RESUMO
Phoxim, extensively utilized in agriculture as an organothiophosphate insecticide, has the potential to cause neurotoxicity and pose human health hazards. In this study, an electrochemical enzyme biosensor based on Ti3C2 MXene/MoS2@AuNPs/AChE was constructed for the sensitive detection of phoxim. The two-dimensional multilayer structure of Ti3C2 MXene provides a robust framework for MoS2, leading to an expansion of the specific surface area and effectively preventing re-stacking of Ti3C2 MXene. Additionally, the synergistic effect of self-reduced grown AuNPs with MoS2 further improves the electrical conductivity of the composites, while the robust framework provides a favorable microenvironment for immobilization of enzyme molecules. Ti3C2 MXene/MoS2@AuNPs electrochemical enzyme sensor showed a significant response to phoxim in the range of 1 × 10-13 M to 1 × 10-7 M with a detection limit of 5.29 × 10-15 M. Moreover, the sensor demonstrated excellent repeatability, reproducibility, and stability, thereby showing its promising potential for real sample detection.
Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Frutas , Ouro , Nanopartículas Metálicas , Nanocompostos , Compostos Organotiofosforados , Titânio , Ouro/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Nanocompostos/química , Frutas/química , Nanopartículas Metálicas/química , Técnicas Biossensoriais/instrumentação , Compostos Organotiofosforados/análise , Titânio/química , Limite de Detecção , Contaminação de Alimentos/análise , Molibdênio/química , Inseticidas/análise , Inseticidas/química , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/químicaRESUMO
Rapid screening for foodborne pathogens is crucial for food safety. A rapid and one-step electrochemical sensor has been developed for the detection of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium). Through the construction of aptamer/two-dimensional carboxylated Ti3C2Tx (2D C-Ti3C2Tx)/two-dimensional Zn-MOF (2D Zn-MOF) composites, the recognition elements, signal tags, and signal amplifiers are integrated on the electrode surface. Pathogens are selectively captured using the aptamer, which increases the impedance of the electrode surfaceï¼leads to a decrease in the 2D Zn-MOF current. Bacteria can be rapidly quantified using a one-step detection method and the replacement of aptamers. The detection limits for E. coli, S. aureus, and S. typhimurium are 6, 5, and 5 CFU·mL-1, respectively. The sensor demonstrated reliable detection capabilities in real-sample testing. Therefore, the one-step sensor based on the 2D Zn-MOF and 2D C-Ti3C2Tx has significant application value in the detection of foodborne pathogens.
Assuntos
Técnicas Eletroquímicas , Escherichia coli , Salmonella typhimurium , Staphylococcus aureus , Zinco , Staphylococcus aureus/isolamento & purificação , Salmonella typhimurium/isolamento & purificação , Zinco/análise , Escherichia coli/isolamento & purificação , Técnicas Eletroquímicas/instrumentação , Técnicas Biossensoriais/instrumentação , Estruturas Metalorgânicas/química , Microbiologia de Alimentos , Titânio/química , Limite de Detecção , Eletrodos , Contaminação de Alimentos/análiseRESUMO
The (002) crystallographic plane-oriented hydroxyapatite (HA) and anatase TiO2 enable favorable hydrophilicity, osteogenesis, and biocorrosion resistance. Thus, the crystallographic plane control in HA coating and crystalline phase control in TiO2 is vital to affect the surface and interface bioactivity and biocorrosion resistance of titanium (Ti) implants. However, a corresponding facile and efficient fabrication method is absent to realize the HA(002) mineralization and anatase TiO2 formation on Ti. Herein, we utilized the predominant Ti(0002) plane of the fibrous-grained titanium (FG Ti) to naturally form anatase TiO2 and further achieve a (002) basal plane oriented nanoHA (nHA) film through an in situ mild hydrothermal growth strategy. The formed FG Ti-nHA(002) remarkably improved hydrophilicity, mineralization, and biocorrosion resistance. Moreover, the nHA(002) film reserved the microgroove-like topological structure on FG Ti. It could enhance osteogenic differentiation through promoted contact guidance, showing one order of magnitude higher expression of osteogenic-related genes. On the other hand, the nHA(002) film restrained the osteoclast activity by blocking actin ring formation. Based on these capacities, FG Ti-nHA(002) improved new bone growth and binding strength in rabbit femur implantation, achieving satisfactory osseointegration within 2 weeks.
