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1.
World J Pediatr Congenit Heart Surg ; : 21501351241269881, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39252613

RESUMEN

Background: With significant advancements in fetal cardiac imaging, patients with complex congenital heart disease (CHD) carrying a high risk for postnatal demise are now being diagnosed earlier. We sought to assess an interdisciplinary strategy for delivering these children in an operating room (OR) adjacent to a cardiac OR for immediate surgery or stabilization. Methods: All children prenatally diagnosed with CHD at risk for immediate postnatal hemodynamic instability and cardiogenic shock who were delivered in the operating room (OR) between 2012 and 2023 in which the senior author was consulted were included. Results: Eight patients were identified. Six (75%) patients were operated on day-of-life zero, all requiring obstructed total anomalous pulmonary venous return (TAPVR) repair. Of these six patients, 2 (33%) required a simultaneous Norwood procedure, 2 (33%) required pulmonary artery unifocalization and modified Blalock-Taussig-Thomas shunt, and 2 (33%) patients had repair of obstructed mixed TAPVR. The remaining 2 patients potentially planned for immediate surgery had nonimmune hydrops fetalis and went into cardiogenic shock at 12 and 72 hours postnatally, requiring a novel Norwood procedure with left-ventricular exclusion for severe aortic/mitral valve insufficiency. The median ventilation and inpatient durations were 19 [IQR: 11-26] days and 41 [IQR: 32-128] days, respectively. Three(38%) patients required one or more in-hospital reoperations. Subsequent staged procedures included Glenn (n = 5), Fontan (n = 3), biventricular repair (n = 2), ventricular assist device placement (n = 1), and heart transplant (n = 1). Median follow-up was 5.7 [IQR:1.3-7.8] years. The five-year postoperative survival was 88% (n = 7/8). Conclusion: While children with these diagnoses have historically had poor survival, the strategy of birth in the OR adjacent to a cardiac OR where emergent surgery is planned is a potentially promising strategy with excellent clinical outcomes. However, this is a high-resource strategy whose feasibility in any program requires thoughtful assessment.

2.
Phys Chem Chem Phys ; 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39254512

RESUMEN

A good explanation of lithium-ion batteries (LIBs) needs to convincingly account for the spontaneous, energy-releasing movement of lithium ions and electrons out of the negative and into the positive electrode, the defining characteristic of working LIBs. We analyze a discharging battery with a two-phase LiFePO4/FePO4 positive electrode (cathode) from a thermodynamic perspective and show that, compared to loosely-bound lithium in the negative electrode (anode), lithium in the ionic positive electrode is more strongly bonded, moves there in an energetically downhill irreversible process, and ends up trapped in the positive electrode. Only a sufficiently high charging voltage can drive it back to the other electrode. Since the stronger bonding in the positive electrode lowers the energy by ∼320 kJ mol-1, a lot of energy is released. This explanation is quantitatively supported by an analysis of cohesive-energy differences of the electrode materials. Since electrons are only intermediates in the discharge reaction and the chemical potential of the electron cannot be measured, electrons do not need to be assigned a distinct energetic role. The incorporation of Li+ and an electron into the cathode is accompanied by the reduction of another ion or atom, usually a transition metal such as Fe or Co. The metal's ionization energy in the corresponding oxidation step correlates with the cell voltage, based on a decomposition of cohesive energy into electronic and ionic components. We relate the differences in cohesive energies to the chemical potential of lithium atoms, which is quantified, for instance for a two-phase electrode. The analysis is extended to a single-phase LixCoO2 cathode, whose average voltage can be calculated from the cohesive-energy difference between LiCoO2 and CoO2.

4.
Sensors (Basel) ; 24(16)2024 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-39204786

RESUMEN

SQM-ISS is a detector that will search from the International Space Station for massive particles possibly present among the cosmic rays. Among them, we mention strange quark matter, Q-Balls, lumps of fermionic exotic compact stars, Primordial Black Holes, mirror matter, Fermi balls, etc. These compact, dense objects would be much heavier than normal nuclei, have velocities of galaxy-bound systems, and would be deeply penetrating. The detector is based on a stack of scintillator and piezoelectric elements which can provide information on both the charge state and mass, with the additional timing information allowing to determine the speed of the particle, searching for particles with velocities of the order of galactic rotation speed (v ≲ 250 km/s). In this work, we describe the apparatus and its observational capabilities.

