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1.
PLoS One ; 19(5): e0302729, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38743667

RESUMO

The constitutive model and modulus parameter equivalence of shape memory alloy composites (SMAC) serve as the foundation for the structural dynamic modeling of composite materials, which has a direct impact on the dynamic characteristics and modeling accuracy of SMAC. This article proposes a homogenization method for SMA composites considering interfacial phases, models the interface stress transfer of three-phase cylinders physically, and derives the axial and shear stresses of SMA fiber phase, interfacial phase, and matrix phase mathematically. The homogenization method and stress expression were then used to determine the macroscopic effective modulus of SMAC as well as the stress characteristics of the fiber phase and interface phase of SMA. The findings demonstrate the significance of volume fraction and tensile pre-strain in stress transfer between the fiber phase and interface phase at high temperatures. The maximum axial stress in the fiber phase is 705.05 MPa when the SMA is fully austenitic and the pre-strain increases to 5%. At 10% volume fraction of SMA, the fiber phase's maximum axial stress can reach 1000 MPa. Ultimately, an experimental verification of the theoretical calculation method's accuracy for the effective modulus of SMAC lays the groundwork for the dynamic modeling of SMAC structures.


Assuntos
Ligas , Estresse Mecânico , Resistência à Tração , Ligas/química , Teste de Materiais/métodos , Módulo de Elasticidade , Materiais Inteligentes/química , Modelos Teóricos
2.
Mikrochim Acta ; 191(6): 330, 2024 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-38744738

RESUMO

In view of a large number of people infected with Helicobacter pylori (H. pylori) with great harm followed, there is an urgent need to develop a non-invasive, easy-to-operate, and rapid detection method, and to identify effective sterilization strategies. In this study, highly specific nanoprobes with nanozyme activity, Ag@Pt nanoparticles (NPs) with the antibody, were utilized as a novel lateral flow immunoassay (LFIA). The optical label (Ag@Pt NPs) was enhanced by the introduction of the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) and compared with a gold nanoparticles (Au NPs) optical label. Under the optimal condition, Ag@Pt-LFIA and TMB-enhanced Ag@Pt-LFIA for H. pylori were successfully established, two of which were over twofold and 100-fold more sensitive than conventional visual Au NP-based LFIA, respectively. Furthermore, Ag@Pt NPs with the antibody irradiated with NIR laser (808 nm) at a power intensity of 550 mW/cm2 for 5 min exhibited a remarkable antibacterial effect. The nanoprobes could close to bacteria through effective interactions between antibodies and bacteria, thereby benefiting photothermal sterilization. Overall, Ag@Pt NPs provide promising applications in pathogen detection and therapeutic applications.


Assuntos
Ligas , Helicobacter pylori , Nanopartículas Metálicas , Platina , Prata , Helicobacter pylori/efeitos da radiação , Helicobacter pylori/efeitos dos fármacos , Prata/química , Nanopartículas Metálicas/química , Platina/química , Ligas/química , Antibacterianos/farmacologia , Antibacterianos/química , Imunoensaio/métodos , Benzidinas/química , Ouro/química , Humanos , Esterilização/métodos , Limite de Detecção
3.
BMC Oral Health ; 24(1): 564, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38745154

RESUMO

BACKGROUND: Alterations in the mechanical properties of the materials utilized in orthodontic appliances could affect the working properties of the appliances, thereby affecting clinical progress and outcome. Numerous studies have confirmed the correlation between alloy corrosion and raised surface roughness, which has a direct impact on the working characteristics of orthodontic archwires. METHODS: Thirty nickel-titanium (NiTi) orthodontic archwires were utilized in this study. Patients were randomly selected and allocated into three groups according to the randomization plan; (The control group): subjects practiced regular oral hygiene; (The fluoride group): subjects used fluoride for intensive prophylaxis; (The chlorhexidine group): subjects used chlorhexidine. Representative samples were evaluated by SEM, and then SEM images with high resolution were examined using Image J software to determine the surface roughness and obtain the results for further statistical analysis. RESULTS: Our findings indicated a significant difference was found between the three groups regarding the anterior and posterior parts between the control and the two other groups and a non-significant difference between NaF and CHX groups. Overall, the p-value for group comparisons was 0.000 for both parts, indicating a highly significant difference especially between the control and NaF groups. CONCLUSION: Mouthwashes containing sodium fluoride demonstrated more significant surface alterations than the control and CHX groups and should be prescribed in accordance with orthodontic materials to reduce side effects.


