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1.
Zhongguo Yi Liao Qi Xie Za Zhi ; 45(2): 119-124, 2021 Apr 08.
Artículo en Chino | MEDLINE | ID: mdl-33825367

RESUMEN

Effects of heat treatment conditions (including temperature and time) on the shape memory recovery and corrosion resistance of NiTi self-expanding vascular stents were studied based on working mechanism and clinical use. The Af temperature, dimensional recovery, crush resistance with radially applied load and point applied load of stents and corrosion resistance were characterized in diffident heat treatment conditions. The research results allow the conclusion that the stent treated at 500 ℃ for 10 min has optimum performance, and corrosion resistance meets the requirements.


Asunto(s)
Aleaciones , Calor , Corrosión , Ensayo de Materiales , Stents , Propiedades de Superficie , Temperatura , Titanio
2.
Huan Jing Ke Xue ; 42(3): 1166-1176, 2021 Mar 08.
Artículo en Chino | MEDLINE | ID: mdl-33742913

RESUMEN

A total of 86 soil samples, 86 corn kernel samples, 50 tailings samples, and 33 ore rock samples were collected in reclaimed land and surrounding areas of typical vanadium-titanium magnetite tailings located in the Chengde Central Region and analyzed for 14 elements (P, Fe, Cu, Ni, Cd, Cr, Pb, Zn, Hg, Ti, Mn, and Mo) and speciation of heavy metals. This study investigated the bioaccumulation and translocation characteristics of heavy metals in a soil-maize system based on a descriptive statistical analysis, a geological accumulative index, bioconcentration factors, and a redundancy analysis. The results showed that the average accumulation index of surface soil followed an order of P > Cu > Fe2O3 > Cr > Ti > V > Ni > Mn > Cd > Zn > Mo > As > Pb > Hg, while the accumulation level of heavy metals was generally categorized as either no accumulation or moderate accumulation. Compared to China's soil environmental quality standard risk screening values (GB15618-2018), the over-standard rates of Cr and Cu were 2.32% and 1.16%, respectively. The content of Fe, Ti, As, Pb, and Mn in the corn kernels of the tailings and surrounding areas was relatively high, and the content of Mo, Ni, Cu, Zn, Cd, and Cr in the control area was relatively high. The over-standard rates of Ni, Zn, and Cu in the corn kernels were 13.61%, 13.23%, and 5.17% respectively, according to China's national food safety standard limits for contaminants in food (GB 2762-2017). The bioconcentration factors of Fe, Ti, As, Pb, and Mn in the corn kernels of the tailings and the surrounding areas were relatively higher, while the bioconcentration factors of Mo, Ni, Cu, Zn, Cd, and Cr were lower than in control area. The bioactive components of Cd accounted for 50.17%, which was the highest, followed by Ni, Zn, and Cu with average ratios of 13.61%, 13.23%, and 5.17%, respectively. Compared to the control area, the Pb, As and Hg elements in the soil samples of the reclaimed land showed a lower total amount but a higher bioavailability content and soil pH value, while the Cu and Hg elements showed a higher total amount but lower bioavailability content and soil pH value. These differences in total heavy metal concentrations, bioavailability amounts, and soil pH values made the bioconcentration intensity of As and Pb in the tailings reservoir and surrounding area relatively higher. When studying the ecological risk of heavy metal pollution or determining the remediation target value of reclaimed land in a mine tailings reservoir and the soil around the mine area, the bioavailable state limit of heavy metals should be should be taken into account as the evaluation standard.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Bioacumulación , China , Monitoreo del Ambiente , Óxido Ferrosoférrico , Metales Pesados/análisis , Medición de Riesgo , Suelo , Contaminantes del Suelo/análisis , Titanio , Vanadio , Zea mays
3.
Acta Chir Orthop Traumatol Cech ; 88(1): 69-74, 2021.
Artículo en Checo | MEDLINE | ID: mdl-33764871