5.
Chemphyschem ; : e202400493, 2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39136933

RESUMEN

Aluminum (Al) is one of the most promising active materials for producing next-generation negative electrodes for lithium (Li)-ion batteries. It features low density, high specific capacity, and low working potential, making it ideal for producing energy-dense cells. However, this material loses its electrochemical activity within 100 cycles, making it practically unusable. Several claims in the literature support the idea that a dual degradation mechanism is at play. Firstly, the slow diffusion of Li in the Al matrix causes the electrochemical reactions to be partly irreversible, making the initial capacity of the cell drop. Second, the stresses caused by cycling make the active material pulverize and lose activity. Recent work shows that shortening the diffusion path of Li by 3D structuring is an effective way to mitigate the first capacity loss mechanism, while alloying Al with other elements effectively mitigates the second one. In this work, we demonstrate that the benefits of 3D structuring and alloying are cumulative and that a mesh made of an Al-magnesium alloy performs better than both a pure Al foil and a foil of an Al-Mg alloy.

6.
Sci Rep ; 14(1): 13413, 2024 06 11.
Artículo en Inglés | MEDLINE | ID: mdl-38862556

RESUMEN

In the food industry, the increasing use of automatic processes in the production line is contributing to the higher probability of finding contaminants inside food packages. Detecting these contaminants before sending the products to market has become a critical necessity. This paper presents a pioneering real-time system for detecting contaminants within food and beverage products by integrating microwave (MW) sensing technology with machine learning (ML) tools. Considering the prevalence of water and oil as primary components in many food and beverage items, the proposed technique is applied to both media. The approach involves a thorough examination of the MW sensing system, from selecting appropriate frequency bands to characterizing the antenna in its near-field region. The process culminates in the collection of scattering parameters to create the datasets, followed by classification using the Support Vector Machine (SVM) learning algorithm. Binary and multiclass classifications are performed on two types of datasets, including those with complex numbers and amplitude data only. High accuracy is achieved for both water-based and oil-based products.


Asunto(s)
Bebidas , Embalaje de Alimentos , Aprendizaje Automático , Microondas , Máquina de Vectores de Soporte , Bebidas/análisis , Contaminación de Alimentos/análisis , Algoritmos , Análisis de los Alimentos/métodos
7.
J Clin Med ; 13(10)2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38792300

RESUMEN

Background: Retrograde intrarenal surgery (RIRS) using flexible ureterorenoscopes is a cornerstone approach for renal stone removal, yet it carries a significant risk of postoperative urinary tract infection (UTI). With the emergence of single-use ureterorenoscopes, there is growing interest in their potential to mitigate this risk. This study aimed to compare the postoperative infection rates between single-use and multi-use ureterorenoscopes in RIRS procedures and to identify predictors of postoperative UTI. Methods: Data were collected from 112 consecutive patients who underwent RIRS for renal stones between March 2022 and September 2023. Peri-operative variables including age, gender, body mass index (BMI), stone size, stone location, type of ureterorenoscope, Hounsfield Units (HU), pre-operative hydronephrosis, laboratory analysis, and operative time were evaluated. Univariate and multivariate logistic regression analyses were performed to assess the predictors of postoperative UTI. Results: Of the cohort, 77 surgeries (68.7%) utilized multi-use ureterorenoscopes, while 35 (31.3%) utilized single-use devices. Stone diameter, number of stones, type of ureterorenoscope, and operative time were significant predictors of postoperative UTI in the univariate analysis. Multivariable logistic regression showed that operative time (OR, 1.3; 95% CI, 0.55-0.99; p = 0.03) and type of ureterorenoscope (multi-use vs. single-use) (OR, 1.14; 95% CI, 1.08-1.2; p < 0.001) were independent predictors of postoperative UTI. Conclusions: In conclusion, this study highlights that multi-use ureterorenoscopes and prolonged operative time are associated with an increased risk of postoperative UTI in RIRS procedures. Careful pre-operative evaluation and meticulous patient selection are essential to minimize the occurrence of postoperative UTIs and optimize patient outcomes in RIRS for renal stones.