Assuntos
Ligas , Clorexidina , Ligas Dentárias , Microscopia Eletrônica de Varredura , Níquel , Fios Ortodônticos , Fluoreto de Sódio , Propriedades de Superfície , Humanos , Fluoreto de Sódio/uso terapêutico , Clorexidina/uso terapêutico , Corrosão , Ligas Dentárias/química , Níquel/química , Titânio/química , Cariostáticos/uso terapêutico , Cariostáticos/química , Masculino , Feminino , Adulto Jovem , Antissépticos Bucais/uso terapêutico , Antissépticos Bucais/química , Processamento de Imagem Assistida por Computador/métodos , Adolescente , Adulto , Higiene Bucal
4.
J Appl Biomater Funct Mater ; 22: 22808000231214359, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38702952

RESUMO

Exploring high strength materials with a higher concentration of reinforcements in the alloy proves to be a challenging task. This research has explored magnesium-based composites (AZ31B alloy) with tungsten carbide reinforcements, enhancing strength for medical joint replacements via league championship optimisation. The primary objective is to enhance medical joint replacement biomaterials employing magnesium-based composites, emphasising the AZ31B alloy with tungsten carbide reinforcements. The stir casting method is utilised in the manufacture of magnesium matrix composites (MMCs), including varied percentages of tungsten carbide (WC). The mechanical characteristics, such as micro-hardness, tensile strength, and yield strength, have been assessed and compared with computational simulations. The wear studies have been carried out to analyse the tribological behaviour of the composites. Additionally, this study investigates the prediction of stress and the distribution of forces inside bone and joint structures, therefore offering significant contributions to the field of biomedical research. This research contemplates the use of magnesium-based MMCs for the discovery of biomaterials suitable for medical joint replacement. The study focuses on the magnesium alloy AZ31B, with particles ranging in size from 40 to 60 microns used as the matrix material. Moreover, the outcomes have revealed that when combined with MMCs based on AZ31B-magnesium matrix, the WC particle emerges as highly effective reinforcements for the fabrication of lightweight, high-strength biomedical composites. This study uses the league championship optimisation (LCO) approach to identify critical variables impacting the synthesis of Mg MMCs from an AZ31B-based magnesium alloy. The scanning electron microscopy (SEM) images are meticulously analysed to depict the dispersion of WC particulates and the interface among the magnesium (Mg) matrix and WC reinforcement. The SEM analysis has explored the mechanisms underlying particle pull-out, the characteristics of inter-particle zones, and the influence of the AZ31B matrix on the enhancement of the mechanical characteristics of the composites. The application of finite element analysis (FEA) is being used in order to make predictions regarding the distribution of stress and the interactions of forces within the model of the hip joint. This study has compared the physico-mechanical and tribological characteristics of WC to distinct combinations of 0%, 5%, 10% and 15%, and its impact on the performance improvements. SEM analysis has confirmed the findings' improved strength and hardness, particularly when 10%-15% of WC was incorporated. Following the incorporation of 10% of WC particles within Mg-alloy matrix, the outcomes of the study has exhibited enhanced strength and hardness, which furthermore has been evident by utilising SEM analysis. Using ANSYS, structural deformation and stress levels are predicted, along with strength characteristics such as additional hardness of 71 HRC, tensile strength of 140-150 MPa, and yield strength closer to 100-110 MPa. The simulations yield significant insights into the behaviour of the joint under various loading conditions, thus enhancing the study's significance in biomedical environments.


Assuntos
Ligas , Magnésio , Teste de Materiais , Ligas/química , Magnésio/química , Compostos de Tungstênio/química , Materiais Biocompatíveis/química , Humanos , Resistência à Tração , Articulação do Quadril
5.
ACS Biomater Sci Eng ; 10(5): 3438-3453, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38564666