Assuntos
Durapatita , Osseointegração , Titânio , Titânio/química , Durapatita/química , Animais , Osseointegração/efeitos dos fármacos , Coelhos , Osteogênese/efeitos dos fármacos , Corrosão , Camundongos , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Diferenciação Celular/efeitos dos fármacosRESUMO
Cerium and cobalt loaded Co-Ce/TiO2 catalyst prepared by impregnation method was investigated for photothermal catalytic toluene oxidation. Based on catalyst characterizations (XPS, EPR and H2-TPR), redox cycle between Co and TiO2 (Co2+ + Ti4+ â Co3+ + Ti3+) results in the formation of Co3+, Ti3+ and oxygen vacancies, which play important roles in toluene catalytic oxidation reaction. The introduction of Ce brings in the dual redox cycles (Co2+ + Ti4+ â Co3+ + Ti3+, Co2+ + Ce4+ â Co3+ + Ce3+), further promoting the elevation of reaction sites amount. Under full spectrum irradiation with light intensity of 580 mW/cm2, Co-Ce/TiO2 catalyst achieved 96% of toluene conversion and 73% of CO2 yield, obviously higher than Co/P25 and Co/TiO2. Co-Ce/TiO2 efficiently maintains 10-hour stability test under water vapor conditions and exhibits better photothermal catalytic performance than counterparts under different wavelengths illumination. Photothermal catalytic reaction displays improved activities compared with thermal catalysis, which is attributed to the promotional effect of light including photocatalysis and light activation of reactive oxygen species.
Assuntos
Cério , Cobalto , Oxirredução , Titânio , Tolueno , Titânio/química , Cobalto/química , Catálise , Tolueno/química , Cério/química , Modelos Químicos , Processos FotoquímicosRESUMO
Reducing the cost of RuO2/TiO2 catalysts is still one of the urgent challenges in catalytic HCl oxidation. In the present work, a Ce-doped TiO2 supported RuO2 catalyst with a low Ru loading was developed, showing a high activity in the catalytic oxidation of HCl to Cl2. The results on some extensive characterizations of both Ce-doped TiO2 carriers and their supported RuO2 catalysts show that the doping of Ce into TiO2 can effectively change the lattice parameters of TiO2 to improve the dispersion of the active RuO2 species on the carrier, which facilitates the production of surface Ru species to expose more active sites for boosting the catalytic performance even under some harsh reaction conditions. This work provides some scientific basis and technical support for chlorine recycling.
Assuntos
Cério , Ácido Clorídrico , Oxirredução , Titânio , Titânio/química , Catálise , Cério/química , Ácido Clorídrico/química , Compostos de Rutênio/química , Cloretos/química , Modelos Químicos , Cloro/químicaRESUMO
Implant-associated infection (IAI) has become an intractable challenge in clinic. The healing of IAI is a complex physiological process involving a series of spatiotemporal connected events. However, existing titanium-based implants in clinic suffer from poor antibacterial effect and single function. Herein, a versatile surface platform based on the presentation of sequential function is developed. Fabrication of titania nanotubes and poly-γ-glutamic acid (γ-PGA) achieves the efficient incorporation of silver ions (Ag+) and the pH-sensitive release in response to acidic bone infection microenvironment. The optimized PGA/Ag platform exhibits satisfactory biocompatibility and converts macrophages from pro-inflammatory M1 to pro-healing M2 phenotype during the subsequent healing stage, which creates a beneficial osteoimmune microenvironment and promotes angio/osteogenesis. Furthermore, the PGA/Ag platform mediates osteoblast/osteoclast coupling through inhibiting CCL3/CCR1 signaling. These biological effects synergistically improve osseointegration under bacterial infection in vivo, matching the healing process of IAI. Overall, the novel integrated PGA/Ag surface platform proposed in this study fulfills function cascades under pathological state and shows great potential in IAI therapy.