RESUMEN

The authors report on three cases in which a custom-made 3D printed titanium acetabular component of total hip arthroplasty was used to manage an advanced acetabular bone defect with pelvic discontinuity. The implant surface structure impeded long-term bone integration. Nonetheless, the stable bridging of the acetabular defect resulted in full integration of impacted bone allografts at the base of the implant. The pelvic continuity was restored within 12 months after surgery, and thus the acetabulum was prepared for potential further implantation of a standard revision acetabular component. Only one of the three female patients underwent a revision surgery at 18 months after surgery, the other two female patients were satisfied to such a degree with the clinical outcome at 6 years and 5 years, respectively, after surgery that they refused to undertake the revision surgery, despite X-ray images showing signs of loosening of the custom-made titanium acetabular component. The authors concluded that the implantation technique of three-point fixed custom-made 3D printed acetabular component made of titanium combined with impaction grafting of the acetabular base is a good alternative in managing the advanced bone defects of acetabulum with pelvic discontinuity after the failure of total hip arthroplasty. Even though inadequate surface porosity of the thus produced component did not allow its permanent osteointegration, the assembly was stable enough to allow the bone allografts to rebuild and restore continuity of the pelvis and facilitated future implantation of the standard revision acetabular component. Key words: 3D printing, individual acetabular component, titanium, total hip prosthesis, revision hip arthroplasty, acetabular reconstruction, custom-made implants.


Asunto(s)
Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Acetábulo/diagnóstico por imagen , Acetábulo/cirugía , Femenino , Estudios de Seguimiento , Humanos , Impresión Tridimensional , Diseño de Prótesis , Falla de Prótesis , Reoperación , Titanio , Resultado del Tratamiento
4.
Water Sci Technol ; 83(6): 1357-1368, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33767042

RESUMEN

Conventional biological treatments used in most Indonesian landfill sites are mostly ineffective in treating stabilized landfill leachates to meet the standard regulation. Thus, a combination of biological and electrochemical process is offered to successfully treat leachates containing a high concentration of organic and nitrogenous compounds. In this study, a moving bed biofilm reactor (MBBR) was applied prior to electrochemical oxidation by using boron-doped diamond (BDD), Ti/IrO2, and Ti/Pt anodes with applied current of 350, 400 and 450 mA. The objectives were to investigate the effect of anode type and the applied current on the removal of organics as well as total nitrogen from the MBBR-treated leachate with electrochemical oxidation. The optimum removal of chemical oxygen demand (COD) observed on the Ti/Pt anode was 78% by applying 400 mA, with an estimated energy of 56.7 Wh g L-1. In the case of Ti/IrO2 and BDD anodes, the optimum removal of COD was 76 and 85% with an energy consumption of 58.9 and 36.9 Wh g L-1, respectively, both achieved at 350 mA. Although all anodes showed less-satisfactory performances for total nitrogen reduction, around 46-95% removal of nitrogenous compounds was achieved by MBBR, with their partial conversion to nitrates.


Asunto(s)
Diamante , Contaminantes Químicos del Agua , Biopelículas , Reactores Biológicos , Boro , Electrodos , Indonesia , Oxidación-Reducción , Titanio , Contaminantes Químicos del Agua/análisis
5.
Zhongguo Gu Shang ; 34(3): 237-42, 2021 Mar 25.
Artículo en Chino | MEDLINE | ID: mdl-33787168

RESUMEN

OBJECTIVE: To compare the clinical efficacy of titanium cable biomimetic reconstruction of coracoclavicular ligament and clavicular hook plate in the treatment of acromioclavicular joint dislocation. METHODS: The clinical data of 39 patients with severe acute acromioclavicular joint dislocation from January 2017 to December 2018 were retrospectively analyzed, 19 patients in double strand titanium cable group, including 13 males and 6 females, aged from 26 to 67 years old; Rockwood classification:10 cases of type Ⅲ, 4 cases of type Ⅳ and 5 cases of type Ⅴ;8 cases of traffic injury and 11 cases of fall injury;the time from injury to operation was 3 to 6 days. There were 20 patients in steel plate group, including 15 males and 5 females, aged from 25 to 71 years old. Rockwood classification:11 cases of type Ⅲ, 4 cases of typeⅣ, 5 cases of type Ⅴ;7 cases of traffic injury, 13 cases of fall injury;the time from injury to operation was 2 to 7 days. The length of incision, operation time, intraoperative blood loss, cost, VAS score before and after operation, and Constant-Murley score before and after operation were compared between two groups. Postoperative X-ray films were taken to observe the reduction and maintenance of acromioclavicular joint dislocation. Complications were recorded. RESULTS: Thirty-six patients were followed up for 12 to 14 months. The amount of intraoperative blood loss in the two groups was basically the same. The operation incision in double strand titanium cable group was shorter, the operation time in steel plate group was shorter, and the operation cost in double strand titanium cable group was less. One week and one year after operation, the pain of double strand titanium cable group was less than that of steel plate group. One year after operation, the Constant-Murley score of double strand titanium cable group was higher than that of steel plate group. The postoperative X-ray showed that the acromioclavicular joint in double strand titanium cable group was well reduced, and there was 1 case with slight reduction loss. In the plate group, there was no reduction loss after removal of the clavicular hook plate, and 8 patients had distal clavicular bone atrophy or acromion bone resorption. In steel plate group, 4 cases had long-term postoperative pain, postoperative dysfunction and other complications. CONCLUSION: The clinical effect of coracoclavicular ligament reconstruction with double strand titanium cable is better than that of clavicular hook plate in the treatment of severe acute acromioclavicular joint dislocation, with less trauma (no secondary operation) and lower cost.