RESUMO

Despite being a weaker metal, zinc has become an increasingly popular candidate for biodegradable implant applications due to its suitable corrosion rate and biocompatibility. Previous studies have experimented with various alloy elements to improve the overall mechanical performance of pure Zn without compromising the corrosion performance and biocompatibility; however, the thermal stability of biodegradable Zn alloys has not been widely studied. In this study, TiC nanoparticles were introduced for the first time to a Zn-Al-Cu system. After hot rolling, TiC nanoparticles were uniformly distributed in the Zn matrix and effectively enabled phase control during solidification. The Zn-Cu phase, which was elongated and sharp in the reference alloy, became globular in the nanocomposite. The strength of the alloy, after introducing TiC nanoparticles, increased by 31% from 259.7 to 340.3 MPa, while its ductility remained high at 49.2% elongation to failure. Fatigue performance also improved greatly by adding TiC nanoparticles, increasing the fatigue limit by 47.6% from 44.7 to 66 MPa. Furthermore, TiC nanoparticles displayed excellent phase control capability during body-temperature aging. Without TiC restriction, Zn-Cu phases evolved into dendritic morphologies, and the Al-rich eutectic grew thicker at grain boundaries. However, both Zn-Cu and Al-rich eutectic phases remained relatively unchanged in shape and size in the nanocomposite. A combination of exceptional tensile properties, improved fatigue performance, better long-term stability with a suitable corrosion rate, and excellent biocompatibility makes this new Zn-Al-Cu-TiC material a promising candidate for biodegradable stents and other biodegradable applications.


Assuntos
Implantes Absorvíveis , Cobre , Stents , Zinco , Zinco/química , Zinco/farmacologia , Cobre/química , Cobre/farmacologia , Ligas/química , Humanos , Titânio/química , Titânio/farmacologia , Alumínio/química , Alumínio/farmacologia , Teste de Materiais , Corrosão , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Nanopartículas/química , Nanocompostos/química
6.
ACS Biomater Sci Eng ; 10(5): 3454-3469, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38590081

RESUMO

Massive unmelted Ti6Al4 V (Ti64) particles presented across all surfaces of additively manufactured Ti64 scaffolds significantly impacted the designed surface topography, mechanical properties, and permeability, reducing the osseointegration of the scaffolds. In this study, the proposed flowing acid etching (FAE) method presented high efficiency in eliminating Ti64 particles and enhancing the surface modification capacity across all surfaces of Ti64 scaffolds. The Ti64 particles across all surfaces of the scaffolds were completely removed effectively and evenly. The surface topography of the scaffolds closely resembled the design after the 75 s FAE treatment. The actual elastic modulus of the treated scaffolds (3.206 ± 0.040 GPa) was closer to the designed value (3.110 GPa), and a micrometer-scale structure was constructed on the inner and outer surfaces of the scaffolds after the 90 s FAE treatment. However, the yield strength of scaffolds was reduced to 89.743 ± 0.893 MPa from 118.251 ± 0.982 MPa after the 90 s FAE treatment. The FAE method also showed higher efficiency in decreasing the roughness and enhancing the hydrophilicity and surface energy of all of the surfaces. The FAE treatment improved the permeability of scaffolds efficiently, and the permeability of scaffolds increased to 11.93 ± 0.21 × 10-10 mm2 from 8.57 ± 0.021 × 10-10 mm2 after the 90 s FAE treatment. The treated Ti64 scaffolds after the 90 s FAE treatment exhibited optimized osseointegration effects in vitro and in vivo. In conclusion, the FAE method was an efficient way to eliminate unmelted Ti64 particles and obtain ideal surface topography, mechanical properties, and permeability to promote osseointegration in additively manufactured Ti64 scaffolds.


Assuntos
Ligas , Osseointegração , Propriedades de Superfície , Alicerces Teciduais , Titânio , Titânio/química , Ligas/química , Osseointegração/efeitos dos fármacos , Animais , Alicerces Teciduais/química , Módulo de Elasticidade , Teste de Materiais
7.
ACS Biomater Sci Eng ; 10(5): 2935-2944, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38627890

RESUMO

Ti-Au intermetallic-based material systems are being extensively studied as next-generation thin film coatings to extend the lifetime of implant devices. These coatings are being developed for application to the articulating surfaces of total joint implants and, therefore, must have excellent biocompatibility combined with superior mechanical hardness and wear resistance. However, these key characteristics of Ti-Au coatings are heavily dependent upon factors such as the surface properties and temperature of the underlying substrate during thin film deposition. In this work, Ti3Au thin films were deposited by magnetron sputtering on both glass and Ti6Al4V substrates at an ambient and elevated substrate temperature of 275 °C. These films were studied for their mechanical properties by the nanoindentation technique in both variable load and fixed load mode using a Berkovich tip. XRD patterns and cross-sectional SEM images detail the microstructure, while AFM images present the surface morphologies of these Ti3Au thin films. The biocompatibility potential of the films is assessed by cytotoxicity tests in L929 mouse fibroblast cells using Alamar blue assay, while leached ion concentrations in the film extracts are quantified using ICPOEMS. The standard deviation for hardness of films deposited on glass substrates is ∼4 times lower than that on Ti6Al4V substrates and is correlated with a corresponding increase in surface roughness from 2 nm for glass to 40 nm for Ti6Al4V substrates. Elevating substrate temperature leads to an increase in film hardness from 5.1 to 8.9 GPa and is related to the development of a superhard ß phase of the Ti3Au intermetallic. The standard deviation of this peak mechanical hardness value is reduced by ∼3 times when measured in fixed load mode compared to the variable load mode due to the effect of nanoindentation tip penetration depth. All tested Ti-Au thin films also exhibit excellent biocompatibility against L929 fibroblast cells, as viability levels are above 95% and leached Ti, Al, V, and Au ion concentrations are below 0.1 ppm. Overall, this work demonstrates a novel Ti3Au thin film system with a unique combination of high hardness and excellent biocompatibility with potential to be developed into a new wear-resistant coating to extend the lifetime of articulating total joint implants.