Assuntos
Antibacterianos , Ácido Poliglutâmico , Prata , Titânio , Animais , Titânio/química , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Camundongos , Ácido Poliglutâmico/química , Ácido Poliglutâmico/análogos & derivados , Prata/química , Prata/farmacologia , Propriedades de Superfície , Nanotubos/química , Células RAW 264.7 , Infecções Relacionadas à Prótese/tratamento farmacológico , Osseointegração/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Osteoblastos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Cicatrização/efeitos dos fármacos , Próteses e ImplantesRESUMO
In the present study, we investigated the influence of surface fluorine (F) on TiO2 for the photocatalytic oxidation (PCO) of toluene. TiO2 modified with different F content was prepared and tested. It was found that with the increasing of F content, the toluene conversion rate first increased and then decreased. However, CO2 mineralization efficiency showed the opposite trend. Based on the characterizations, we revealed that F substitutes the surface hydroxyl of TiO2 to form the structure of Ti-F. The presence of the appropriate amount of surface Ti-F on TiO2 greatly enhanced the separation of photogenerated carriers, which facilitated the generation of ·OH and promoted the activity for the PCO of toluene. It was further revealed that the increase of only ·OH promoted the conversion of toluene to ring-containing intermediates, causing the accumulation of intermediates and then conversely inhibited the ·OH generation, which led to the decrease of the CO2 mineralization efficiency. The above results could provide guidance for the rational design of photocatalysts for toluene oxidation.
Assuntos
Fluoretos , Oxirredução , Titânio , Tolueno , Tolueno/química , Titânio/química , Catálise , Fluoretos/química , Processos Fotoquímicos , Modelos QuímicosRESUMO
In this study, non-thermal plasma (NTP) was employed to modify the Cu/TiO2 adsorbent to efficiently purify H2S in low-temperature and micro-oxygen environments. The effects of Cu loading amounts and atmospheres of NTP treatment on the adsorption-oxidation performance of the adsorbents were investigated. The NTP modification successfully boosted the H2S removal capacity to varying degrees, and the optimized adsorbent treated by air plasma (Cu/TiO2-Air) attained the best H2S breakthrough capacity of 113.29 mg H2S/gadsorbent, which was almost 5 times higher than that of the adsorbent without NTP modification. Further studies demonstrated that the superior performance of Cu/TiO2-Air was attributed to increased mesoporous volume, more exposure of active sites (CuO) and functional groups (amino groups and hydroxyl groups), enhanced Ti-O-Cu interaction, and the favorable ratio of active oxygen species. Additionally, the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results indicated the main reason for the deactivation was the consumption of the active components (CuO) and the agglomeration of reaction products (CuS and SO42-) occupying the active sites on the surface and the inner pores of the adsorbents.
Assuntos
Cobre , Sulfeto de Hidrogênio , Oxirredução , Titânio , Titânio/química , Adsorção , Cobre/química , Sulfeto de Hidrogênio/química , Poluentes Atmosféricos/química , Gases em Plasma/química , Modelos QuímicosRESUMO
The reduction of nitrobenzene to aniline is very important for both pollution control and chemical synthesis. Nevertheless, difficulties still remain in developing a catalytic system having high efficiency and selectivity for the production of aniline. Herein, it was found that PdO nanoparticles highly dispersed on TiO2 support (PdO/TiO2) functioned as a highly efficient catalyst for the reduction of nitrobenzene in the presence of NaBH4. Under favorable conditions, 95% of the added nitrobenzene (1 mmol/L) was reduced within 1 min with an ultra-low apparent activation energy of 10.8 kJ/mol by using 0.5%PdO/TiO2 as catalysts and 2 mmol/L of NaBH4 as reductants, and the selectivity to aniline even reached up to 98%. The active hydrogen species were perceived as dominant species during the hydrogenation of nitrobenzene by the results of isotope labeling experiments and ESR spectroscopic. A mechanism was proposed as follows: PdO activates the nitro groups and leads to in-situ generation of Pd, and the generated Pd acts as the reduction sites to produce active hydrogen species. In this catalytic system, nitrobenzene prefers to be adsorbed on the PdO nanoparticles of the PdO/TiO2 composite. Subsequently, the addition of NaBH4 results in in-situ generation of a Pd/PdO/TiO2 composite from the PdO/TiO2 composite, and the Pd nanoclusters would activate NaBH4 to generate active hydrogen species to attack the adsorbed nitro groups. This work will open up a new approach for the catalytic transfer hydrogenation of nitrobenzene to aniline in green chemistry.
