Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.938
Filtrar
1.
Biomaterials ; 312: 122709, 2025 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-39094521

RESUMO

Sonodynamic therapy (SDT) relies heavily on the presence of oxygen to induce cell death. Its effectiveness is thus diminished in the hypoxic regions of tumor tissue. To address this issue, the exploration of ultrasound-based synergistic treatment modalities has become a significant research focus. Here, we report an ultrasonic cavitation effect enhanced sonodynamic and 1208 nm photo-induced cancer treatment strategy based on thermoelectric/piezoelectric oxygen-defect bismuth oxychloride nanosheets (BNs) to realize the high-performance eradication of tumors. Upon ultrasonic irradiation, the local high temperature and high pressure generated by the ultrasonic cavitation effect combined with the thermoelectric and piezoelectric effects of BNs create a built-in electric field. This facilitates the separation of carriers, increasing their mobility and extending their lifetimes, thereby greatly improving the effectiveness of SDT and NIR-Ⅱ phototherapy on hypoxia. The Tween-20 modified BNs (TBNs) demonstrate ∼88.6 % elimination rate against deep-seated tumor cells under hypoxic conditions. In vivo experiments confirm the excellent antitumor efficacy of TBNs, achieving complete tumor elimination within 10 days with no recurrences. Furthermore, due to the high X-ray attenuation of Bi and excellent NIR-Ⅱ absorption, TBNs enable precise cancer diagnosis through photoacoustic (PA) imaging and computed tomography (CT).


Assuntos
Bismuto , Neoplasias da Mama , Oxigênio , Terapia por Ultrassom , Bismuto/química , Feminino , Animais , Neoplasias da Mama/terapia , Terapia por Ultrassom/métodos , Oxigênio/química , Camundongos , Camundongos Endogâmicos BALB C , Humanos , Linhagem Celular Tumoral , Raios Infravermelhos , Nanoestruturas/química , Fototerapia/métodos
2.
ACS Sens ; 2024 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-39356837

RESUMO

Advanced technologies employed in modern respiratory airflow transducers have exhibited powerful capabilities in accurately measuring respiratory flow under controlled and sedentary conditions, particularly in clinical settings. However, the wearable applicability of these transducers as face-mounted electronics for use in occupational and sporting activities remains unexplored. The present review addresses the critical wearability issue associated with current respiratory airflow transducers, including pneumotachographs, orifice flowmeters, turbine flowmeters, hot wire anemometers, ultrasound flowmeters, and piezoelectric airflow transducers. Furthermore, a comprehensive analysis and comparison of all factors that impact the wearable applicability of respiratory airflow transducers are conducted, considering dynamic accuracy, long-term usability, power consumption, calibration frequency, and cleaning requirements. The findings indicate that the piezoelectric airflow transducer stands out as a more viable option for wearables compared to other devices. We expect that this review will serve as a valuable engineering reference, guiding future research efforts in designing and developing wearable respiratory airflow transducers for ambulatory respiratory flow monitoring.

3.
Artigo em Inglês | MEDLINE | ID: mdl-39360618

RESUMO

The application of traditional isocyanate-based polyimide (PI) foams is highly hindered due to limited flame retardancy, poor mechanical properties, and relatively single functionality. Herein, we propose an effective method to fabricate dual cross-linked polyimide/bismaleimide (PI-BMI) foams with outstanding heat resistance and enhanced mechanical properties by incorporating bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (ME-BMI) as the interpenetrating network. The results show that the prepared PI-BMI composite foams exhibit enhanced mechanical properties with lightweight characteristics (23-80 kg·m-3). When the ME-BMI loading reached 120 wt %, the tensile and compressive strength of PI-BMI composite foam can reach 1.9 and 7.8 MPa, which are 9.6 and 63.3 times higher than that of pure PI foam, respectively. In comparison with PIF-0, the 10% heat loss temperature (Td,10%) of PIF-90 improved by 156 °C. Moreover, the PI-BMI foam piezoelectric sensor containing fluorine groups presents a short response time (14.22 ms), high sensitivity (0.266 V/N), and outstanding stability (10 000 cycles). Besides, the sensor can accurately monitor human activity in different states. This work provides a promising strategy for designing multifunctional PI foams, making them suitable for applications in aerospace and microelectronics.

