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1.
J Biomed Mater Res B Appl Biomater ; 111(1): 127-139, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36066321

RESUMO

Ferroalloy has shown potential as implant materials, but little attention has been paid to their effects on synovial tissue ferroptosis. This study aimed to examine the mechanical properties, degradability and biocompatibility of Fe-30Mn-0.6N alloy and effects of it on synovial tissue ferroptosis. Tensile testing showed that Fe-30Mn-0.6N alloys exhibited tensile strength of 487 ± 18 MPa, yield strength of 221 ± 10 MPa, elongation of 16.9 ± 0.3% and Young's modulus of 37.7 ± 1.3 GPa. In vivo experiments, the cross-sectional area of the Fe-30Mn-0.6N alloys decreased by 73.32 ± 12.73% after 8 weeks of implantation. The results of scanning electron microscopy (SEM) and surface elemental analysis (EDS) showed that the Fe-30Mn-0.6N alloys had more Ca, O, C and P element deposition (p < .05). After 2, 4 and 8 weeks of implantation, no inflammatory response was observed in peri-implant synovial tissue of Fe-30Mn-0.6N and Ti-6Al-4V alloys, and Fe-30Mn-0.6N alloys did not affect the expression of the ferroptosis inhibitory gene Glutathione peroxidase 4 (GPX4). Compared with the control group, 30% Fe-30Mn-0.6N alloy extracts did not affect the cell viability (p > .05) in vitro, and intracellular Fe2+ and the reactive oxygen species (ROS) was significantly reduced (p < .05). WB and PCR results showed that the 30% extracts increased the protein activity and mRNA expression of GPX4, FTH1 and SLC7A11 in synoviocytes, but had no effect on PTGS2 and p53. It is concluded that Fe-30Mn-0.6N had degradability and biocompatibility in peri-implant synovial tissue, and did not induce significantly ferroptosis in synoviocytes.


Assuntos
Ferroptose , Sinoviócitos , Teste de Materiais/métodos , Ligas/farmacologia , Titânio/farmacologia , Resistência à Tração , Materiais Biocompatíveis/farmacologia
2.
J Biomed Mater Res B Appl Biomater ; 111(1): 7-15, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35796311

RESUMO

Small fracture treatment includes the use of so-called "Herbert screws". In the past years, novel resorbable materials were introduced as an alternative to the classical titanium implants. The purpose of this study was to evaluate the influence of ongoing resorption/corrosion processes on the mechanical stability screws made from the magnesium alloy MgYREZr®. Our samples consisted of two partly resorbed screws, explanted due to medical reasons after 6 and 12 weeks, respectively, and five unused reference screws. We performed three-point bending tests to determine the stability of all screws. Additionally, with FE-models of the screws based on µCT-scans, we investigated whether any differences in the bending behavior of the screws can be attributed to the reduction of the material volume due to resorption alone. Both partly resorbed screws failed at a lower force than the reference screws (178.6 ± 5.5 N for the reference screws, 72.5 N and 74.5 N for the screw explanted after 6 and 12 weeks, respectively). FE simulations performed with the three different geometries and original material parameters (Young's modulus Enew  = 45 GPa, yield limit σnew  = 235 MPa) showed that the early fracture could not be attributed to the changed geometry alone. Material parameters for the partly resorbed screws were determined by fitting the numerical to the experimental force-displacement curves (E6week  = 15 GPa, σ6week  = 135 MPa and E12week  = 8 GPa, σ12week  = 135 MPa, respectively). Our results showed that both geometry of the screws and different material properties contribute to the overall stability. Understanding and controlling these two factors throughout the resorption process could enhance treatment options.