8.
Chempluschem ; 89(8): e202400195, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38666666

RESUMEN

Silicon (Si) and silicon/graphite (Si/Gr) composite anodes are promising candidates due to their high theoretical capacity, low operating potential and natural abundance for high energy density Li-ion batteries. Green electrode production, eliminating organic volatile solvents require advancement of aqueous electrodes. Engineering the binder plays a critical role for improving waterborne electrodes. Lithium substituted polyacrylic acid LiPAA has been demonstrated as a promising binder for Si/Gr anodes and for Ni-rich cathodes in different cell configurations. LiPAA is utilized to minimize the volume expansion during cycling for Si/Gr anodes. LiPAA is formed in situ during cathode slurry preparation to regulate the pH and dimmish the Li loss. Using advanced characterization techniques, we investigated the slurries, electrodes, and active material reaction with LiPAA and its effect to the cycling performance. Our results indicate that the performance of high Si containing anode is limited by the amount of Si in the electrode. The failure mechanism with respect to high Si content was studied thoroughly. Aqueous processed cathodes with LiPAA binder in combination with Si anodes outperformed NMP based cathodes. Hence, LiPAA was successfully utilized as an active binder for both a high Si containing anode and for a Ni rich cathode.

9.
J Pers Med ; 13(8)2023 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-37623483

RESUMEN

Since its introduction in the early 2000s, robotic surgery has represented a significative innovation within a minimally invasive surgery approach. A variety of robotic platforms have been made available throughout the years, and the outcomes related to those platforms have been described in the literature for many types of surgeries. Medtronic's HugoTM RAS system is one of the newest robotic generations launched, but because of its recent placing on the field, comprehensive clinical data are still lacking. The aim of the present state of the art is to address the current literature concerning the use of the HugoTM RAS robot in order to report its feasibility, safety and clinical applications in different surgical branches. Two reviewers independently conducted a search on the "PubMed" electronic database, using the keywords "Hugo" and "Hugo RAS". After the initial screening of 35 results, a total of 15 articles concerning the Hugo RAS system were selected for the review, including both oncological and benign surgery. Patients' demographic and baseline data were compared including, when available, docking system times, complications and oncological outcomes in the fields of urologic, gynecologic and general surgery. With reference to urological procedures, a total of 156 robot-assisted radical prostatectomies, 10 robot-assisted partial nephrectomies, and 5 robot-assisted adrenalectomies were performed, involving a total of 171 patients. The surgical branch in which the Hugo system found its major application was urology, which was followed by gynecology and general surgery. The Hugo RAS system by Medtronic represents an innovative and safe surgical platform, with excellent perspective for the future and different clinical applications in many surgical branches. More studies are needed to validate the safety and results from this new robotic platform.

10.
Sci Rep ; 13(1): 9039, 2023 06 03.
Artículo en Inglés | MEDLINE | ID: mdl-37270634

RESUMEN

The presence in nature of species showing drastic differences in lifespan and cancer incidence has recently increased the interest of the scientific community. In particular, the adaptations and the genomic features underlying the evolution of cancer-resistant and long-lived organisms have recently focused on transposable elements (TEs). In this study, we compared the content and dynamics of TE activity in the genomes of four rodent and six bat species exhibiting different lifespans and cancer susceptibility. Mouse, rat, and guinea pig genomes (short-lived and cancer-prone organisms) were compared with that of naked mole rat (Heterocephalus glaber) which is a cancer-resistant organism and the rodent with the longest lifespan. The long-lived bats of the genera Myotis, Rhinolophus, Pteropus and Rousettus were instead compared with Molossus molossus, which is one of the organisms with the shortest lifespan among the order Chiroptera. Despite previous hypotheses stating a substantial tolerance of TEs in bats, we found that long-lived bats and the naked mole rat share a marked decrease of non-LTR retrotransposons (LINEs and SINEs) accumulation in recent evolutionary times.