Assuntos
Compostos de Anilina , Nitrobenzenos , Paládio , Titânio , Nitrobenzenos/química , Compostos de Anilina/química , Titânio/química , Hidrogenação , Catálise , Paládio/química , Modelos QuímicosRESUMO
The expandable graphite (EG) modified TiO2 nanocomposites were prepared by the high shear method using the TiO2 nanoparticles (NPs) and EG as precursors, in which the amount of EG doped in TiO2 was 10 wt.%. Followed by the impregnation method, adjusting the pH of the solution to 10, and using the electrostatic adsorption to achieve spatial confinement, the Pt elements were mainly distributed on the exposed TiO2, thus generating the Pt/10EG-TiO2-10 catalyst. The best CO oxidation activity with the excellent resistance to H2O and SO2 was obtained over the Pt/10EG-TiO2-10 catalyst: CO conversion after 36 hr of the reaction was ca. 85% under the harsh condition of 10 vol.% H2O and 100 ppm SO2 at a high gaseous hourly space velocity (GHSV) of 400,000 hr-1. Physicochemical properties of the catalysts were characterized by various techniques. The results showed that the electrostatic adsorption, which riveted the Pt elements mainly on the exposed TiO2 of the support surface, reduced the dispersion of Pt NPs on EG and achieved the effective dispersion of Pt NPs, hence significantly improving CO oxidation activity over the Pt/10EG-TiO2-10 catalyst. The 10 wt.% EG doped in TiO2 caused the TiO2 support to form a more hydrophobic surface, which reduced the adsorption of H2O and SO2 on the catalyst, greatly inhibited deposition of the TiOSO4 and formation of the PtSO4 species as well as suppressed the oxidation of SO2, thus resulting in an improvement in the resistance to H2O and SO2 of the Pt/10EG-TiO2-10 catalyst.
Assuntos
Grafite , Oxirredução , Platina , Dióxido de Enxofre , Titânio , Titânio/química , Grafite/química , Dióxido de Enxofre/química , Platina/química , Catálise , Monóxido de Carbono/química , Água/química , Poluentes Atmosféricos/química , Modelos QuímicosRESUMO
NH3-SCR (SCR: Selective catalytic reduction) is an effective technology for the de-NOx process from both mobile and stationary pollution sources, and the most commonly used catalysts are the vanadia-based catalysts. An innovative V2O5-CeO2/TaTiOx catalyst for NOx removal was prepared in this study. The influences of Ce and Ta in the V2O5-CeO2/TaTiOx catalyst on the SCR performance and physicochemical properties were investigated. The V2O5-CeO2/TaTiOx catalyst not only exhibited excellent SCR activity in a wide temperature window, but also presented strong resistance to H2O and SO2 at 275 â. A series of characterization methods was used to study the catalysts, including H2-temperature programmed reduction, X-ray photoelectron spectroscopy, NH3-temperature programmed desorption, etc. It was discovered that a synergistic effect existed between Ce and Ta species. The introduction of Ce and Ta enlarged the specific surface area, increased the amount of acid sites and the ratio of Ce3+, (V3++V4+) and Oα, and strengthened the redox capability which were related to synergistic effect between Ce and Ta species, significantly improving the NH3-SCR activity.