Assuntos
Ligas , Vidro , Teste de Materiais , Propriedades de Superfície , Titânio , Titânio/química , Ligas/química , Animais , Camundongos , Vidro/química , Materiais Revestidos Biocompatíveis/química , Linhagem Celular , Fibroblastos/efeitos dos fármacos , Materiais Biocompatíveis/química , Dureza , Ouro/química
8.
Colloids Surf B Biointerfaces ; 238: 113880, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38581836

RESUMO

In the field of orthopedics, it's crucial to effectively slow down the degradation rate of Mg alloys. This study aims to improve the degradation behavior of Mg-Zn-Ca alloys by electrodepositing fluorohydroxyapatite (FHA). We investigated the microstructure and bond strength of the deposition, as well as degradation and cellular reactions. After 15-30 days of degradation in Hanks solution, FHA deposited alloys showed enhanced stability and less pH change. The strong interfacial bond between FHA and the Mg-Zn-Ca substrate was verified through scratch tests (Critical loads: 10.73 ± 0.014 N in Mg-Zn-0.5Ca alloys). Cellular studies demonstrated that FHA-coated alloys exhibited good cytocompatibility and promoted the growth of MC3T3-E1 cells. Further tests showed FHA-coated alloys owed improved early bone mineralization and osteogenic properties, especially in Mg-Zn-0.5Ca. This research highlighted the potential of FHA-coated Mg-Zn-0.5Ca alloys in orthopedics applications.


Assuntos
Ligas , Cálcio , Magnésio , Zinco , Ligas/química , Ligas/farmacologia , Corrosão , Animais , Zinco/química , Zinco/farmacologia , Magnésio/química , Camundongos , Cálcio/química , Cálcio/metabolismo , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Propriedades de Superfície , Teste de Materiais , Proliferação de Células/efeitos dos fármacos , Hidroxiapatitas/química , Linhagem Celular , Durapatita/química , Durapatita/farmacologia
9.
Colloids Surf B Biointerfaces ; 238: 113891, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38615392

RESUMO

The three-dimensional-printed Ti6Al4V implant (3DTi) has been widely accepted for the reconstruction of massive bone defects in orthopedics owing to several advantages, such as its tailored shape design, avoiding bone graft and superior bone-implant interlock. However, the osteoinduction activity of 3DTi is inadequate when applied clinically even though it exhibits osteoconduction. This study developes a comprehensive coatless strategy for the surface improvement of 3DTi through copper (Cu) ion implantation and ultraviolet (UV) photofunctionalization to enhance osteoinductivity. The newly constructed functional 3DTi (UV/Ti-Cu) achieved stable and controllable Cu doping, sustained Cu2+ releasing, and increased surface hydrophilicity. By performing cellular experiments, we determined that the safe dose range of Cu ion implantation was less than 5×1016 ions/cm2. The implanted Cu2+ enhanced the ALP activity and the apatite formation ability of bone marrow stromal cells (BMSCs) while slightly decreasing proliferation ability. When combined with UV photofunctionalization, cell adhesion and proliferation were significantly promoted and bone mineralization was further increased. Meanwhile, UV/Ti-Cu was conducive to the migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro, theoretically facilitating vascular coupling osteogenesis. In conclusion, UV/Ti-Cu is a novel attempt to apply two coatless techniques for the surface modification of 3DTi. In addition, it is considered a potential bone substrate for repairing bone defects.


