis spectroscopy is a powerful tool to investigate surface phenomena. Surface tension measurements coupled to spectroscopic techniques can help to elucidate how the interface organization influences the electronic properties of molecules. However, appreciable sample volumes are usually necessary to achieve strong signals during conduction of experiments. This study reports on the simultaneous acquisition of surface tension data and UV-vis spectra by axisymmetric drop shape analysis (ADSA) coupled to diffuse reflectance (DRUV) spectrophotometry using a pendant microliter-drop that requires small sample volumes and low analyte concentrations. Three example systems gave evidence of the applicability of this technique: (a) disaggregation of an organic dye driven by surfactant as a function of the surface tension and alterations in the UV-vis spectra, (b) activity of a glycosylphosphatidylinositol anchored enzyme estimated from formation of a colored product, and (c) interaction between this enzyme and biomimetic membrane systems consisting of dipalmitoylphosphaditylcholine and cholestenone. Apart from using smaller sample volume, this coupled technique allowed to investigate interfacial organization in the light of electronic spectra obtained in loco within a shorter acquisition time. This procedure provided precise interfacial information about static and dynamic systems. This has been the first study describing the kinetic activity of an enzyme in the presence of phospholipid monolayers through simultaneous determination of the surface tension and UV-vis spectra.
ABSTRACT
This paper presents a contactless, acoustic technique to manipulate and sort particles of varying size in both liquid and air media. An acoustic standing wave is generated by the superposition of counterpropagating waves emitted by two opposing emitters. The acoustic radiation force traps the smallest particles at the pressure nodes of the acoustic standing wave. The position of the particles can be manipulated by dynamically changing the phase difference between the two emitters. By applying a dynamic acoustic field (DAF), it is demonstrated that particles can be manipulated spatially and sorted according to size. The discrimination (sorting dynamic range) capability is initially demonstrated in liquid media by separating three different sets of polystyrene particles, ranging in size from 5 to 45µm in diameter. The separation between particles was performed up to a ratio of 5/6 in diameter (20% diameter difference). Finally, the scalability of the DAF method is demonstrated by sorting expanded polystyrene particles of 2 and 5 mm diameter in air.
ABSTRACT
The spontaneous oscillation of solid spheres in a single-axis acoustic levitator is experimentally investigated by using a high speed camera to record the position of the levitated sphere as a function of time. The oscillations in the axial and radial directions are systematically studied by changing the sphere density and the acoustic pressure amplitude. In order to interpret the experimental results, a simple model based on a spring-mass system is applied in the analysis of the sphere oscillatory behavior. This model requires the knowledge of the acoustic pressure distribution, which was obtained numerically by using a linear finite element method (FEM). Additionally, the linear acoustic pressure distribution obtained by FEM was compared with that measured with a laser Doppler vibrometer. The comparison between numerical and experimental pressure distributions shows good agreement for low values of pressure amplitude. When the pressure amplitude is increased, the acoustic pressure distribution becomes nonlinear, producing harmonics of the fundamental frequency. The experimental results of the spheres oscillations for low pressure amplitudes are consistent with the results predicted by the simple model based on a spring-mass system.
ABSTRACT
The nonlinear behavior of a 20.3 kHz single-axis acoustic levitator formed by a Langevin transducer with a concave radiating surface and a concave reflector is experimentally investigated. In this study, a laser Doppler vibrometer is applied to measure the nonlinear sound field in the air gap between the transducer and the reflector. Additionally, an electronic balance is used in the measurement of the acoustic radiation force on the reflector as a function of the distance between the transducer and the reflector. The experimental results show some effects that cannot be described by the linear acoustic theory, such as the jump phenomenon, harmonic generation, and the hysteresis effect. The influence of these nonlinear effects on the acoustic levitation of small particles is discussed.