Assuntos
Ligas , Magnésio , Parafusos Ósseos , Implantes Absorvíveis , Titânio
3.
J Biomed Mater Res A ; 111(1): 60-70, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36125179

RESUMO

Limited material transport, causing gas cavities formation, is commonly observed during the degradation of magnesium implants, yet its effects on corrosion are not understood. Herein, a bespoke cell was designed, allowing for the incorporation of an additional agarose layer above the corroding magnesium sample. This design replicates the limited material transport in vitro and enables us to understand its influence on corrosion of magnesium alloys. This work investigated the influence of varying thickness of agarose (0-0.9 mm) on the corrosion of Mg-Zn-Zr magnesium alloy maintained at 37°C in phosphate-buffered saline (PBS). The introduction of agarose slowed transport of material away from the corroding magnesium surface, including the evolved hydrogen forming a gas cavity. It has been found that an initial increase in the agarose thickness (or the reduction in material transport) of 0.3 mm leads to an increase in the corrosion rate of the magnesium alloy by 62%. However, with a further increase in agarose thickness from 0.3 to 0.9 mm, the corrosion rate decreases by 37%. This observation has been attributed to the accumulation of, and competition between, chloride and hydroxide ions near the alloy's surface. In the presence of materials barrier, hydrogen measurement is no longer a reliable method for the measurement of corrosion rates. This study underscores the importance of the consideration of limited material transport during the in vitro corrosion tests of biomedical implants.


Assuntos
Ligas , Magnésio , Corrosão , Hidrogênio , Sefarose , Teste de Materiais
4.
J Hazard Mater ; 442: 130000, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36137886

RESUMO

Rational tailoring of hollow and porous bimetallic structures with excellent electrocatalytic performance is appealing yet challenging. Further, combining independent bimetallic nanoparticles with flexible two-dimensional substrate by forming stable heterocomplex is still highly desired for electrocatalysis. Herein, hierarchical PtCu alloy octahedrons with hollow interiors and nanosheet-assembled nanoshells were synthesized by a facile and efficient chemical transformation strategy using Cu2O as sacrificial templates. Such octahedral PtCu nanocages displayed significantly enhanced electrocatalytic activity owing to their unique hollow and porous architectures which provided easy access for analytes to the catalyst surface. Thereafter, introduction of Ti3C2Tx MXene was realized via simple incubation of Ti3C2Tx in solution containing the 3-aminopropyltriethoxysilane-capped PtCu, and their electrostatic interaction guaranteed the firm adsorption of PtCu nanocages on Ti3C2Tx nanosheets. It turned out that the sensitivity of the hybrid sensor was remarkably improved for electrochemical monitoring of endocrine disrupting pollutants in water, exhibiting ultrawide linear ranges and sub-nanomole detection limits. The eminent electrode performance is attributed to the high specific area, fast electrochemical kinetics, decent electrical catalytic ability, and the synergistic effect between Pt, Cu, and MXene.


Assuntos
Poluentes Ambientais , Cobre/química , Eletrodos , Ligas/química , Água
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 285: 121918, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36179569

RESUMO

An easy and reliable method is optimized for extractive spectrophotometric assessment of platinum(IV) with 4-(4'-nitrobenzylideneimino)-3-methyl-5-mercapto-1,2,4-triazole as an extractant. The basis of this method is the formation of red platinum(IV) complex with the above reagent in acetate buffer medium (pH 5.0) and extraction in chloroform. Good linearity with regression equation as y = 1.011 × 104 ×  + 0.002 having correlation coefficient (R2) of 0.998 over concentration up to 17.5 µg mL-1 of platinum(IV) was achieved with apparent molar absorptivity of 1.011 × 104 L mol-1 cm-1. The limit of detection (0.22 µg mL-1), limit of quantification (0.73 µg mL-1) and Sandell's sensitivity (0.0193 µg cm-2) were also estimated. The interference of various cations was removed by using proper masking agents and consequently by using EDTA and citrate to mask certain transition metals, the method becomes highly specific for platinum(IV), including the effects of platinum group metals. The method is effectively used for determination of platinum(IV) from environmental and real samples such as alloys, catalysts, thermocouple wire and pharmaceutical sample.