Assuntos
Amônia , Cério , Titânio , Compostos de Vanádio , Catálise , Cério/química , Titânio/química , Amônia/química , Compostos de Vanádio/química , Poluentes Atmosféricos/química , Oxirredução , Poluição do Ar/prevenção & controleRESUMO
Antibiotics are extensively used in human medicine, aquaculture, and animal husbandry, leading to the release of antimicrobial resistance into the environment. This contributes to the rapid spread of antibiotic-resistant genes (ARGs), posing a significant threat to human health and aquatic ecosystems. Conventional wastewater treatment methods often fail to eliminate ARGs, prompting the adoption of advanced oxidation processes (AOPs) to address this growing risk. The study investigates the efficacy of visible light-driven photocatalytic systems utilizing two catalyst types (TiO2-Pd/Cu and g-C3N4-Pd/Cu), with a particular emphasis on their effectiveness in eliminating blaTEM, ermB, qnrS, tetM. intl1, 16 S rDNA and 23 S rDNA through photocatalytic ozonation and peroxone processes. Incorporating O3 into photocatalytic processes significantly enhances target removal efficiency, with the photocatalyst-assisted peroxone process emerging as the most effective AOP. The reemergence of targeted contaminants following treatment highlights the pivotal importance of AOPs and the meticulous selection of catalysts in ensuring sustained treatment efficacy. Furthermore, Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analysis reveals challenges in eradicating GC-rich bacteria with TiO2 and g-C3N4 processes, while slight differences in Cu/Pd loadings suggest g-C3N4-based ozonation improved antibacterial effectiveness. Terminal Restriction Fragment Length Polymorphism analysis highlights the efficacy of the photocatalyst-assisted peroxone process in treating diverse samples.
Assuntos
Titânio , Titânio/química , Titânio/farmacologia , Catálise , Águas Residuárias/microbiologia , Águas Residuárias/química , Antibacterianos/farmacologia , Antibacterianos/química , Purificação da Água/métodos , Ozônio/química , Ozônio/farmacologia , Resistência Microbiana a Medicamentos/genética , Compostos de Nitrogênio/química , Luz , Nitrilas/química , Nitrilas/farmacologia , Cobre/química , Cobre/farmacologia , Genes Bacterianos , Farmacorresistência Bacteriana/genética , Oxirredução , GrafiteRESUMO
The emergence of Multidrug-resistant (MDR) bacteria are becoming a major worldwide health concern, encouraging the development effective alternatives to conventional antibiotics. The study identified P. aeruginosa and assessed its antimicrobial sensitivity using the Vitek-2 system. Carbapenem-resistant genes were detected through Polymerase chain reaction (PCR). MDR- P. aeruginosa isolates were used to biosynthesize titanium dioxide nanoparticles (TiO2NPs) and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM). A study involving 78 P. aeruginosa isolates revealed that 85.8% were MDR, with meropenem and amikacin showing effectiveness against 70% of the isolates. The most prevalent carbapenemase gene was blaOXA-48, present in 83% of the isolates. Majority of the isolates formed biofilms, and biosynthesized TiO2NPs were able to reduce biofilm formation by 94%. TiO2NPs exhibited potent antibacterial action against MDR-Gram-negative bacilli pathogens and showed synergistic activity with antibiotics, particularly piperacillin, with a significant fold increase in areas (283%). A new local strain of P. aeruginosa, identified as ON678251 in the World GenBank, was found capable of producing TiO2NPs. Our findings demonstrate the potential of biosynthesized TiO2NPs to manage antibiotic resistance and regulate the formation of biofilms. This presents a promising direction for the creation of novel antimicrobial agents or substitutes for use in clinical settings, particularly in the management of isolates capable of resisting multiple drugs.