Asunto(s)
Quirópteros , Neoplasias , Animales , Cobayas , Ratones , Quirópteros/genética , Retroelementos/genética , Incidencia , Envejecimiento , Ratas Topo/genética , Neoplasias/epidemiología , Neoplasias/genética , Neoplasias/veterinaria
11.
Small ; 19(42): e2302868, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37345577

RESUMEN

Here it is described nanogels (NG) based on a chitosan matrix, which are covalently stabilized by a bisamide derivative of Mn-t-CDTA (t-CDTA = trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid). the Mn(II) complex acts both as a contrast medium and as a cross-linking agent. These nanogels are proposed as an alternative to the less stable paramagnetic nanogels obtained by electrostatic interactions between the polymeric matrix and paramagnetic Gd(III) chelates. The present novel nanogels show: i) relaxivity values seven times higher than that of typical monohydrated Mn(II) chelates at the clinical fields, thanks to the combination of a restricted mobility of the complex with a fast exchange of the metal-bound water molecule; ii) high stability of the formulation over time at pH 5 and under physiological conditions, thus excluding metal leaking or particles aggregation; iii) good extravasation and accumulation, with a maximum contrast achieved at 24 h post-injection in mice bearing subcutaneous breast cancer tumor; iv) high T1 contrast (1 T) in the tumor 24 h post-injection. These improved properties pave the way for the use of these paramagnetic nanogels as promising magnetic resonance imaging (MRI) probes for in vitro and in vivo preclinical applications.


Asunto(s)
Imagen por Resonancia Magnética , Neoplasias , Ratones , Animales , Nanogeles , Imagen por Resonancia Magnética/métodos , Quelantes/química , Medios de Contraste/química
12.
World J Pediatr Congenit Heart Surg ; 14(2): 175-179, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36866595

RESUMEN

There has been a paradigm shift in the management of patients with congenital heart disease with a move away from conventional surgical treatment in favor of a percutaneous catheter-based approach across the spectrum of valvular heart diseases. The Sapien S3 valve implantation in the pulmonary position has been previously reported using a conventional transcatheter approach in patients with pulmonary insufficiency due to an enlarged right ventricular outflow tract. In this report, we present 2 unique cases of intraoperative hybrid implantation of Sapien S3 valves in patients with complex pulmonic and tricuspid valvular disease.


Asunto(s)
Enfermedades de las Válvulas Cardíacas , Implantación de Prótesis de Válvulas Cardíacas , Prótesis Valvulares Cardíacas , Insuficiencia de la Válvula Pulmonar , Válvula Pulmonar , Humanos , Cateterismo Cardíaco/métodos , Catéteres , Enfermedades de las Válvulas Cardíacas/diagnóstico por imagen , Enfermedades de las Válvulas Cardíacas/cirugía , Implantación de Prótesis de Válvulas Cardíacas/métodos , Diseño de Prótesis , Válvula Pulmonar/cirugía , Insuficiencia de la Válvula Pulmonar/cirugía , Resultado del Tratamiento , Masculino , Femenino , Adolescente , Adulto
13.
World J Pediatr Congenit Heart Surg ; 14(3): 384-386, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36972503

RESUMEN

The arterial switch operation with single coronary artery variance is an independent risk factor for increased operative mortality. There are reports of technical modifications, such as the double-barreled sinus pouch configuration, to improve geometric reimplantation of the single coronary into the neoaortic sinus. We describe the novel application of this technique for transferring a single coronary artery with a separate nodal artery emanating from the opposite sinus during an arterial switch operation.


Asunto(s)
Operación de Switch Arterial , Anomalías de los Vasos Coronarios , Transposición de los Grandes Vasos , Humanos , Operación de Switch Arterial/métodos , Vasos Coronarios/diagnóstico por imagen , Vasos Coronarios/cirugía , Transposición de los Grandes Vasos/diagnóstico por imagen , Transposición de los Grandes Vasos/cirugía , Corazón , Anomalías de los Vasos Coronarios/diagnóstico por imagen , Anomalías de los Vasos Coronarios/cirugía , Estudios Retrospectivos
14.
Sensors (Basel) ; 22(24)2022 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-36560066

RESUMEN

Frequency-modulated continuous wave (FMCW) radars are currently being investigated for remote vital signs monitoring (measure of respiration and heart rates) as an innovative wireless solution for healthcare and ambient assisted living. However, static reflectors (furniture, objects, stationary body parts, etc.) within the range or range angular bin where the subject is present contribute in the Doppler signal to a direct current (DC) offset. The latter is added to the person's information, containing also a useful DC component, causing signal distortion and hence reducing the accuracy in measuring the vital sign parameters. Removing the sole contribution of the unwanted DC offset is fundamental to perform proper phase demodulation, so that accurate vital signs monitoring can be achieved. In this work, we analyzed different DC offset calibration methods to determine which one achieves the highest accuracy in measuring the physiological parameters as the transmitting frequency varies. More precisely, by using two FMCW radars, operating below 10 GHz and at millimeter wave (mmWave), we applied four DC offset calibration methods to the baseband radar signals originated by the cardiopulmonary activities. We experimentally determined the accuracy of the methods by measuring the respiration and the heart rates of different subjects in an office setting. It was found that the linear demodulation outperforms the other methods if operating below 10 GHz while the geometric fitting provides the best results at mmWave.