Assuntos
Cisplatino , Platina , Espectrofotometria/métodos , Ligas , Indicadores e Reagentes
6.
Acta Chir Orthop Traumatol Cech ; 89(5): 370-375, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36322038

RESUMO

PURPOSE OF THE STUDY Nitinol (NiTi) is a biomaterial widely used in medicine based on super-elastic and shape memory properties. miR-124 has a key role in inflammatory process, osteoblasts differentiation, and mineralization. The aim of study was evaluating the differences in gene expression of miR-124 of human physiological osteoblasts (HOB) and human osteoarthritic osteoblasts (OSBA) as a response to NiTi alloy in different heat treatments. MATERIAL AND METHODS The cells were cultivated with NiTi discs with/without addition of bacterial lipopolysaccharide (LPS) for 72 hours. MicroRNAs were isolated, underwent reverse transcription and were analyzed by RT-PCR. RESULTS As a response to LPS, HOB overexpressed miR-124, while in OSBA expression change did not occur. Overexpression was also observed in both cell lines as a response to hydrogen and helium treated NiTi discs. HOB expressed significantly higher amount of miR-124 than OSBA as a response to hydrogen treatment of NiTi discs. In addition, hydrogen treatment caused significantly higher expression in HOB than LPS. The combination of NiTi disc and LPS treatment in HOB didn't cause any expression changes. Comparing to LPS-only treatment, the expression in HOB with combination of LPS and alloy was significantly lower. In OSBA, the expression was increased by the combination of LPS and hydrogen disc, in case of helium disc, the expression was decreased. CONCLUSIONS In conclusion, human physiological and osteoarthritic osteoblasts respond to NiTi alloy with both surface (hydrogen and helium atmosphere) treatment by overexpression of miR-124. The effect of LPS as inflammatory modulator suggests the presence of an "anti-inflammatory preconditioning" in osteoarthritic osteoblasts, as physiological osteoblasts overexpression was significantly higher. Key words: nitinol, osteoblast, miR-124, lipopolysaccharide.


Assuntos
Lipopolissacarídeos , MicroRNAs , Humanos , Ligas/metabolismo , Ligas/farmacologia , Hélio/metabolismo , Hélio/farmacologia , Hidrogênio/metabolismo , Hidrogênio/farmacologia , Lipopolissacarídeos/farmacologia , Lipopolissacarídeos/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , MicroRNAs/farmacologia , Osteoblastos/metabolismo , Titânio , Osteoartrite/genética
7.
Biomaterials ; 290: 121857, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36326510

RESUMO

Cerebral aneurysm embolization is a therapeutic approach to prevent rupture and resultant clinical sequelae. Current, non-biodegradable metallic coils (platinum or tungsten) are the first-line choice to secure cerebral aneurysms. However, clinical studies report that up to 17% of aneurysms recur within 1 year after coiling, leading to retreatment and additional surgery. It would be ideal for the aneurysm coiling material to induce acute thrombotic occlusion, contribute to a tissue development process to fortify the degenerated vessel wall, and ultimately resorb to avoid leaving a permanent foreign body. With these properties in mind, a new fatty amide-based polyurethane urea (PHEUU) elastomer was synthesized and coated on biodegradable metallic (Mg alloy) coils to prepare a bioabsorbable cerebral saccular aneurysm embolization device. The chemical structure of PHEUU was confirmed using two-dimensional nuclear magnetic resonance spectroscopy. PHEUU showed comparable physical properties to elastomeric biodegradable polyurethanes lacking fatty amide immobilization, modest enzymatic degradation profiles in the first 8 wks, inherent antioxidant activity (>70% at 48 h), no cytotoxicity, and better protection for the underlying Mg alloy than poly(lactic-co-glycolic acid) (PLGA) against surface corrosion and cracking. Rat aortic smooth muscle cell attachment and platelet deposition were higher with the PHEUUs compared to bare or PLGA coated Mg alloy in vitro. PHEUU-coated Mg alloy coils showed the potential to design a fully bioabsorbable embolization coil amenable to clinical placement conditions based on computational mechanics modeling and blood-contacting test using an in vitro aneurysm model. In vivo studies using a mouse aneurysm model elicited comparable inflammatory cytokine expression to a commercially available platinum coil.