4.
Front Bioeng Biotechnol ; 12: 1473126, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39359264

RESUMO

Piezoelectric materials, as a class of materials capable of generating electrical charges under mechanical vibration, have special piezoelectric effects and have been widely applied in various disease treatment fields. People generate vibrations in the oral cavity during daily activities such as brushing teeth, using electric toothbrushes, chewing, and speaking. These natural vibrations (or external ultrasound) provide ideal conditions for activating piezoelectric materials, leading to their high potential applications in protecting oral health and treating oral diseases. Based on this, this review reports on the research progress and trends of piezoelectric materials in the protection of oral health and the treatment of oral diseases in the past 5 years, and discusses its treatment mechanism, challenges and shortcomings, aiming to provide theoretical basis and new ideas for the future application of piezoelectric materials in the field of oral cavity. Finally, a brief outlook is provided, suggesting that the potential of piezoelectric materials may enable them to quickly move towards real clinical applications.

5.
3D Print Addit Manuf ; 11(3): e1073-e1086, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39359608

RESUMO

This study describes an intelligent method for modeling and optimization of piezoelectric ejection system design for additive manufacturing. It is a combination of neural network (NN) techniques and finite element simulation (FES) that allows designing each parameter of a piezoelectric ejection system faster and more reliably than conventional methods. Using experimental and literature data, a FE model of the droplet ejection process was developed and validated to predict two indexes of droplet ejection behavior (DEB): jetting velocity and droplet diameter. Two artificial neural network (ANN) models based on feed-forward back propagation were developed and optimized by genetic algorithm (GA). A database was established by FE calculations, and the models were trained to establish the relationship between the piezoelectric ejection system design input parameters and each DEB indicator. The results show that both NN models can independently predict the droplet jetting velocity and droplet diameter values from the training and testing data with high accuracy to determine the optimal piezoelectric ejection system design. Finally, the accuracy of the prediction results of the FES and ANN-GA models was verified experimentally. It was found that the errors between the predicted and experimental results were 4.48% and 3.18% for the jetting velocity and droplet diameter, respectively, verifying that the optimization method is reliable and robust for piezoelectric ejection system design optimization.

6.
Artigo em Inglês | MEDLINE | ID: mdl-39375944

RESUMO

Barium titanate (BaTiO3) is renowned for its high dielectric constant and remarkable piezoelectric attributes, positioning it as a key element in the advancement of environmentally sustainable devices. Nevertheless, the effectiveness of piezoelectric nanogenerators (PENGs) that integrate BaTiO3 nanoparticles (NPs) and poly(dimethylsiloxane) (PDMS) poses a challenge, thereby restricting their utility in energy harvesting applications. This study presents a direct approach involving the cyclic manipulation of direct current (DC) power supply terminals to achieve unidirectional alignment of BaTiO3 NPs within a PDMS matrix, aiming to enhance the performance of the PENGs. Examination of the morphology and evaluation of diffraction planes, notably (111) and (200), in the aligned BaTiO3 PENGs exhibited well-oriented structures resulting from the repetitive switching between two electrodes, leading to improved piezoelectric properties. The BaTiO3 PENGs manifested notably higher output power (∼15 V and 1.91 µA) in contrast to devices containing randomly distributed polarized BaTiO3-PDMS composite films. The generated power was sufficient to directly operate six light-emitting diodes (LEDs) connected in series, with a collective nominal voltage of around 14 V, encompassing red, green, and blue LEDs. Nanoindentation verified the enhanced piezoelectric characteristics attributed to the alignment, sensitivity to bending, and energy-cohesive effects of clustered BaTiO3 one-dimensional (1D) pillars. These findings suggest a widely applicable technique for aligning and situating nanoparticles vertically within a polymer matrix, exploiting the intrinsic dielectric properties of the nanoparticles through a straightforward electric field switching mechanism.