Asunto(s)
Articulación Acromioclavicular , Luxaciones Articulares , Articulación Acromioclavicular/cirugía , Adulto , Anciano , Placas Óseas , Femenino , Humanos , Luxaciones Articulares/cirugía , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Titanio , Resultado del Tratamiento
6.
Prog Orthod ; 22(1): 9, 2021 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-33748887

RESUMEN

BACKGROUND: The mechanical strength of mini-implants is a critical factor due to their small diameters. Currently, it is not possible to state whether there is a relevant difference between the mechanical properties of stainless steel (SS-MIs) and titanium alloy mini-implants (TA-MIs). The objective of this study was to test the null hypothesis that there is no difference in the mechanical strength of SS-MIs and TA-MIs, and to analyze, by scanning electron microscopy (SEM), the SS-MI, and TA-MI threads resistance to morphological damage after insertion. METHODS: A standardized sample of 504 SS-MIs and TA-MIs with diameters ranging from 1.2 mm to 1.8 mm was used. Torsional fracture was performed in 154 MIs. Flexural strength of 280 MIs was evaluated at 1 mm and 2 mm-deflection. The threads of 70 MIs were morphologically analyzed by scanning electron microscopy (SEM), before and after their insertion in high-density artificial bone blocks. Comparisons between SS-MIs and TA-MIs were performed with t tests or Mann-Whitney U tests. A multiple linear regression analysis was used to evaluate the influence of variables on the ranging of MI mechanical strength. RESULTS: SS-MIs had higher fracture torque. The mean difference between the SS-MIs and TA-MIs fracture torque was of 4.09 Ncm. The MI diameter explained 90.3% of the total variation in fracture torque, while only 2.2% was explained by the metallic alloy. The SS-MI group presented a higher deformation force during the 1mm and 2mm-deflection. The mean difference between the flexural strength of SS and TA-MIs at 1 mm and 2 mm-deflection was of 18.21 N and 17.55 N, respectively. There was no noticeable morphological damage to the threads of SS-MIs and TA-MIs. CONCLUSIONS: The null hypothesis was rejected. SS-MIs were 13.2% and 20.2% more resistant to torsional fracture and deflection, respectively. The threads of the SS-MIs and TA-MIs were not damaged during the insertion and removal process. Thus, the use of SS-MI can reduce the fracture risk without increasing the MI diameter.


Asunto(s)
Métodos de Anclaje en Ortodoncia , Acero Inoxidable , Aleaciones , Humanos , Laboratorios , Ensayo de Materiales , Diseño de Aparato Ortodóncico , Estrés Mecánico , Titanio , Torque
7.
J Environ Manage ; 286: 112130, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33684804

RESUMEN

Silver nanoparticles doped with FCNT-TiO2 heterogeneous catalyst was prepared via one-step chemical reduction process and their efficacy was tested for hydrogen production under solar simulator. Crystallinity, purity, optical properties, and morphologies of the catalysts were examined by X-Ray diffraction, Raman spectroscopy, UV-Visible diffuse reflectance spectra, and Transmission Electron Microscopy. The chemical states and interface interactions were studied by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The optimized catalyst showed 19.2 mmol g-1 h-1 of hydrogen production, which is 28.5 and 7 times higher than the pristine TiO2 nanoparticles and FCNT-TiO2 nanocomposite, respectively. The optimized catalyst showed stability up to 50 h under the solar simulator irradiation. The natural solar light irradiated catalyst showed ~2.2 times higher hydrogen production rate than the solar simulator irradiation. A plausible reaction mechanism of Ag NPs/FCNT-TiO2 photocatalyst was elucidated by investigating the beneficial co-catalytic role of Ag NPs and FCNTs for enhanced hydrogen production.