Asunto(s)
Radar , Procesamiento de Señales Asistido por Computador , Humanos , Monitoreo Fisiológico/métodos , Signos Vitales , Respiración , Frecuencia Cardíaca/fisiología , Algoritmos
15.
Sensors (Basel) ; 22(24)2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36560268

RESUMEN

Unmanned ground vehicles (UGVs) find extensive use in various applications, including that within industrial environments. Efforts have been made to develop cheap, portable, and light-ranging/positioning systems to accurately locate their absolute/relative position and to automatically avoid potential obstacles and/or collisions with other drones. To this aim, a promising solution is the use of ultrasonic systems, which can be set up on UGVs and can potentially output a precise reconstruction of the drone's surroundings. In this framework, a so-called frequency-modulated continuous wave (FMCW) scheme is widely employed as a distance estimator. However, this technique suffers from low repeatability and accuracy at ranges of less than 50 mm when used in combination with low-resource hardware and commercial narrowband transducers, which is a distance range of the utmost importance to avoid potential collisions and/or imaging UGV surroundings. We hereby propose a modified FMCW-based scheme using an ad hoc time-shift of the reference signal. This was shown to improve performance at ranges below 50 mm while leaving the signal unaltered at greater distances. The capabilities of the modified FMCW were evaluated numerically and experimentally. A dramatic enhancement in performance was found for the proposed FMCW with respect to its standard counterpart, which is very close to that of the correlation approach. This work paves the way for the future use of FMCWs in applications requiring high precision.

16.
J Card Surg ; 37(12): 5649-5652, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36183397

RESUMEN

Systemic right ventricular failure after physiologic repair for dextro-transposition of the great arteries can be managed with durable mechanical circulatory support; however, the right ventricular morphology, such as intervening papillary muscles, presents challenges to inflow cannula positioning. Papillary muscle repositioning is an innovative technique to circumvent obstructive anatomy.


Asunto(s)
Insuficiencia Cardíaca , Transposición de los Grandes Vasos , Humanos , Transposición de los Grandes Vasos/cirugía , Músculos Papilares/cirugía , Planta de la Mostaza , Insuficiencia Cardíaca/cirugía , Arterias
17.
Inorg Chem ; 61(33): 13199-13209, 2022 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-35944034

RESUMEN

The GdAAZTA (AAZTA = 6-amino-6-methylperhydro-1,4-diazepinetetraacetic acid) complex represents a platform of great interest for the design of innovative MRI probes due to its remarkable magnetic properties, thermodynamic stability, kinetic inertness, and high chemical versatility. Here, we detail the synthesis and characterization of new derivatives functionalized with four amino acids with different molecular weights and charges: l-serine, l-cysteine, l-lysine, and l-glutamic acid. The main reason for conjugating these moieties to the ligand AAZTA is the in-depth study of the chemical properties in aqueous solution of model compounds that mimic complex structures based on polypeptide fragments used in molecular imaging applications. The analysis of the 1H NMR spectra of the corresponding Eu(III)-complexes indicates the presence of a single isomeric species in solution, and measurements of the luminescence lifetimes show that functionalization with amino acid residues maintains the hydration state of the parent complex unaltered (q = 2). The relaxometric properties of the Gd(III) chelates were analyzed by multinuclear and multifrequency NMR techniques to evaluate the molecular parameters that determine their performance as MRI probes. The relaxivity values of all of the novel chelates are higher than that of GdAAZTA over the entire range of applied magnetic fields because of the slower rotational dynamics. Data obtained in reconstituted human serum indicate the occurrence of weak interactions with the proteins, which result in larger relaxivity values at the typical imaging fields. Finally, all of the new complexes are characterized by excellent chemical stability in biological matrices over time, by the absence of transmetallation processes, or the formation of ternary complexes with oxyanions of biological relevance. In particular, the kinetic stability of the new complexes, measured by monitoring the release of Gd3+ in the presence of a large excess of Zn2+, is ca. two orders of magnitude higher than that of the clinical MRI contrast agent GdDTPA.