7.
J Colloid Interface Sci ; 679(Pt A): 324-334, 2024 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-39366262

RESUMO

Wearable piezoelectric nanogenerators (PENGs) are increasingly significant in healthcare and energy harvesting applications due to their ability to convert mechanical energy into electrical signals. In this study, we developed PENGs by incorporating crab shell powder (CS-NFs) into electrospun polyvinylidene fluoride (PVDF) nanofibers to enhance their piezoelectric properties. The PVDF-CS-NFs (PC-NFs) composites were evaluated for structural, thermal, and piezoelectric performance. The 1.5 wt% CS-NFs composite exhibited a notable improvement, with a maximum output voltage of 19 V under mechanical deformation, significantly higher than pristine PVDF NFs. Furthermore, the device demonstrated excellent sensitivity in real-time respiratory monitoring when applied to various body locations, including the chest, throat, and mask. Additionally, the PC-NFs-based PENGs were capable of charging a 2.2 µF capacitor to 2 V within 180 s and powering 56 LEDs. These results underscore the potential of using sustainable crab shell waste in biocompatible, eco-friendly piezoelectric devices for wearable sensors and energy harvesting applications.

8.
Heliyon ; 10(19): e37195, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39386785

RESUMO

In inertia impact piezoelectric actuators, the phenomenon of high-frequency drive-induced back-stepping poses a significant limitation to their overall performance. The ultra-fast response time of the piezoelectric stack enables the resolution of this issue. This paper introduces an inertia impact piezoelectric actuator operating under a novel Dual-Stack Motion Mode (DCMM), diverging from the traditional operation in the Single-Stack Motion Mode (STMM) that involves a solitary piezoelectric stack (PES) for active friction control. A comprehensive description of the actuator's structure and its operational principles under DCMM is provided. By constructing and experimentally evaluating the actuator using a controlled variable approach, a comparative analysis of performance between DCMM and STMM across various scenarios including different inertial mass blocks, driving voltages, frequencies, and load conditions was conducted. The experimental results indicate that DCMM significantly enhances the actuator's output performance, achieving a maximum speed of 1142.79 µm/s and a stable single-step displacement of 0.5 µm. The actuator features a simple yet effective structure and driving mechanism, allowing for multiple driving modes through the assembly of different inertial masses, thereby providing a substantial competitive advantage in output performance. The feasibility of using DCMM to improve actuator performance is corroborated by both theoretical and experimental studies. The ultra-fast response of the piezoelectric stacks expands the operational bandwidth of the actuator, achieving a seamless integration of speed and precision.

9.
Artigo em Inglês | MEDLINE | ID: mdl-39392297

RESUMO

Emerging portable energy systems with integrated sustainability and improved safety have garnered growing interest in wearable electronics. Herein, a self-charging zinc-ion battery is successfully developed by integrating a PVDF-ZnO piezoelectric separator immersed in a quasi-solid-state hydrogel electrolyte (prepared using a 3 m Zn(CF3SO3)2) solution that is sandwiched between a FeVO4 cathode and a zinc anode. This battery effectively captures energy through controlled tapping, eliminating the need for external charging and enabling sustainable energy storage. This self-charging battery can be charged up to 181.23 mV under continuous tapping for 300 s. Upon the cease of tapping, there is a slight decline in the induced potential, which then stabilizes and maintains a consistent potential. Five self-charging batteries connected in series and tapped simultaneously for 300 s generate a potential of 290 mV, whereas five batteries connected in series and tapped one by one induce a potential of 345 mV. This is the first time that a piezoelectric self-charging zinc-ion battery is reported. This study unveils a transformative strategy for realizing next-generation wearable electronics with a self-charging zinc-ion battery design that prioritizes both sustainability and safety.