Asunto(s)
Nanopartículas del Metal , Plata , Catálisis , Hidrógeno , Luz , Titanio
8.
Int J Nanomedicine ; 16: 1889-1899, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33707944

RESUMEN

Introduction: Sonodynamic therapy (SDT) has good targeting and non-invasive advantages in the treatment of solid cancers, and checkpoint blockade immunotherapy is also a promising treatment to cure cancer. However, their antitumor effects are not sufficient due to some inherent factors. Some studies that combined SDT with immunotherapy or nanoparticles have managed to enhance its efficiency to treat cancers. Methods: In this work, an effective therapeutic strategy that can potentiate the antitumor efficacy of anti-PD-L1 antibody (aPD-L1) is developed by the use of cascade immuno-sonodynamic therapy (immuno-SDT). Titanium dioxide (TiO2), a nanostructured agent for SDT, sonosensitizer Chlorin e6 (Ce6), and immunological adjuvant CpG oligonucleotide (CpG ODN), are used to construct a multifunctional nanosonosensitizer (TiO2-Ce6-CpG). Then, we conducted in vitro and in vivo experiments to explore the antitumor effect of TiO2-Ce6-CpG under ultrasound (US) treatment. Results: The characterization tests showed that the nanosonosensitizers are polycrystalline structure with homogeneous sizes, resulting in a good drug loading efficiency. The innovative nanosonosensitizers (TiO2-Ce6-CpG) can not only effectively inhibit tumor growth but also stimulate the immune system to activate the adaptive immune responses, using the TiO2-Ce6 to augment SDT and the immune adjuvant CpG to enhance the immune response. After combined with the aPD-L1, the synergistic effect could not only efficiently inhibit the primary tumor growth but also lead to an inhibition of the non-irradiated pre-existing distant tumors by inducing a strong tumor-specific immune response. Conclusion: In this study, we present an effective strategy for tumor treatment by combining nanosonosensitizer-augmented SDT and aPD-L1 checkpoint blockade. This work provides a promising strategy and offers a new vision for treating malignant tumors.


Asunto(s)
/uso terapéutico , Inmunoterapia , Nanopartículas/química , Neoplasias/inmunología , Neoplasias/terapia , Terapia por Ultrasonido , Animales , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Terapia Combinada , Células Dendríticas/efectos de los fármacos , Endocitosis/efectos de los fármacos , Femenino , Humanos , Inmunidad/efectos de los fármacos , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Nanopartículas/ultraestructura , Neoplasias/patología , Oligodesoxirribonucleótidos/química , Porfirinas/química , Especies Reactivas de Oxígeno/metabolismo , Titanio/química
9.
Aquat Toxicol ; 233: 105790, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33662879

RESUMEN

The potential exposure of titanate nanotubes (TNTs) to wildlife and humans may occur as a result of increased use and application as functional nanomaterials. However, there is a dearth of knowledge regarding the pathways of uptake and excretion of TNTs and their toxicity in cells. In this study, three strains of the Tetrahymena genus of free-living ciliates, including a wild type strain (SB210) and two mutant strains (SB255: mucocyst-deficient; NP1: temperature-sensitive "mouthless''), were used to study the pathways of uptake and excretion and evaluate the cytotoxicity of TNTs. The three Tetrahymena strains were separately exposed to 0, 0.01, 0.1, 1 or 10 mg/L of TNTs, and cells were collected at different time points for quantification of intracellular TNTs (e.g., 5, 10, 20, 40, 60, 90 and 120 min) and evaluation of cytotoxicity (12 and 24 h). TNT contents in NP1 and SB255 were greater or comparable to the contents in SB210 while exposure to 10 mg/L TNTs in 120 min. Furthermore, exposure to 10 mg/L TNTs for 24 h caused greater decreases in cell density of NP1 (38.2 %) and SB255 (36.8 %) compared with SB210 (26.5 %) and upregulated the expression of caspase 15 in SB210. Taken together, our results suggested that TNT uptake by pinocytosis and excretion by exocytosis in Tetrahymena, and the exposure could cause cytotoxicity which can offer novel insights into the accumulation kinetics of nanotubes and even nanomaterials in single cell.