ABSTRACT
OBJECTIVES: To compare the minimum charge to elicit a seizure using 2 different pulse widths, the brief pulse (0.5 milliseconds [ms]) and the ultrabrief pulse (0.3 ms). METHODS: We compared retrospectively the last 30 patients in our ECT unit whose seizure thresholds were titrated using a pulse width of 0.5 ms to the last 30 patients whose seizure thresholds were titrated using a pulse width of 0.3 ms. The former were regular clinical patients, and the latter were participating in a clinical trial on the use of ultrabrief pulse treatment. All titrations were performed with right unilateral electrode positioning. Most patients continued to use psychotropic medications. RESULTS: Initial seizure threshold (as measured in millicoulombs [mC]) for the brief pulse group (0.5 ms) was 16 (n = 1); 32 (n = 21), and 64 (n = 8); whereas for the ultrabrief pulse group (0.3 ms), it was 9.2 (n = 3), 38.4 (n = 21), 19.2 (n = 3), 76.8 (n = 2), and 307.2 (n = 1). Excluding the outlier, there was no statistical difference between mean seizure thresholds. CONCLUSIONS: If we exclude the outlier from the ultrabrief group (seizure threshold [ST], 307 mC), we can observe that most of the patients in both groups had an ST between 30 and 40 mC. No patient in the brief pulse group showed a lower ST than 16 mC, probably because this was the first step of titration for this group. The data suggest that the difference between 0.3 and 0.5 ms may not be big, although randomized prospective studies with a more precise and similar steps used for titration are needed. Clinical efficacy was not compared in the present study.
Subject(s)
Electroconvulsive Therapy/methods , Functional Laterality/physiology , Adult , Aging/physiology , Electroconvulsive Therapy/instrumentation , Electrodes , Electroencephalography , Female , Humans , Male , Middle Aged , Psychotropic Drugs/adverse effects , Psychotropic Drugs/therapeutic use , Retrospective Studies , Seizures/physiopathology , Sex Characteristics , Treatment OutcomeABSTRACT
BACKGROUND: Multidirectionally unstable supracondylar fracture of the distal humerus presents with severe instability in both flexion and extension. Closed reduction and percutaneous fixation is challenging and may not be obtained by the traditional reduction maneuver. METHODS: We retrospectively evaluated 8 children (4 boys and 4 girls) with a mean age at presentation of 7.6 years (range, 5.3 to 10.9 y) who underwent closed reduction and percutaneous fixation using a joystick technique for the treatment of multidirectionally unstable supracondylar fractures. Clinical and functional results were assessed by the system described by Flynn. Radiographs at last follow-up were compared with those taken immediate after pinning as well as with normal contralateral elbow radiographs at final follow-up. RESULTS: After an average follow-up of 14.5 months (range, 12 to 24 mo), there was no difference between the injured upper extremity and the contralateral side according to cosmetic, functional, and radiographic evaluation. There was no complication such as pin-site infection, loss of fixation, malunion, cubitus varus, iatrogenic nerve injury, or need for further surgery. CONCLUSIONS: The joystick technique is a safe and effective method that can avoid aggressive and frustrating attempts of closed reduction and further open reduction of multidirectionally unstable supracondylar fractures of the humerus in children. LEVEL OF EVIDENCE: Level IV-case series.
Subject(s)
Fracture Fixation, Intramedullary/methods , Humeral Fractures/surgery , Child , Child, Preschool , Elbow Joint , Female , Humans , Male , Retrospective StudiesABSTRACT
The use of acoustic levitation in the fields of analytical chemistry and in the containerless processing of materials requires a good stability of the levitated particle. However, spontaneous oscillations and rotation of the levitated particle have been reported in literature, which can reduce the applicability of the acoustic levitation technique. Aiming to reduce the particle oscillations, this paper presents the analysis of the particle stability in a new acoustic levitator device. The new acoustic levitator consists of a piezoelectric transducer with a concave radiating surface and a concave reflector. The analysis is conducted by determining numerically the axial and lateral forces that act on the levitated object and by measuring the oscillations of a sphere particle by a laser Doppler vibrometer. It is shown that the new levitator design allows to increase the lateral forces and reduce significantly the lateral oscillations of the levitated object.
ABSTRACT
A matrix method is presented for simulating acoustic levitators. A typical acoustic levitator consists of an ultrasonic transducer and a reflector. The matrix method is used to determine the potential for acoustic radiation force that acts on a small sphere in the standing wave field produced by the levitator. The method is based on the Rayleigh integral and it takes into account the multiple reflections that occur between the transducer and the reflector. The potential for acoustic radiation force obtained by the matrix method is validated by comparing the matrix method results with those obtained by the finite element method when using an axisymmetric model of a single-axis acoustic levitator. After validation, the method is applied in the simulation of a noncontact manipulation system consisting of two 37.9-kHz Langevin-type transducers and a plane reflector. The manipulation system allows control of the horizontal position of a small levitated sphere from -6 mm to 6 mm, which is done by changing the phase difference between the two transducers. The horizontal position of the sphere predicted by the matrix method agrees with the horizontal positions measured experimentally with a charge-coupled device camera. The main advantage of the matrix method is that it allows simulation of non-symmetric acoustic levitators without requiring much computational effort.