Assuntos
Ligas , Adesão Celular , Cobre , Células Endoteliais da Veia Umbilical Humana , Neovascularização Fisiológica , Osteogênese , Impressão Tridimensional , Titânio , Raios Ultravioleta , Titânio/química , Titânio/farmacologia , Ligas/química , Ligas/farmacologia , Osteogênese/efeitos dos fármacos , Cobre/química , Cobre/farmacologia , Adesão Celular/efeitos dos fármacos , Humanos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Animais , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Propriedades de Superfície , Íons/química , Proliferação de Células/efeitos dos fármacos , Próteses e Implantes , Células Cultivadas , Angiogênese
10.
Int J Med Sci ; 21(5): 958-964, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38617003

RESUMO

Nowadays dog bite is becoming a world public health problem. Therefore, the study aimed to develop a dog bite animal model that is helpful to solve these problems. In this study, the skull of an adult dog was scanned. The three-dimensional model of the dog maxillofacial bones and dentition was built by MIMICS. Next, the model was printed with Co-Cr alloy by using selective laser sintering technology to develop the dog bite simulation pliers. Then, to simulate dog bite to most, the maximum bite force of the pliers was measured and actions contained in dog bite process was analyzed. Afterwards, according to action analysis results, rabbits were bitten by the prepared instrument in actions that simulate dog's bite. Finally, the reproducibility and controllability of this animal model of dog bite injuries was validated in an in vivo study. The results showed a reliable animal model of dog bite injuries has been developed in this study. The sites and severities of the injuries could be adjusted as the operator wishes and the animal model of dog bite injuries was highly repeatable. This study also indicates the feasibility of using digital technology in establishing animal bite models.


Assuntos
Mordeduras e Picadas , Crânio , Cães , Animais , Coelhos , Reprodutibilidade dos Testes , Ligas , Modelos Animais
11.
Biosensors (Basel) ; 14(4)2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38667165

RESUMO

The exploration into nanomaterial-based nonenzymatic biosensors with superb performance in terms of good sensitivity and anti-interference ability in disease marker monitoring has always attained undoubted priority in sensing systems. In this work, we report the design and synthesis of a highly active nanocatalyst, i.e., palladium and platinum nanoparticles (Pt&Pd-NPs) decorated ultrathin nanoporous gold (NPG) film, which is modified on a homemade graphene paper (GP) to develop a high-performance freestanding and flexible nanohybrid electrode. Owing to the structural characteristics the robust GP electrode substrate, and high electrochemically catalytic activities and durability of the permeable NPG support and ultrafine and high-density Pt&Pd-NPs on it, the resultant Pt&Pd-NPs-NPG/GP electrode exhibits excellent sensing performance of low detection limitation, high sensitivity and anti-interference capability, good reproducibility and long-term stability for the detection of small molecular biomarkers hydrogen peroxide (H2O2) and glucose (Glu), and has been applied to the monitoring of H2O2 in different types of live cells and Glu in body fluids such as urine and fingertip blood, which is of great significance for the clinical diagnosis and prognosis in point-of-care testing.


Assuntos
Biomarcadores , Técnicas Biossensoriais , Técnicas Eletroquímicas , Ouro , Grafite , Nanopartículas Metálicas , Paládio , Platina , Grafite/química , Ouro/química , Platina/química , Paládio/química , Nanopartículas Metálicas/química , Biomarcadores/urina , Humanos , Peróxido de Hidrogênio , Ligas/química , Glucose/análise , Eletrodos , Papel
12.
ACS Appl Mater Interfaces ; 16(17): 21653-21664, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38644787

RESUMO

Analogous to thermal ablation techniques in clinical settings, cell necrosis induced during tumor photothermal therapy (PTT) can provoke an inflammatory response that is detrimental to the treatment of tumors. In this study, we employed a straightforward one-step liquid-phase reduction process to synthesize uniform RhRe nanozymes with an average hydrodynamic size of 41.7 nm for non-inflammatory photothermal therapy. The obtained RhRe nanozymes showed efficient near-infrared (NIR) light absorption for effective PTT, coupled with a remarkable capability to scavenge reactive oxygen species (ROS) for anti-inflammatory treatment. After laser irradiation, the 4T1 tumors were effectively ablated without obvious tumor recurrence within 14 days, along with no obvious increase in pro-inflammatory cytokine levels. Notably, these RhRe nanozymes demonstrated high biocompatibility with normal cells and tissues, both in vitro and in vivo, as evidenced by the lack of significant toxicity in female BALB/c mice treated with 10 mg/kg of RhRe nanozymes over a 14 day period. This research highlights RhRe alloy nanoparticles as bioactive nanozymes for non-inflammatory PTT in tumor therapy.