Asunto(s)
Nanotubos/toxicidad , Organismos Modificados Genéticamente/efectos de los fármacos , Tetrahymena/efectos de los fármacos , Titanio/toxicidad , Contaminantes Químicos del Agua/toxicidad , Transporte Biológico , Colorantes , Relación Dosis-Respuesta a Droga , Exocitosis/efectos de los fármacos , Humanos , Cinética , Organismos Modificados Genéticamente/metabolismo , Pinocitosis/efectos de los fármacos , Tetrahymena/genética , Tetrahymena/metabolismo , Titanio/metabolismo , Contaminantes Químicos del Agua/metabolismo
10.
Bone Joint J ; 103-B(3): 522-529, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33641411

RESUMEN

AIMS: The aim of this study was to develop a single-layer hybrid organic-inorganic sol-gel coating that is capable of a controlled antibiotic release for cementless hydroxyapatite (HA)-coated titanium orthopaedic prostheses. METHODS: Coatings containing gentamicin at a concentration of 1.25% weight/volume (wt/vol), similar to that found in commercially available antibiotic-loaded bone cement, were prepared and tested in the laboratory for: kinetics of antibiotic release; activity against planktonic and biofilm bacterial cultures; biocompatibility with cultured mammalian cells; and physical bonding to the material (n = 3 in all tests). The sol-gel coatings and controls were then tested in vivo in a small animal healing model (four materials tested; n = 6 per material), and applied to the surface of commercially pure HA-coated titanium rods. RESULTS: The coating released gentamicin at > 10 × minimum inhibitory concentration (MIC) for sensitive staphylococcal strains within one hour thereby potentially giving effective prophylaxis for arthroplasty surgery, and showed > 99% elution of the antibiotic within the coating after 48 hours. There was total eradication of both planktonic bacteria and established bacterial biofilms of a panel of clinically relevant staphylococci. Mesenchymal stem cells adhered to the coated surfaces and differentiated towards osteoblasts, depositing calcium and expressing the bone marker protein, osteopontin. In the in vivo small animal bone healing model, the antibiotic sol-gel coated titanium (Ti)/HA rod led to osseointegration equivalent to that of the conventional HA-coated surface. CONCLUSION: In this study we report a new sol-gel technology that can release gentamicin from a bioceramic-coated cementless arthroplasty material. In vitro, local gentamicin levels are in excess of what can be achieved by antibiotic-loaded bone cement. In vivo, bone healing in an animal model is not impaired. This, thus, represents a biomaterial modification that may have the potential to protect at-risk patients from implant-related deep infection. Cite this article: Bone Joint J 2021;103-B(3):522-529.


Asunto(s)
Materiales Biocompatibles Revestidos/farmacología , Durapatita/farmacología , Gentamicinas/farmacología , Infecciones Relacionadas con Prótesis/microbiología , Infecciones Relacionadas con Prótesis/prevención & control , Infecciones Estafilocócicas/prevención & control , Titanio/farmacología , Animales , Biopelículas/efectos de los fármacos , Ensayo de Materiales , Ratas
11.
Water Sci Technol ; 83(5): 1072-1084, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33724937

RESUMEN

A novel TiO2 nanoparticle was prepared through green synthesis using Calotropis gigantea (CG) leaf extract. Morphological analysis showed dispersed spherical CG-TiO2 nanoparticles with an average size of 42 nm. The prepared catalyst was used for the degradation of metformin (a widely used diabetic medicine) by solar photocatalysis. A three-factor central composite design (CCD) was used to explore the effect of independent variables, i.e., pH 3-7, metformin concentration 1-10 mg/L, and catalyst (CG-TiO2) dosage 0.5-2.0 g/L. A maximum metformin degradation of 96.7% was observed under optimum conditions i.e., pH = 9.7, initial metformin concentration = 9.7 mg/L and catalyst dosage = 0.7 g/L, with ∼86% mineralization efficiency. A quadratic model with an error <±5% was developed to predict the metformin degradation and the rate of degradation under the optimum conditions followed pseudo-first-order kinetics (k = 0.014/min). CG-TiO2 exhibited higher metformin degradation efficiency (96.7%) compared to P-25 (23.9%) at optimum conditions. The recyclability study indicated effective reuse of the catalyst for up to three cycles. The proposed metformin degradation route is hydroxyl radical (•OH) generation on the CG-TiO2 surface, transfer of •OH to the aqueous phase from CG-TiO2 and subsequent oxidation of metformin in the aqueous phase.