Assuntos
Aneurisma Intracraniano , Magnésio , Ratos , Animais , Angiografia Cerebral , Platina , Ligas , Implantes Absorvíveis , Elastômeros , Aneurisma Intracraniano/terapia , Amidas , Resultado do Tratamento
8.
Nat Commun ; 13(1): 6612, 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36329056

RESUMO

Integration of methanogens with semiconductors is an effective approach to sustainable solar-driven methanogenesis. However, the H2 production rate by semiconductors largely exceeds that of methanogen metabolism, resulting in abundant H2 as side product. Here, we report that binary metallic active sites (namely, NiCu alloys) are incorporated into the interface between CdS semiconductors and Methanosarcina barkeri. The self-assembled Methanosarcina barkeri-NiCu@CdS exhibits nearly 100% CH4 selectivity with a quantum yield of 12.41 ± 0.16% under light illumination, which not only exceeds the reported biotic-abiotic hybrid systems but also is superior to most photocatalytic systems. Further investigation reveal that the Ni-Cu-Cu hollow sites in NiCu alloys can directly supply hydrogen atoms and electrons through photocatalysis to the Methanosarcina barkeri for methanogenesis via both extracellular and intracellular hydrogen cycles, effectively turning down the H2 production. This work provides important insights into the biotic-abiotic hybrid interface, and offers an avenue for engineering the methanogenesis process.


Assuntos
Euryarchaeota , Metano , Metano/metabolismo , Methanosarcina barkeri/metabolismo , Euryarchaeota/metabolismo , Hidrogênio/metabolismo , Ligas
9.
Biomed Mater ; 17(6)2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36327451

RESUMO

Porous Nb-25Ta-25Ti alloys (60% porosity and 100-600 µm pore size) for bone implant applications were manufactured combining impregnation and sintering methods. Surfaces with porous micro-nanostructured networks on Nb-Ta-Ti alloys were successfully modified by various surface pre-treatments (acid etching, alkali-heat treatment and annealing treatment). Surface characteristics and Ca-P layer deposition behaviors of the multilevel structured porous Nb-Ta-Ti alloys were investigated by conducting various tests, including x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray, atomic force microscopy and optical contact angle measurement. In particular, bulk Nb-Ta-Ti alloys were also used as mutual control. The results demonstrated that the porous alloy exhibited a unique multilevel porous structure with macro-networks and micro-pits after pre-treatments. The surface passive TiO2/Nb2O5/Ta2O5layers on Nb-Ta-Ti alloys were partially dissolved by the corrosive attack of hydroxyl ions during alkali heat treatment. In addition, subsequent annealing treatment increased the density of the gel layers formed during alkali heat treatment. After immersion in SBF for 14 d, a continuous relatively uniform apatite layer was formed on the multilevel structured surfaces. Moreover, the mechanism of surface mineralization can be construed as electrostatic interactions between substrates and ions. Furthermore,in vitrocell culture showed that Nb-Ta-Ti alloys had a good biocompatibility and the multilevel porous structure could enhance the cellular behaviors including: cell adhesion and spreading.


Assuntos
Ligas , Nióbio , Porosidade , Titânio , Álcalis
10.
PLoS One ; 17(11): e0277415, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36395165

RESUMO

Twistocaloric cooling technology is a novel solid elastocaloric refrigeration to be promising alternatives to conventional compression refrigeration. The transient thermal characteristics of the twistocaloric-effect material and its cooling capacity are critical for this technology. A test rig of the continuous torsional refrigeration system (CTRS) using nitinol wires twisted by a stepping motor was built. The experimental tests show that, the surface temperatures increased as the stepping motor twisted the nitinol wires clockwise, and decreased by untwisting them counterclockwise under the stepping motor speed of 40, 45 and 45rpm. The maximum temperature rise and drop relative to the ambient temperature for the two-twisted-nitinol-wire combinations were 7.1 and 2.6°C, higher than those of 1.4 and 0.6°C for the single nitinol wire, respectively. An optimization program based on a heat conduction model was constructed to attain the potential cooling and heating capacities (PHCCs) of the nitinol wires. Then, PHCCs were introduced into the coupled flow and convective heat transfer model to predict the actual cooling and heating capacities of the CTRS. They were discovered to increase as the number of nitinol wires, the stepping motor speed, and the air velocity. The results can be referred in developing a continuous torsional refrigeration prototype.