Asunto(s)
Aminoácidos , Gadolinio , Quelantes/química , Medios de Contraste/química , Gadolinio/química , Humanos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética
18.
Front Pediatr ; 10: 900142, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35874587

RESUMEN

Transposition of great arteries (d-TGA) is often associated with various coronary artery (CA) patterns. These anomalous patterns can cause variable clinical symptoms of coronary ischemia including sudden death. CA pattern is one of the major determinants of outcome in TGA postoperatively. An advanced cardiac imaging and a multidisciplinary care approach are essential for a favorable outcome. Here, we describe a novel CA origin pattern in a neonate with d-TGA, who developed myocardial ischemia and required a coronary unroofing procedure for a full recovery.

19.
J Am Heart Assoc ; 11(14): e026517, 2022 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-35861815

RESUMEN

Background Until recently, a large right ventricle outflow tract interfered with the feasibility of standard transcatheter pulmonary valve replacement (PVR). We are describing our experience using a hybrid approach for PVR using a left anterior thoracotomy approach to allow for plication of the main pulmonary artery followed by a transcatheter PVR using a Sapien S3 valve. Methods and Results This is a single-center, retrospective review of patients who were evaluated to be appropriate for a hybrid PVR approach. The patients' demographics, procedure details, and follow-up data were collected. Between May 2018 and April 2021, a total of 11 patients presented for hybrid transcatheter PVR. The median age and weight were 24 years (interquartile range, 19-43 years) and 81.8 kg (interquartile range, 69-91 kg), respectively. Nine out of 11 patients received a transcatheter PVR after main pulmonary artery plication. There were no procedurally related deaths. One major complication was encountered in which the valve was malpositioned requiring successful surgical PVR. Minor complications included acute kidney injury (n=1) and a broken rib (n=1). The median length of stay was 4 days (interquartile range, 2-4 days), with median follow-up of 7 months (interquartile range, 3-18 months). A well-functioning pulmonary valve was observed in all patients at the last follow-up. Conclusions A hybrid approach using left anterior thoracotomy with pulmonary artery plication followed by transcatheter Sapien S3 PVR provides a less-invasive option for patients with an enlarged right ventricular outflow tract. Preliminary results demonstrated this to be a safe option with good short-term outcomes.


Asunto(s)
Implantación de Prótesis de Válvulas Cardíacas , Prótesis Valvulares Cardíacas , Insuficiencia de la Válvula Pulmonar , Válvula Pulmonar , Tetralogía de Fallot , Cateterismo Cardíaco/efectos adversos , Prótesis Valvulares Cardíacas/efectos adversos , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Implantación de Prótesis de Válvulas Cardíacas/métodos , Ventrículos Cardíacos , Humanos , Arteria Pulmonar/diagnóstico por imagen , Arteria Pulmonar/cirugía , Válvula Pulmonar/diagnóstico por imagen , Válvula Pulmonar/cirugía , Estudios Retrospectivos , Tetralogía de Fallot/cirugía , Toracotomía/efectos adversos , Resultado del Tratamiento
20.
Ultrasonics ; 125: 106781, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35671568

RESUMEN

The concept of employing air volumes trapped inside polymer shells to make a lens for ultrasound focusing in water is investigated. The proposed lenses use evenly-spaced concentric rings, each having an air-filled polymer shell construction, defining concentric water-filled channels. Numerical simulations and experiments have shown that a plane wave can be focused, and that the amplification can be boosted by Fabry-Pérot resonances within the water channels with an appropriate choice of the lens thickness. The effect of the polymer shell thickness and the depth of the channels is discussed, as these factors can affect the geometry and hence the frequency of operation. The result was a lens with a Full Width at Half Maximum value of 0.65 of a wavelength at the focus. Results obtained on a metal-based counterpart are also shown for comparison. An advantage of this polymeric design is that it is easily constructed via additive manufacturing. This study shows that trapped-air lenses made of polymer are suitable for ultrasound focusing in water near 500 kHz.

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