Assuntos
Ligas , Camundongos Endogâmicos BALB C , Terapia Fototérmica , Rênio , Ródio , Animais , Ródio/química , Ródio/farmacologia , Camundongos , Ligas/química , Ligas/farmacologia , Feminino , Rênio/química , Rênio/farmacologia , Linhagem Celular Tumoral , Humanos , Espécies Reativas de Oxigênio/metabolismo
13.
Int J Biol Macromol ; 267(Pt 2): 131481, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38599431

RESUMO

We developed an effective and eco-friendly strategy using chitosan gel-molten salt to achieve high loading (2.23 At. %) of single Fe-NX as assistive active sites. These sites were combined with small NiCo alloy NPs distributed on porous carbon aerogels to boost the ORR performance. The FeSAs-NiCo alloy@N-C sphere exhibits exceptional mass activity and specific activity of 3.705 A.mg-1 and 8.79 mA.cm-2(ECSA), respectively, at 0.85 V versus RHE. It has a superior onset potential of 1.08 V versus RHE, surpassing that of its nanoparticle Fe counterpart and NiCo alloy@N-C sphere. The significant improvement in ORR performance of the FeSAs-NiCo alloy@N-C sphere could be attributed to the positive effects of increased lattice strain due to the single atoms of Fe-NX hybridized with small NiCo alloy NPs. The chitosan gel-assisted molten salt strategy and assistive active sites of Fe-NX hybridized with NiCo alloy NPs regulate the electronic properties of the FeSAs-NiCo alloy@N-C sphere, both geometrically via lattice strain mismatch and electronically through shifting of the d-band center. This could influence the binding energies for oxygen and/or oxygen reduction intermediate adsorption/desorption. The additional improvement in the ORR performance of the FeSAs-NiCo alloy@N-C sphere also benefits from having a lower electrochemical activation energy.


Assuntos
Ligas , Quitosana , Géis , Oxirredução , Oxigênio , Quitosana/química , Oxigênio/química , Ligas/química , Géis/química , Ferro/química , Nanopartículas Metálicas/química , Níquel/química , Cobalto/química , Catálise , Sais/química
14.
Sensors (Basel) ; 24(7)2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38610453

RESUMO

Nanozymes possess major advantages in catalysis and biosensing compared with natural nanozymes. In this study, the AuPt@BaTiO3 bimetallic alloy Schottky junction is prepared to act as oxidase mimetics, and its photo-piezoelectric effect is investigated. The synergy between the photo-piezoelectric effect and the local surface plasmon resonance enhances the directional migration and separation of photogenerated electrons, as well as hot electrons induced by the AuPt bimetallic alloy. This synergy significantly improves the oxidase-like activity. A GSH colorimetric detection platform is developed based on this fading principle. Leveraging the photo-piezoelectric effect allows for highly sensitive detection with a low detection limit (0.225 µM) and reduces the detection time from 10 min to 3 min. The high recovery rate (ranging from 99.91% to 101.8%) in actual serum detection suggests promising potential for practical applications. The development of bimetallic alloy heterojunctions presents new opportunities for creating efficient nanozymes.


Assuntos
Ligas , Colorimetria , Catálise , Elétrons , Ressonância de Plasmônio de Superfície
15.
Skin Res Technol ; 30(4): e13687, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38566505