Asunto(s)
Calotropis , Metformina , Catálisis , Extractos Vegetales , Titanio
12.
Water Sci Technol ; 83(5): 1242-1249, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33724950

RESUMEN

Recently, the utilization of wastes, recovery of high value-added products from waste, and their use as raw materials in other industries with the logic of industrial symbiosis has become an important issue. In this study, removal efficiency of Reactive Orange 16 (RO16) dye from aqueous solution was studied using TiO2 catalyst recycled from an industrial waste effluent. The recycling of TiO2 waste from a paints manufacturing industry was carried out by sintering the TiO2-containing waste. The catalyst usability of TiO2-containing powder was then investigated in the removal of RO16 dye by photocatalytic oxidation process. In photocatalytic oxidation studies, TiO2/UV and TiO2/UV/H2O2 processes were investigated, where the effect of annealing temperature, the effect of H2O2 concentration, and the adsorption and photocatalytic effects on RO16 dye removal were studied. The results showed that 100% RO16 removal was obtained for the 10 mg/L initial RO16 concentration using the TiO2 (1 g/L)/UV process. At high initial RO16 concentration (50 mg/L), 100% RO16 removal was achieved by adding 10 mM H2O2.


Asunto(s)
Peróxido de Hidrógeno , Purificación del Agua , Catálisis , Titanio , Aguas Residuales
13.
Chemosphere ; 271: 129847, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33736219

RESUMEN

P25 TiO2 photoanodes are used to photo-oxidise water in two different acids, 0.5 M H2SO4 and 1 M HClO4. In the former acid, the linear sweep voltammogram, LSV, appears to exhibit two photocurrent waves, whilst only one in the latter. In 0.5 M H2SO4, the recorded LSV coupled with a low faradaic efficiency (0.58) for the photooxidation of water to O2, fO2, and a significant level of persulfate, fS2O8 = 0.12, shows that the electrochemical kinetics are not simply those for water oxidation. In 1 M HClO4, the LSV coupled with a high fO2 value (0.91) suggest that the photocurrent is due to water oxidation. Photo-induced absorption spectroscopy, PIAS, measurements made using the P25 TiO2 photoanode reveal a steady state absorbance change, ΔAbsss, associated with the steady-state concentration of surface accumulated holes, [h+]ss, which varies with: (i) monitoring wavelength, with a peak at ca. 500 nm, and (ii) applied potential, flattening off at ca. 0.7 V vs Ag/AgCl. PIAS measurements, coupled with concomitant transient photocurrent (TC) measurements, on the P25 TiO2 photoanode polarised at 1.3 v vs Ag/AgCl, in 1 M HClO4, show that the oxidation of water is second order with respect the concentration of the surface-accumulated, photogenerated holes, [h+]ss, which have a calculated turnover frequency of 19 s-1, under 1 sun irradiation. This is the first reported example of the use of PIAS/TC to probe the photoelectrochemical kinetics exhibited by a mesoporous semiconductor photoanode derived from a powder, for water oxidation and the significance of such is discussed briefly.


Asunto(s)
Titanio , Agua , Cinética , Oxidación-Reducción
14.
Sci Total Environ ; 770: 145340, 2021 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-33736383

RESUMEN

MAX phase materials are a new type of nanomaterial with wide applications, but the potential effects of MAX phase materials on plants have not been reported. Herein, we selected Ti3AlC2 nanosheets as a typical MAX phase material to investigate its potential impacts on rice (Oryza sativa L.) at 0-1000 µg·mL-1. The foliar application of Ti3AlC2 at 100 and 1000 µg·mL-1 inhibited the growth of rice seedlings by producing excess reactive oxygen species (ROS). Furthermore, foliar spraying of Ti3AlC2 at 100 µg·mL-1 decreased the stomatal aperture (78.6%) and increased the number of trichomes (100%). These responses demonstrated that the application of Ti3AlC2 could interfere with the immune system of plants by changing the structure and function of leaves, disturbing the activities of antioxidant enzymes. According to the above results, we concluded that the toxicity of Ti3AlC2 nanosheets on plants was mainly caused by the release of titanium ions. This study provides a valuable reference for understanding the impact of MAX phase materials on plants.