10.
Ultrasonics ; 145: 107483, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39383711

RESUMO

Applications of guided waves in various fields of engineering and science rely on elastic wave emitters for wave generation. Accurate prediction and understanding of the far-field responses of these wave emitters are crucial for the reliable and efficient application of guided waves-based technologies. In this paper, we propose a novel semi-analytical framework capable of predicting the far-field response of complex wave emitters of arbitrary shape and internal structure in any type of substrate. This framework is general, and is not confined to specific methods, enhancing its versatility. We applied the proposed semi-analytical framework to predict the directivity patterns of two different macro-fiber composite transducers, accurately modeled using their exact topologies. The framework's validity was experimentally confirmed by comparing the predicted directivity patterns with the results obtained from experimental measurements.

11.
Water Res ; 268(Pt A): 122554, 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-39383804

RESUMO

Organic fouling and biofouling represents a critical challenge encountered by the membrane-based water treatment process. Herein, a piezoelectric PVDF membrane (PEM), capable of generating electrical responses to hydraulic pressure stimuli, was synthesized and employed for mitigating the fouling in surface water treatment. The surface-hydrophobilized PEM demonstrated sensitive and enhanced underwater output performance in response to increasing transmembrane pressure (TMP) during constant-flux filtration, with signals reaching up to ∼800 mV at a TMP of ∼80 kPa. This in-situ piezoelectric response significantly reduced TMP growth in both short-term (1 h) and long-term (15 days) filtration trials, demonstrating a strong capability to mitigate membrane fouling. Moreover, continuous piezoelectric stimulation effectively inhibited microbial activity and the accumulation of extracellular polymeric substances (EPS) on PEM surface, surpassing the dominant electrokinetic repulsion mechanisms observed in short-term trials. Microbial community analysis suggests that this evolution is primarily due to the targeted impact of piezoelectric stimulation on microbial metabolic behavior. The piezoelectric-induced electrical microenvironment inhibited the growth of microbes associated with high EPS production while promoting the proliferation of electrically active microbes involved in biopolymer digestion. In addition, the PEM demonstrated enhanced permeate quality throughout the filtration process, with DOC and UV254 removal rates increasing from 11.7 % and 15.6 % initially to 28.6 % and 19.5 % by the 15th day, respectively. Given the performance and self-powered capability of PEM compared to current electrified antifouling methods that require an external power supply, these attributes are anticipated to hold practical significance in developing innovative and energy-efficient strategies for mitigating both organic fouling and biofouling.

12.
ACS Biomater Sci Eng ; 10(10): 6061-6077, 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39353103

RESUMO

Because of their unique electromechanical coupling response, piezoelectric smart biomaterials demonstrated distinctive capability toward effective, efficient, and quick diagnosis and treatment of a wide range of diseases. Such materials have potentiality to be utilized as wireless therapeutic methods with ultrasonic stimulation, which can be used as self-powered biomedical devices. An emerging advancement in the realm of personalized healthcare involves the utilization of piezoelectric biosensors for a range of therapeutic diagnosis such as diverse physiological signals in the human body, viruses, pathogens, and diseases like neurodegenerative ones, cancer, etc. The combination of piezoelectric nanoparticles with ultrasound has been established as a promising approach in sonodynamic therapy and piezocatalytic therapeutics and provides appealing alternatives for noninvasive treatments for cancer, chronic wounds, neurological diseases, etc. Innovations in implantable medical devices (IMDs), such as implantable piezoelectric energy generator (iPEG), offer significant advantages in improving physiological functioning and ability to power a cardiac pacemaker and restore the heart function. This comprehensive review critically evaluates the role of piezoelectricity in disease diagnosis and treatment, highlighting the implication of piezoelectric smart biomaterials for biomedical devices. It also discusses the potential of piezoelectric materials in healthcare monitoring, tissue engineering, and other medical applications while emphasizing future trends and challenges in the field.