Assuntos
Antibacterianos , Biofilmes , Farmacorresistência Bacteriana Múltipla , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa , Titânio , Titânio/química , Titânio/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Nanopartículas/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , beta-Lactamases/genética , beta-Lactamases/metabolismo , Nanopartículas Metálicas/química , Sinergismo Farmacológico , Humanos , Difração de Raios XRESUMO
Cubic hollow-structured NiCo-LDH was synthesized using a solvothermal method. Subsequently, clay-like Ti3C2Tx MXenes were electrostatically self-assembled with NiCo layered double hydroxides (NiCo-LDH) to form composites featuring three-dimensional porous heterostructures. The composites were characterized using SEM, TEM, XRD, XPS, and FT-IR spectroscopy. Ti3C2Tx MXenes exhibit excellent electrical conductivity and hydrophilicity, providing abundant binding sites for NiCo-LDH, thereby promoting an increase in ion diffusion channels. The formation of three-dimensional porous heterostructural composites enhances charge transport, significantly improving sensor sensitivity and response speed. Consequently, the sensor demonstrates excellent electrochemical detection capability for quercetin (Qu), with a detection range of 0.1-20 µM and a detection limit of 23 nM. Additionally, it has been applied to the detection of Qu in natural plants such as onion, golden cypress, and chrysanthemum. The recovery ranged from 97.6 to 102.28%.
Assuntos
Técnicas Eletroquímicas , Hidróxidos , Limite de Detecção , Quercetina , Titânio , Quercetina/análise , Quercetina/química , Técnicas Eletroquímicas/métodos , Técnicas Eletroquímicas/instrumentação , Porosidade , Hidróxidos/química , Titânio/química , Cobalto/química , EletrodosRESUMO
BACKGROUND: Advancements in digital dentistry helped in custom-milling screw-channels in implant-supported restorations; however, the fit of these restorations is still unclear especially for contemporary computer aided designing/computer aided manufacturing (CAD/CAM) materials. This study aimed to compare the internal and marginal fit of Ultra translucent multilayered zirconia versus lithium disilicate implant-supported hybrid abutment crowns (HACs) constructed with custom-milled screw-channels on Titanium-base. MATERIALS AND METHODS: A total of 24 HACs with custom-milled screw-channels were constructed from lithium disilicate (Group LDS) and Ultra translucent multilayered zirconia (Group UT) using digital workflow (n = 12). The internal and marginal gaps of HACs on their corresponding Titanium-bases were assessed using replica technique and stereomicroscope, respectively. After testing for normality, quantitative data were expressed as mean and standard deviation and compared using independent t-test at a level of significance (P ≤ 0.05). RESULTS: There was no statistically significant difference between Group LDS and Group UT in terms of marginal and internal fit. The internal and marginal gaps in both groups were within the accepted values reported in literature. CONCLUSIONS: UT and LDS HACs with custom-milled screw-channels demonstrated comparable and acceptable internal fit and marginal adaptations to Ti-base, which lied within the range reported in literature.
Assuntos
Desenho Assistido por Computador , Coroas , Projeto do Implante Dentário-Pivô , Adaptação Marginal Dentária , Prótese Dentária Fixada por Implante , Titânio , Zircônio , Titânio/química , Zircônio/química , Humanos , Porcelana Dentária/química , Técnicas In Vitro , Dente Suporte , Cerâmica/química , Planejamento de Prótese DentáriaRESUMO
Laser texturing seems to be a promising technique for reducing bacterial adhesion on titanium implant surfaces. This work aims to demonstrate the possibility of obtaining a functionally orientated surface of titanium implant elements with a specific architecture with specific bacteriological and photocatalytic properties. Femtosecond laser-generated surface structures, such as laser-induced periodic surface structures (LIPSS, wrinkles), grooves, and spikes on titanium, have been characterised by XRD, Raman spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of the titanium surfaces produced was tested based on the degradation effect of methylene blue (MB). The correlation between the photocatalytic activity of TiO2 coatings and their morphology and structure has been analysed. Features related to the size, shape, and distribution of the roughness patterns were found to influence the adhesion of the bacterial strain on different surfaces. On the laser-structurised surface, the adhesion of Escherichia coli bacteria were reduced by 80% compared to an untreated reference surface.