Assuntos
Ligas , Refrigeração , Fios Ortopédicos , Transição de Fase
11.
Dalton Trans ; 51(45): 17441-17453, 2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36326162

RESUMO

One-pot conversion of furfural, a biomass-derived platform chemical, to gamma-valerolactone (GVL), a fuel additive and green solvent, involves multiple steps of hydrogenation. Among these reactions, the deep hydrogenation of the furan ring in furfural interrupts GVL formation over Ni or Co-based catalysts. In this study, a method of alloying Ni and Co with Fe over a ZSM-5 support was proposed for tackling excessive activity of the catalyst for hydrogenation. The results indicated that the formation of binary NiFe and CoFe alloys in Ni-Co-Fe/ZSM-5 enhanced the dispersion of metallic species, reduction of metal oxides, formation of more Lewis acidic sites, and the adsorption of the C-O functionality of the furan ring, while lowering the capability for adsorption/activation of H2 and the adsorption of the CC group of the furan ring. These factors together reduced the activity for the hydrogenation of the furan ring in furfural, but enhanced the hydrogenation of the CO in ethyl levulinate (EL). The kinetic study confirmed that the hydrogenation of EL was the rate-determining step. The coordination of the dual alloys, NiFe and CoFe, in the bifunctional Ni-Co-Fe/ZSM-5 catalyst rendered superior activity for selective one-pot conversion of furfural to GVL with a yield of 85.7%.


Assuntos
Furaldeído , Níquel , Hidrogenação , Cobalto , Ligas , Ferro , Furanos
12.
Anal Chim Acta ; 1236: 340552, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36396226

RESUMO

Spectral fluctuation is one of the main obstacles affecting the further development of LIBS, and it is also the current research hotspot and difficulty. To meet the requirements of industrial monitoring, a novel method named plasma image-spectrum fusion laser induced breakdown spectroscopy (PISF-LIBS) was proposed to correct the spectral fluctuation and improve the quantitative accuracy. In this method, by systematically analyzing the spectral radiation model, six main factors affecting the spectral stability were obtained. Further, the standard spectrum in the ideal plasma state which is not affected by these six factors was calculated, and the deviation from the actual spectrum was obtained. According to the above analysis, the calculated deviation was mainly affected by these six factors and can be estimated through them. Therefore, this study creatively proposed to use the effective information in the plasma images and spectra to indirectly characterize the deviation, so as to realize the correction of spectral fluctuation. To verify the wide applicability of PISF-LIBS in experimental conditions, the LIBS spectra of aluminum alloy obtained under four different experimental conditions were used. After PISF-LIBS correction, the R2 increased to more than 0.974, and the RMSE, MAPE and RSD of the prediction set decreased by 44.789%, 47.854% and 51.687% on average. To further verify the wide applicability of PISF-LIBS in experimental samples, alloy steel samples and pressed samples were also used. For alloy steel samples, after PISF-LIBS correction, the R2 increased to more than 0.996, and the RMSE, MAPE and RSD of the prediction set decreased by 48.337%, 52.856% and 25.819% evenly. For pressed samples, the R2 increased over 0.992, and the RMSE, MAPE and RSD of the prediction set decreased by 61.493%, 61.080% and 39.945% averagely. The experimental results prove the effectiveness and wide applicability of PISF-LIBS in spectral fluctuation correction.