Assuntos
Materiais Biocompatíveis , Humanos , Materiais Biocompatíveis/uso terapêutico , Materiais Biocompatíveis/química , Técnicas Biossensoriais/métodos , Nanopartículas/uso terapêutico , Nanopartículas/química , Animais , Terapia por Ultrassom/métodos , Neoplasias/terapia , Neoplasias/diagnóstico , Engenharia Tecidual/métodos
13.
Nanomaterials (Basel) ; 14(19)2024 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-39404305

RESUMO

This study presents the development of flexible piezoelectric nanogenerators (PENGs) utilizing graphitic carbon nitride (g-C3N4) nanoflakes (CNNFs) and polyvinylidene fluoride (PVDF) composites fabricated via the direct ink writing (DIW) 3D printing method. A novel approach of synthesizing CNNFs using the ethanol exfoliation method was demonstrated, which significantly reduces preparation time and cost compared to traditional acid exfoliation. The CNNFs are incorporated into PVDFs at varying weight percentages (5, 7.5, 10, and 15 wt.%) to optimize the ß-phase content and piezoelectric properties. Characterization techniques including XRD, FTIR, and FESEM confirm the successful synthesis and alignment of nanoflakes inside the PVDF matrix. The film with 7.5% CNNF achieves the highest performance, exhibiting a peak output voltage of approximately 6.5 V under a 45 N force. This study also explores the effects of UV light exposure. Under a UV light, the film exhibits an output voltage of 8 V, indicating the device's durability and potential for practical applications. The fabricated device showed significant voltage outputs during various human motions, confirming its suitability for wearable self-powered IoT applications. This work highlights the efficacy of the ethanol exfoliation method and the DIW printing technique in enhancing the performance of flexible PENGs.

14.
ACS Appl Mater Interfaces ; 16(39): 53106-53115, 2024 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-39312748

RESUMO

The presence of abnormally oriented grains (AOGs) in sputter-deposited aluminum scandium nitride (AlScN) films significantly degrades their physical properties, compromising the performance of bulk acoustic wave (BAW) devices. This study utilizes first-principles calculations to reveal that in tetrahedral wurtzite AlScN film-doped Sc atoms tend to aggregate at the second nearest-neighbor positions, forming dense ScN octahedral structures. The rock-salt (RS) ScN continued to grow due to further Sc aggregation. However, due to inadequate scandium flux, embryonic RS structures cannot be sustained, resulting in the nucleation of AOGs at the (111) faces of the octahedral ScN structure. Electron microscopy studies indicated that AOGs possess wurtzite structures and originate at tilted grain boundaries. These boundaries were characterized as RS ScN with more Sc atoms. This corroborated the theoretical predictions. BAW resonators and filters fabricated from sputter-deposited AlScN films demonstrate that AOGs degraded the piezoelectricity of AlScN, reducing the resonator's electromechanical coupling coefficient (Keff2). Measurements showed that AOG density increased from edge to center of the 8 in. wafer, resulting in a 3% decrease in average Keff2 in the resonators and a 137 MHz decrease in the filter bandwidth at 5 dB.