RESUMO

BACKGROUND: The physical appearance of an individual plays a primary role as it influences the opinion of the viewer. For this reason, orthodontic therapy to improve perceived aesthetics is in high demand among patients. This factor, combined with the increase in the number of non-invasive facial aesthetic treatments, has led to the need to understand potential risk factors in the application of medical devices to the perioral skin in patients with fixed orthodontic appliances. The aim of this study was to evaluate in vitro heating of the orthodontic bracket following electromagnetic fields and negative pressure (V-EMF) used as an anti-aging treatment. METHODS: Two different types of titanium alloy wires, one made of "beta-Titanium" alloy and the other "Ni-Ti" (DW Lingual Systems GmbH-Bad Essen-Germany) were used. The orthodontic wires and brackets mounted on a resin mouth were covered with porcine muscle tissue, then subjected to anti-aging therapy with a Bi-one LifeTouchTherapy medical device (Expo Italia Srl-Florence-Italy) which generates a combination of vacuum and electromagnetic fields (V-EMF) already adopted for antiaging therapy. During administration of the therapy, the orthodontic brackets and porcine tissue were thermally monitored using a Wavetek Materman TMD90 thermal probe (Willtek Communications GmbH-Germany). In total 20 orthodontic mouths were used, 10 with Beta Titanium wires and 10 with Nickel Titanium wires. RESULTS: A temperature increase of about 1°C was recorded in each group. The outcome of the present research shows that the absolute temperatures measured on orthodontic appliances, which, despite having a slightly different curve, both show an increase in temperature of 1.1°C at the end of the session, thus falling well within the safety range of 2°C as specified by the standard CENELEC EN 45502-1. Therefore, V-EMF therapy can be considered safe for the entire dental system and for metal prostheses, which tend to heat up at most as much as biological tissue (+0.9°C/1.1°C vs. 1.1°C/1.1°C). CONCLUSION: In conclusion, anti-aging therapy with V-EMF causes a thermal increase on orthodontic brackets that is not harmful to pulp health.


Assuntos
Campos Eletromagnéticos , Níquel , Titânio , Humanos , Animais , Suínos , Vácuo , Calefação , Fios Ortodônticos , Ligas , Teste de Materiais
16.
Anal Methods ; 16(16): 2496-2504, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38578053

RESUMO

This work describes an electrochemical sensor for the fast noninvasive detection of uric acid (UA) in saliva. The sensing material was based on a cobalt-containing Prussian blue analogue (Na2-xCo[Fe(CN)6]1-y, PCF). By optimizing the ratio of Co and Fe as 1.5 : 1 in PCF (PCF1.5,0), particles with a regular nanocubic morphology were formed. The calcination of PCF1.5,0 produced a carbon-coated CoFe alloy (CCF1.5), which possessed abundant defects and achieved an excellent electrochemical performance. Subsequently, CCF1.5 was modified on a screen-printed carbon electrode (SPCE) to fabricate the electrochemical sensor, CCF1.5/SPCE, which showed a sensitive and selective response toward salivary UA owing to its good conductivity, sufficient surface active sites and efficient catalytic activity. The determination of UA in artificial saliva achieved the wide linear range of 40 nM-30 µM and the low limit of detection (LOD) of 15.3 nM (3σ/s of 3). The performances of the sensor including its reproducibility, stability and selectivity were estimated to be satisfactory. The content of UA in human saliva was determined and the recovery was in the range of 98-107% and the total RSD was 4.14%. The results confirmed the reliability of CCF1.5/SPCE for application in noninvasive detection.


Assuntos
Ligas , Carbono , Cobalto , Técnicas Eletroquímicas , Ferrocianetos , Ácido Úrico , Ácido Úrico/química , Ácido Úrico/análise , Ferrocianetos/química , Cobalto/química , Carbono/química , Humanos , Técnicas Eletroquímicas/métodos , Ligas/química , Ferro/química , Limite de Detecção , Nanopartículas Metálicas/química , Saliva/química , Reprodutibilidade dos Testes , Eletrodos
17.
PLoS One ; 19(4): e0297943, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38669274

RESUMO

After adopting a combined approach of data-driven methods and machine learning, the prediction of material performance and the optimization of composition design can significantly reduce the development time of materials at a lower cost. In this research, we employed four machine learning algorithms, including linear regression, ridge regression, support vector regression, and backpropagation neural networks, to develop predictive models for the electrical performance data of titanium alloys. Our focus was on two key objectives: resistivity and the temperature coefficient of resistance (TCR). Subsequently, leveraging the results of feature selection, we conducted an analysis to discern the impact of alloying elements on these two electrical properties.The prediction results indicate that for the resistivity data prediction task, the radial basis function kernel-based support vector machine model performs the best, with a correlation coefficient above 0.995 and a percentage error within 2%, demonstrating high predictive capability. For the TCR data prediction task, the best-performing model is a backpropagation neural network with two hidden layers, also with a correlation coefficient above 0.995 and a percentage error within 3%, demonstrating good generalization ability. The feature selection results using random forest and Xgboost indicate that Al and Zr have a significant positive effect on resistivity, while Al, Zr, and V have a significant negative effect on TCR. The conclusion of the composition optimization design suggests that to achieve both high resistivity and TCR, it is recommended to set the Al content in the range of 1.5% to 2% and the Zr content in the range of 2.5% to 3%.