Assuntos
Ligas , Lasers , Análise Espectral/métodos , Aço
13.
Int J Nanomedicine ; 17: 5469-5488, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36426372

RESUMO

Introduction: Titanium (Ti) and its alloys (eg, Ti6Al4V) are exceptional treatments for replacing or repairing bones and damaged surrounding tissues. Although Ti-based implants exhibit excellent osteoconductive performance under healthy conditions, the effectiveness and successful clinical achievements are negatively altered in diabetic patients. Concernedly, diabetes mellitus (DM) contributes to osteoblastic dysfunctionality, altering efficient osseointegration. This work investigates the beneficial osteogenic activity conducted by nanostructured TiO2 under detrimental microenvironment conditions, simulated by human diabetic serum. Methods: We evaluated the bone-forming functional properties of osteoblasts on synthesized TiO2 nanotubes (NTs) by anodization and Ti6Al4V non-modified alloy surfaces under detrimental diabetic conditions. To simulate the detrimental environment, MC3T3E-1 preosteoblasts were cultured under human diabetic serum (DS) of two diagnosed and metabolically controlled patients. Normal human serum (HS) was used to mimic health conditions and fetal bovine serum (FBS) as the control culture environment. We characterized the matrix mineralization under the detrimental conditions on the control alloy and the NTs. Moreover, we applied immunofluorescence of osteoblasts differentiation markers on the NTs to understand the bone-expression stimulated by the biochemical medium conditions. Results: The diabetic conditions depressed the initial osteoblast growth ability, as evidenced by altered early cell adhesion and reduced proliferation. Nonetheless, after three days, the diabetic damage was suppressed by the NTs, enhancing the osteoblast activity. Therefore, the osteogenic markers of bone formation and the differentiation of osteoblasts were reactivated by the nanoconfigured surfaces. Far more importantly, collagen secretion and bone-matrix mineralization were stimulated and conducted to levels similar to those of the control of FBS conditions, in comparison to the control alloy, which was not able to reach similar levels of bone functionality than the NTs. Conclusion: Our study brings knowledge for the potential application of nanostructured biomaterials to work as an integrative platform under the detrimental metabolic status present in diabetic conditions.


Assuntos
Diabetes Mellitus , Nanotubos , Humanos , Células Cultivadas , Nanotubos/química , Osteoblastos , Ligas , Diabetes Mellitus/metabolismo
14.
Medicina (Kaunas) ; 58(11)2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36363481

RESUMO

Background and Objectives: The interaction between dental alloys and saliva affects both its own properties and those of metallic materials. Materials and Methods: Samples made of Cr-Co and Ni-Cr were studied. It was opted for corrosion under tension, scanning electron microscopy was used to characterize the surface morphology, and the chemical composition of the surface was assessed with the help of an Energy Dispersive Spectrometer. In vitro testing of the cytotoxic impact of the study eluates was carried out by flow cytometric analysis. Results: Pitting areas appear in the mass of the Ni-Cr alloy. Nickel, Manganese, and Cobalt dissolve and go into the solution. Corrosion is superficial in the case of the Cr-Co alloy, the corrosion points are shallow, and the amount of dissolved metal is relatively small. Mostly Nickel passes into the solution, unlike Chromium and Cobalt, which remain at this level. We noticed an increase in the viability of cell cultures in the case of Cr-Co alloy and a decrease in the number of living cells (87%) for Ni-Cr alloy. Conclusions: Common alloys (Ni-Cr and Cr-Co) are prone to corrosion, because they lack structural features that would shield the alloy from corrosion agents.


Assuntos
Níquel , Saliva , Humanos , Níquel/química , Propriedades de Superfície , Cobalto/química , Ligas
15.
Biosensors (Basel) ; 12(11)2022 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-36421131

RESUMO

Surface plasmon-coupled emission (SPCE), a novel signal enhancement technology generated by the interactions between surface plasmons and excited fluorophores in close vicinity to metallic film, has shown excellent performance in bioimaging. Variable-angle nanoplasmonic fluorescence microscopy (VANFM), based on an SPCE imaging system, can selectively modulate the imaging depth by controlling the excitation angles. In order to further improve the imaging performance, Au-Ag alloy nanoshuttles were introduced into an Au substrate to mediate the plasmonic properties. Benefiting from the strong localized plasmon effect of the modified SPCE chip, better imaging brightness, signal-to-background ratio and axial resolution for imaging of the cell membrane region were obtained, which fully displays the imaging advantages of SPCE system. Meanwhile, the imaging signal obtained from the critical angle excitation mode was also amplified, which helps to acquire a more visible image of the cell both from near- and far-field in order to comprehensively investigate the cellular interactions.