15.
Biomater Adv ; 166: 214053, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39342781

RESUMO

Near-field electrospinning (NFES) has recently gained considerable interest in fabricating tissue engineering scaffolds. This technique combines the advantages of both 3D printing and electrospinning. It allows for the production of fibers with smaller resolution and the ability to make regular structures with suitable pores. In this study, a microfibrous composite scaffold of polycaprolactone (PCL)/hydroxyapatite (HA) was prepared by NFES in the first step. The microfibrous scaffold had a fiber spacing of 414.674 ± 24.9 µm with an average fiber diameter of 94.695 ± 16.149 µm. However, due to the large fiber spacing, the surface area was insufficient for cell adhesion. Therefore, the hybrid scaffold was prepared by adding aligned and random electrospun poly (L-lactic acid) (PLLA) nanofibers to the microfibrous scaffold. Cellular studies showed that cell adhesion to the hybrid scaffold increased by 334 % compared to the microfibrous scaffold. These nanofibers also exhibited piezoelectric properties, which helped stimulate bone regeneration. Aligned nanofibers in the hybrid scaffold enhanced alkaline phosphatase activity and the intensity of alizarin red staining 1.5 and 1.6 times, respectively, compared to the microfibrous scaffold. Furthermore, the elastic modulus and ultimate tensile strength increased by 268 % and 130 %, respectively, by adding aligned nanofibers to the microfibrous scaffold. Therefore, the hybrid microfibrous composite scaffold of PCL/HA containing aligned electrospun PLLA nanofibers with improved properties showed the potential for bone regeneration.

16.
Asian J Surg ; 2024 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-39343680

RESUMO

OBJECTIVE: Current study evaluated whether use of the platelet-rich powder (PRPP), piezosurgery device and diode laser after removal of jawbones cysts and benign bone formations and extraction of impacted tooth could enhance bone regeneration before dental implantation. METHODS: A study was conducted among 200 patients with post-surgical cavities (not exceeding 1.5 cm upon cystectomy, benign bone tumor removal and impacted tooth extraction) who underwent plasma powder, autograft, allograft, xenograft or beta-tricalcium phosphate augmentation procedures. RESULTS: PRPP implantation in combination with irradiation of bone cavity by diode laser led to the formation of 15.40 % ± 2.1 of new bone. The activity of reparative osteogenesis on the bone surface was BB = 6.71 ± 1.3, which is 3 and 3.5 times higher than the mean value in comparison group after augmentation of xenograft and beta-tricalcium phosphate. The value of bone tissue resorption for main group patients was less pronounced (Ra.Oc = 25.20 % ± 2.1). The ratio between pro- and anti-inflammatory cytokines in the main group after 1, 7 and 30 days since surgical procedure was lower than the ratio of the corresponding cytokines in the comparison groups. CONCLUSION: The examination of computed tomograms, histological and morphometric analysis of bone tissue after trepanobiopsy, cytological analysis of swabs and enzyme immunoassay to determine local immunity indicated that the proposed method of treatment with the use of PRPP, the piezosurgery device and the diode laser has a positive effect: it helped to optimize reparative osteogenesis after filling post-surgical cavities and restore bone volume.

17.
Nano Lett ; 24(39): 12148-12155, 2024 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-39311691

RESUMO

Defect dipoles are crucial for regulating electromechanical properties in piezoelectric ceramics, but their effects on polarization and electrostrain behaviors are still unclear. Here, a reasonable theoretical model is proposed and evidenced by experiments to address a long-standing puzzle of the relationship between the internal bias field and defect dipoles. By incorporating the additional polarization induced by defect dipoles, we refine the classical theory to account for the recently reported asymmetric giant-strain behaviors. Phase-field simulation reveals the electrostrain evolution in response to defect dipole elastic distortion and additional polarization. This work not only elucidates the effect of defect dipoles on polarization and electrostrain but also advances the theoretical understanding of defects in piezoelectrics.