Assuntos
Antibacterianos , Aderência Bacteriana , Escherichia coli , Lasers , Propriedades de Superfície , Titânio , Titânio/química , Titânio/farmacologia , Escherichia coli/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/química , Aderência Bacteriana/efeitos dos fármacos , Catálise , Microscopia Eletrônica de Varredura , Humanos , Azul de Metileno/química , Azul de Metileno/farmacologia , Peri-Implantite/microbiologiaRESUMO
Heavy mineral deposits occur in several coastal areas of the world, formed over a long period due to variations in mean sea level, wave action, and winds. These are the main sources of ilmenite (FeTiO3), which in turn is the source of more than 80% of the TiO2 produced and applied in various industries, most recently in nanotechnology. The present study mapped heavy mineral deposits on the coast of Rio Grande do Sul in southern Brazil using integrated proximal and orbital thermal infrared (TIR) remote sensing techniques. Mineral groups, such as oxides and silicates, have spectral features in the TIR wavelengths. Using laboratory spectroscopy at TIR using Nicolet 6700 Thermo Scientific Spectrometer, we measured the spectral signature of the local sample of heavy minerals (between 8 and 14 µm) and identified a diagnostic spectral feature at 10.75 µm. The signature was resampled to be compatible with the Advanced Spaceborne Thermal Emission Radiometer (ASTER) sensor bandwidth values and used as a reference endmember for the Spectral Angle Mapper (SAM) and Linear Spectral Unmixing (LSU) digital image classification algorithms. Thus, we identified the presence of the reference endmember (heavy minerals) in the pixels of the ASTER scene. In pixels classified by SAM as the presence of heavy minerals, LSU was applied to estimate the surface concentration within the pixel. The results showed a concentration of up to 20% of heavy minerals, with the highest concentration on the beach and dune fields. Opaque minerals such as ilmenite do not have spectral reflectance features in visible, near-infrared, and short-wave infrared, which makes their identification by remote sensing difficult. The present study showed that the integration of proximal and orbital as well as hyperspectral and multispectral thermal data can be considered as an alternative for detecting and mapping heavy minerals in coastal areas.
Assuntos
Minerais , Tecnologia de Sensoriamento Remoto , Brasil , Minerais/análise , Tecnologia de Sensoriamento Remoto/métodos , Monitoramento Ambiental/métodos , Titânio/análise , Titânio/químicaRESUMO
NANOTECHNOLOGY: is the art and science of dealing with nanoscale particles. This has transformed contemporary dental practices through myriad contributions to biomaterial science. Titanium dioxide nanoparticles procured from Bacillus subtilis, an eco-friendly and biogenic source, can significantly magnify the physiochemical attributes of dental materials. However, postoperative sensitivity is a major drawback of composite restorations. The incorporation of these nanoparticles into dental adhesives can greatly benefit clinical dentistry by resolving this issue. This trial aimed to evaluate the effectiveness of a novel titanium dioxide nanofortified adhesive on the postoperative sensitivity of composite restorations. METHODS: This triple-blind, parallel-group randomized controlled trial was conducted at the Department of Operative Dentistry and Endodontics, School of Dentistry, Islamabad, from May 15, 2023, to November 25, 2023. Participants (n = 60) with Class I and II primary carious lesions with a minimum cavity depth of 3-5 mm were randomly assigned to two groups (n = 30). After obtaining informed consent, the restorative procedure was accomplished using a minimally invasive approach and etch-and-rinse adhesive strategy. In group A, a nanofortified adhesive was used for composite restoration, whereas in group B, an adhesive without nanoparticles was used. Postoperative sensitivity was evaluated using the Visual Analog Scale (VAS) score at follow-up periods: of one day, one week, two weeks and one month. A Chi-square test was used to compare postoperative sensitivity between the two groups. The level of significance was set at p < 0.05. RESULTS: A noteworthy association was observed between sensitivity and the group variable at all four evaluation periods: after one day (p = 0.002), 1 week (p = 0.002), 2 weeks (p = 0.007) and one month. In conclusion, participants who underwent restorative intervention using titanium dioxide nanoreinforced adhesives reported a notable reduction in sensitivity at all time intervals. Hence, the occurrence and severity of postoperative sensitivity are significantly reduced using Bacillus subtilis-procured nanofortified adhesives as compared to conventional adhesives without nanoparticles. TRIAL REGISTRATION: This trial was retrospectively registered at ClinicalTrials.gov (ID: NCT06242184) on 03/02/2024. All procedures involving human participants were performed in conformance with this protocol.