Assuntos
Ligas , Ressonância de Plasmônio de Superfície , Ressonância de Plasmônio de Superfície/métodos , Imagem Óptica , Corantes Fluorescentes/química , Microscopia de Fluorescência/métodos
16.
Sensors (Basel) ; 22(19)2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36236319

RESUMO

The laser ultrasonic method using the characteristics of transmitted Rayleigh waves in the frequency domain to determine micro-crack depth is proposed. A low-pass filter model based on the interaction between Rayleigh waves and surface cracks is built and shows that the stop band, called the sensitive frequency range, is sensitive to the depth of surface cracks. The sum of transmission coefficients in the sensitive frequency range is defined as an evaluated parameter to determine crack depth. Moreover, the effects of the sensitive frequency range and measured distance on the evaluated results are analyzed by the finite-element method to validate the robustness of this depth-evaluating method. The estimated results of surface cracks with depths ranging from 0.08 mm to ~0.5 mm on the FEM models and aluminum-alloy samples demonstrate that the laser ultrasounds using the characteristics of Rayleigh waves in the frequency domain do work for quantitative crack depth.


Assuntos
Alumínio , Ultrassom , Ligas , Lasers , Ultrassonografia
17.
Sensors (Basel) ; 22(19)2022 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-36236764

RESUMO

Titanium-copper alloy films with stoichiometry given by Ti1-xCux were produced by magnetron co-sputtering technique and analyzed in order to explore the suitability of the films to be applied as resistive temperature sensors with antimicrobial properties. For that, the copper (Cu) amount in the films was varied by applying different DC currents to the source during the deposition in order to change the Cu concentration. As a result, the samples showed excellent thermoresistivity linearity and stability for temperatures in the range between room temperature to 110 °C. The sample concentration of Ti0.70Cu0.30 has better characteristics to act as RTD, especially the αTCR of 1990 ×10-6°C-1. The antimicrobial properties of the Ti1-xCux films were analyzed by exposing the films to the bacterias S. aureus and E. coli, and comparing them with bare Ti and Cu films that underwent the same protocol. The Ti1-xCux thin films showed bactericidal effects, by log10 reduction for both bacteria, irrespective of the Cu concentrations. As a test of concept, the selected sample was subjected to 160 h reacting to variations in ambient temperature, presenting results similar to a commercial temperature sensor. Therefore, these Ti1-xCux thin films become excellent antimicrobial candidates to act as temperature sensors in advanced coating systems.


Assuntos
Anti-Infecciosos , Titânio , Ligas , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bactérias , Cobre , Escherichia coli , Staphylococcus aureus , Temperatura
18.
PLoS One ; 17(10): e0275485, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36260552

RESUMO

Nickel-Titanium (NiTi) shape memory alloys (SMAs) are smart materials able to recover their original shape under thermal stimulus. Near-net-shape NiTi SMA foils of 2 meters in length and width of 30 mm have been successfully produced by a planar flow casting facility at CSIRO, opening possibilities of wider applications of SMA foils. The study also focuses on establishing a fully automated experimental system for the characterisation of their reversible actuation, significantly improving SMA foils adaptation into real applications. Artificial Intelligence involving Computer Vision and Machine Learning based methods were successfully employed in the development of the automation SMA characterization process. The study finds that an Extreme Gradient Boosting (XGBoost) Regression model based predictive system experimented with over 175,000 video samples could achieve 99% overall prediction accuracy. Generalisation capability of the proposed system makes a significant contribution towards the efficient optimisation of the material design to produce high quality 30 mm SMA foils.