18.
ACS Appl Mater Interfaces ; 16(40): 54359-54366, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39324784

RESUMO

Antiferroelectrics are fundamental mother compounds critical in developing innovative lead-free piezoelectrics and ferroelectrics and hold great promise for wide-ranging applications in energy conversion and electronic devices. However, harnessing their superior properties presents a significant challenge due to the delicate balance required between their various states. In this study, through the unique design of nanopillar structures to alleviate the local polar heterogeneity, we have achieved significantly improved piezo-/ferro-electricity in classic lead-free antiferroelectric AgxNbO3-δ (x = 1, 0.9, and 0.8) epitaxial thin films. The effective piezoelectric coefficient reaches 440 pm V-1, 1 order of magnitude larger than the stoichiometric AgNbO3, rivaling classic lead zirconate titanate piezoelectrics. Atomic-scale electron microscopy investigations unravel the underlying mechanisms. The nanopillars, characterized by antisite occupancy of both Ag and Nb atoms and forming out-of-phase boundaries with the matrix, reduce the local crystal symmetry via interphase strain. This leads to the creation of flexible multinanodomain structures that significantly facilitate polarization rotation, thus substantially enhancing the piezoelectric performance. This study demonstrates the feasibility of engineering local heterogeneity through nanopillar design, offering a generally applicable method for property improvement of a wide range of antiferroelectrics.

19.
ACS Appl Mater Interfaces ; 16(40): 54566-54573, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39344529

RESUMO

Serious haze pollution, mainly caused by fine and ultrafine particulate matters (PMs) and aerosols, poses a significant threat to the public health, especially when the aerodynamic diameter is less than 2.5 µm. Electrostatic capture techniques, such as polymer electret filters and kinetic plasma processes, are widely used instead of mechanical filtration with high removal efficiency and low wind resistance (pressure drop). However, the inability to recharge, coupled with the generation of ozone byproducts, makes it challenging to meet the requirements for both recoverability and highly efficient filtration. Here, we propose an electrostatic filter as an alternative to conventional polymer electrets, aiming to achieve an ultrahigh removal efficiency, long-term performance stability, and reusability. Piezoelectric LiNbO3 (LN) particles are integrated into the polypropylene (PP) matrix through the melt-blown strategy to fabricate the LN/PP nonwoven fabric. Benefiting from the employment of piezoelectric LN particles, the LN/PP nonwovens exhibit an ultrahigh removal efficiency of 99.9% for PM0.3 to PM10. The airflow facilitates the sustained regeneration of piezoelectric charges on the surface of LN/PP nonwovens, thereby maintaining a removal efficiency of approximately 95% for continuous filtration over 11 days. Even after eight cycles of washing, the removal efficiency of the LN/PP nonwovens remains at nearly 90%, demonstrating the excellent reusability. Our proposed strategy offers an ingenious combination of high-efficiency and recoverability for filters, holding great promise for reducing plastic pollution.

20.
World Neurosurg ; 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-39303974

RESUMO

OBJECTIVE: To verify the feasibility and discuss advantages and disadvantages of a piezoelectric orbitotomy during superior eyelid endoscopic transorbital approach (SETOA). An illustrative case demonstrating the application of this novel technique is also presented. METHODS: Exoscopic/endoscopic SETOA to middle cranial fossa was performed on 5 adult specimens. The surgical corridor was created via piezoelectric orbitotomy by performing 3 selective and safe micrometric bone cuts providing a 1-piece trapezoid bone flap, which was repositioned and secured at the end of the procedure. A three-dimensional scan of the bone flap allowed us to reconstruct a three-dimensional model and calculate its volume. RESULTS: Anatomical-morphometric quantitative analysis showed a mean bone volume gain of 1574.26 mm3 by using piezoelectric orbitotomy. Piezoelectric orbitotomy also yielded concrete surgical advantages and theoretical benefits in terms of functional and esthetic outcomes. All osteotomies were micrometric clear-cut and precise, resulting in a very thin bone gap; complete sparing of soft tissues and neurovascular structures in and around the orbit was observed. Lateral orbital wall reconstruction by replacing the bone flap was performed to mitigate the risk of enophthalmos, proptosis, cerebrospinal leakage, pseudomeningocele, and pulsatile headache, which represent significant challenges. CONCLUSIONS: Piezoelectric orbitotomy may offer a viable, selective, effective, safe alternative to high-speed drilling during SETOA, especially for patients with intra-axial pathologies, in which a watertight closure is mandatory. This procedure could prevent or decrease the risk of some of the main postoperative complications associated with standard SETOA, potentially resulting in better functional and esthetic outcomes.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...