Assuntos
Bacillus subtilis , Resinas Compostas , Cimentos Dentários , Titânio , Humanos , Bacillus subtilis/efeitos dos fármacos , Feminino , Masculino , Titânio/química , Resinas Compostas/uso terapêutico , Cimentos Dentários/uso terapêutico , Sensibilidade da Dentina/prevenção & controle , Nanopartículas , Restauração Dentária Permanente/métodos , Cárie Dentária/prevenção & controle , Adolescente , Adulto , Adulto JovemRESUMO
Nickel-titanium (NiTi) instruments offer many advantages during endodontic instrumentation; however, the fracture risk within the canal remains a concern. Manufacturers continuously develop and introduce instruments to the market with supposedly enhanced cyclic fatigue resistance and increased flexibility, achieved through different proprietary manufacturing processes, the details of which have not been made public. In recent years, two rotary systems specially designed for deciduous teeth have been commercially available, but information about their performance is lacking. This investigation aimed to identify which manufacturing process provides better cyclic fatigue resistance: the AF-H Wire technology used in the AF baby rotary files (AF-f) or the CM-Wire technology used in the i3 Gold deciduous teeth rotary files (i3G-f). Forty rotary International Organization for Standardization (ISO) 25/04 files were tested in artificial canals with a standard geometry of 60° angle and 2.5 mm radius until fracture. The number of cycles to fracture was calculated, and the length of the fragments was measured. A scanning electron microscope (SEM) was used to examine the fracture surfaces and fragments. Energy dispersive spectroscopy (EDS) was used to determine the percentage weight of NiTi in each file. The statistical analysis (Mann-Whitney test) showed that the cyclic fatigue resistance of the AF-f was significantly higher (p < 0.0001) than that of the i3G-f. Additionally, there was a significant difference (p = 0.0419) in the length of the fractured fragments. All instruments showed one or more types of manufacturing defects and presented similar NiTi percentages by weight. The manufacturing process is critical to cyclic fatigue resistance, and there seems to be responsible for the difference in cyclic fatigue resistance between these similar instruments.
Assuntos
Falha de Equipamento , Temperatura Alta , Níquel , Preparo de Canal Radicular , Titânio , Preparo de Canal Radicular/instrumentação , Níquel/química , Humanos , Titânio/química , Desenho de Equipamento , Teste de Materiais , Instrumentos Odontológicos , Microscopia Eletrônica de Varredura , Ligas Dentárias/química , Técnicas In Vitro , Análise do Estresse DentárioRESUMO
In photoelectrochemical (PEC) sensors, traditional detection modes such as "signal-on", "signal-off", and "polarity-switchable" limit target signals to a single polarity range, necessitating novel design strategies to enhance the operational scope. To overcome this limitation, we propose, for the first time, a "polarity-transcendent" design concept that enables a continuous response across the polarity spectrum, significantly broadening the sensor's concentration detection range. This concept is exemplified in our new "background-enhanced signal-off polarity-switchable" (BESOPS) mode, where the model analyte let-7a activates a cascade shearing reaction of a DNAzyme walker in conjunction with CRISPR/Cas12a, quantitatively peeling off Cu2O-H2 strands at the Cu2O/TiO2 electrode interface to expose the TiO2 surface. This exposure generates an anodic photocurrent at the expense of the cathodic photocurrent from Cu2O/TiO2, facilitating a seamless transition of the target signal from cathodic to anodic. Through systematic experiments and comparative analyses, the BESOPS sensor demonstrates highly sensitive and precise quantification of let-7a, with a detection limit of 2.5 aM and a broad operating range of 10 aM to 10 nM. Its performance exceeds most reported sensor platforms, highlighting the significant potential of our polarity-transcendent design in expanding the operational range of PEC sensors. This innovative approach paves the way for developing next-generation PEC sensors with enhanced applicability and heightened sensitivity in various critical fields.