Assuntos
Níquel , Titânio , Ligas de Memória da Forma , Inteligência Artificial , Ligas , Teste de Materiais
19.
J Orthop Surg Res ; 17(1): 445, 2022 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-36209088

RESUMO

BACKGROUND: Ultraviolet (UV) light-mediated photofunctionalization improves the osseointegration of pure titanium and titanium alloy (Ti6Al4V). However, little is known about the effect of UV irradiation on Ti6Al4V, used frequently in orthopedic surgery, in diabetic patients. We examined the effect of UV irradiation on Ti6Al4V in rats with type 2 diabetes. METHODS: Cylinder Ti6Al4V implants were used. Half the animals were Sprague Dawley rats (the control group), and the other half were Spontaneously Diabetic Torii fatty rats (the diabetes mellitus model). For radiological analysis, bone density was observed and calculated using 3D microcomputed tomography. Histological analysis was performed to calculate the bone-implant contact (BIC) ratio. We used Pearson correlation to analyze the correlation between average blood glucose level and BIC ratio, and between average blood glucose level and bone volume (BV) ratio. RESULTS: In the UV light-treated group, the BIC ratios of the normal and diabetic rats increased significantly compared with those in the untreated group at 2 weeks; at 4 weeks, the BIC ratio of the diabetic rats increased significantly, but there was no significant increase in the control animals. In both the control and diabetic groups, there was no significant difference in the BV ratios between the UV-treated and untreated implants at 2 or 4 weeks. The average blood glucose level in the 4-week group negatively correlated with the BIC and BV ratios. The average blood glucose level in the UV-treated group negatively correlated with the BIC ratio. CONCLUSION: Photofunctionalization of Ti6Al4V implants may promote osseointegration in the early stages in rats with type 2 diabetes.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Ligas , Animais , Glicemia , Osseointegração , Ratos , Ratos Sprague-Dawley , Propriedades de Superfície , Titânio , Microtomografia por Raio-X
20.
Nanoscale ; 14(39): 14789-14800, 2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36184995

RESUMO

The poor permeability of therapeutic agents across the blood-brain barrier and blood-tumor barrier is a significant barrier in glioma treatment. Low-density lipoprotein receptor-related protein (LRP-1) recognises a dual-targeting ligand, angiopep-2, which is overexpressed in the BBB and gliomas. Here, we have synthesized Ti@FeAu core-shell nanoparticles conjugated with angiopep-2 (Ti@FeAu-Ang nanoparticles) to target glioma cells and treat brain cancer via hyperthermia produced by a magnetic field. Our results confirmed that Ti@FeAu core-shell nanoparticles were superparamagnetic, improved the negative contrast effect on glioma, and exhibited a temperature elevation of 12° C upon magnetic stimulation, which implies potential applications in magnetic resonance imaging (MRI) and hyperthermia-based cancer therapy. Angiopep-2-decorated nanoparticles exhibited higher cellular uptake by C6 glioma cells than by L929 fibroblasts, demonstrating selective glioma targeting and improved cytotoxicity up to 85% owing to hyperthermia produced by a magnetic field. The in vivo findings demonstrated that intravenous injection of Ti@FeAu-Ang nanoparticles exhibited a 10-fold decrement in tumor volume compared to the control group. Furthermore, immunohistochemical analysis of Ti@FeAu-Ang nanoparticles showed that coagulative necrosis of tumor tissues and preliminary safety analysis highlighted no toxicity to the haematological system, after Ti@FeAu-Ang nanoparticle-induced hyperthermia treatment.


Assuntos
Neoplasias Encefálicas , Glioma , Nanopartículas de Magnetita , Nanopartículas , Ligas , Barreira Hematoencefálica/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/terapia , Linhagem Celular Tumoral , Diagnóstico por Imagem , Sistemas de Liberação de Medicamentos/métodos , Glioma/tratamento farmacológico , Glioma/terapia , Humanos , Ligantes , Lipoproteínas LDL , Peptídeos , Nanomedicina Teranóstica , Titânio/farmacologia
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