Assuntos
Ligas , Aprendizado de Máquina , Redes Neurais de Computação , Titânio , Ligas/química , Titânio/química , Algoritmos , Metais/química , Temperatura , Máquina de Vetores de Suporte
18.
Medicine (Baltimore) ; 103(17): e38004, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38669369

RESUMO

This paper demonstrates a digital manufacturing technique of a removable orthodontic appliance from an intraoral scan. An intraoral scan was made for the maxillary and mandibular arches. 3Shape Orthodontics Appliance Designer produced the virtual Hawley retainer, consisting of alloy components (Adam Clasps and Fitted Labial bow) and a base plate. The base plate design was modified to adapt to inserting the alloy components, which were combined using cold-cured acrylic. The finished Hawley retainer was assessed intraorally. The described technique emphasizes the design specifications of digitally designed and manufactured removable orthodontic appliances. A combination of additive and subtractive techniques was successfully employed to manufacture the alloy components and base plate. This novel method provides an alternative approach to manufacturing removable appliances with computer-aided design (CAD)/computer-aided manufacturing (CAM) technologies. The described process offers a precursor to digital manufacturing of other developed designs of dental appliances.


Assuntos
Desenho Assistido por Computador , Impressão Tridimensional , Humanos , Desenho de Aparelho Ortodôntico , Polímeros , Benzofenonas , Polietilenotereftalatos , Cetonas , Ligas , Aparelhos Ortodônticos Removíveis
19.
J Adhes Dent ; 26(1): 93-102, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38602286

RESUMO

PURPOSE: To investigate the influence of contamination and different cleaning methods on resin bonding to cobalt-chro- mium (CoCr) alloy disks. MATERIALS AND METHODS: A total of 160 CoCr disks were divided into 3 groups. The first group (N = 64) was air abraded with alumina particles and contaminated with a silicone disclosing agent and saliva; the second group (N = 64) was air abraded but not contaminated; the third group (N = 32) was neither air abraded nor contaminated. The first two groups were di- vided into 4 subgroups (N = 16) according to the cleaning method: ultrasonic bath in 99% isopropanol, use of a cleaning suspension of zirconium oxide particles, use of a cleaning suspension based on 10-MDP salt, and treatment with atmo- spheric plasma. The third group was divided into 2 subgroups (N = 16): treatment with atmospheric plasma and no treat- ment. All CoCr specimens were bonded to plexiglas tubes filled with a bonding resin that contained phosphate monomer. Tensile bond strength (TBS) was examined by tensile testing after 3 and 150 days of water storage plus 37,500 thermal cy- cles (N = 8). RESULTS: After contamination, TBS was significantly reduced after 150 days of water storage. Groups without air abrasion showed initially low TBS and debonded spontaneously after 150 days of water storage. CONCLUSION: None of the cleaning methods was able to remove saliva and silicone disclosing agent on CoCr-alloy sur- faces. Surface activation by plasma treatment has no long-term effect on the bond strength.


Assuntos
Resinas Compostas , Colagem Dentária , Cimentos de Resina , Ligas , Abrasão Dental por Ar , Propriedades de Superfície , Água , Resistência à Tração , Silicones , Teste de Materiais , Zircônio , Análise do Estresse Dentário
20.
PLoS One ; 19(4): e0300132, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38626176

RESUMO

Metal cutting has been extensively studied over the years for improving its efficacy, yet, parasitic mechanisms like chatter and tool wear continue to generate higher forces and energy consumption with poor surface integrity. To address these parasitic mechanisms, a single-point turning cutter design is proposed based on the physics-of-machining including chatter theory to achieve reduced power consumption during the cutting of various metallic alloys like Al-6061, Ti-6Al-4V and others used by critical sectors such as aerospace and automotive. The current work focuses on aspects of machining that effectively reduce parasitic forces feeding into cutting power. The proposed cutter amalgamates features such as optimum side and end cutting edge angles, smaller nose radius and textured rake face into the cutter-body. Such a design is further proposed for use with a mechanochemical effect on a recently discovered plastic flow mode called sinuous flow, which has been reported to bring down cutting forces significantly. Experimental and analytical tests on the cutter design features validate reduction of cutting forces and through that alleviate the tendency to chatter as well as bring about energy savings for cutting of Al 6061. The potential for reduced real-time power consumption makes this design-framework significant for multipoint milling cutters too. It will greatly facilitate frugal manufacturing to account for sustainability in manufacturing operations.


Assuntos
Ligas , Comércio , Renda , Física , Extremidade Superior
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