Asunto(s)
Oryza , Antioxidantes , Estrés Oxidativo , Plantones , Titanio/toxicidad
15.
J Biomed Nanotechnol ; 17(1): 37-52, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33653495

RESUMEN

Nanoparticulate titanium dioxide (nano-TiO2) is a commonly used nanoparticle material and has been widely used in the fields of medicine, cosmetics, construction, and environmental protection. Numerous studies have demonstrated that nano-TiO2 has toxic effects on neuronal development, which lead to defects in learning and memory functions. However, it is still unclear whether nano-TiO2 inhibits the development of synapse and the underlying molecular mechanism is still unknown. In this study, nano-TiO2 was administered to rat primary hippocampal neurons for 24 h to investigate the underlying molecular mechanisms behind the inhibition of neuronal synaptic development by nano-TiO2. We used hippocampal neurons as a model to study the effect of nano-TiO2 on synaptic development. Our results demonstrated that dendritic development that represented synaptic plasticity in hippocampal neurons was significantly inhibited in a concentration-dependent manner after exposure to nano-TiO2 for 24 h. Experiments with varying concentrations of nano-TiO2 (5, 15, and 30 g/mL) indicated that the apoptotic rate of hippocampal neurons increased, development of neuronal synapses were inhibited, and synaptic densities decreased by 24.29%, 54.29%, and 72.86%, respectively, in post-treatment with nano-TiO2. Furthermore, the results indicated that the expressions of Synapsin I (SYN I) and postsynaptic density 95 (PSD95) in neuron synapse were also significantly inhibited, particularly SYN I decreased by 18.43%, 37.2%, and 51.6%, and PSD95 decreased by 16.02%, 24.06%, and 38.74% after treatment with varying concentrations of nano-TiO2, respectively. In addition, experiments to assess the BDNF-TrkB signaling pathway indicated that nano-TiO2 inhibited the expressions of key proteins in the downstream MEK/ERK and PI3K/Akt signaling pathways by inhibiting the expression of BDNF. With concentrations of nano-TiO2 at 5, 15, and 30 µg/mL, the expression of BDNF decreased by 22.64%, 33.3%, and 53.58% compared with the control group. Further, the expression ratios of downstream key proteins p-CREB/CREB decreased by 3.03%, 18.11%, and 30.57%; p-ERK1/2/ERK1/2 ratios decreased by 19.11%, 28.82%, and 58.09%, and p-Akt1/Akt1 ratios decreased by 1.92%, 27.79%, and 41.33%, respectively. These results demonstrated that nano-TiO2 inhibited the normal function of the BDNF-TrkB signaling pathway, which is closely related to neuronal synapse. Thus, it can be hypothesized that the inhibition of neuronal synaptic growth by nano-TiO2 may be related to the inhibition of BDNF-TrkB signaling pathway.


Asunto(s)
Factor Neurotrófico Derivado del Encéfalo , Fosfatidilinositol 3-Quinasas , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Hipocampo/metabolismo , Proteínas Tirosina Quinasas , Ratas , Proteínas Tirosina Quinasas Receptoras , Transducción de Señal , Sinapsis/metabolismo , Titanio
16.
J Biomed Nanotechnol ; 17(1): 115-130, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33653501

RESUMEN

The main goal of this research is to scrutinize the effect of texture and grain size on the biological response of hierarchical structured pure titanium (Ti), examining the interrelation between grain refinement mechanisms with texture variation. The hierarchical structure was produced using two methods of severe plastic deformation (SPD). The Ti specimens were first processed up to six passes by equal channel angular pressing (ECAP) and subsequently treated at the top surface using surface mechanical attrition treatment (SMAT). Microstructure examination by Electron backscatter diffraction (EBSD) indicates that the SMAT-treated surface was categorized into three distinct microstructural regions based on the type of grain refinement process involved during SPD: twin induced dynamic recrystallization (TDRX) and geometric dynamic recrystallization (GDRX) in the topmost surface, and continuous (CDRX) and discontinuous dynamic recrystallization (DDRX) in the lower regions of the sample. The biological experiments showed meaningful improvement in the cellular response of SMATed and ECAPed samples. It was demonstrated that grain refinement could have the capability of improving the biological response of Ti surface. In this regard, SMATed + 2ECAPed sample showed the best result although it has not the smallest grain size and the highest texture intensity. It was observed that texture and grain orientation of planes have an important impact on the biological response of pure Ti and dominance of prismatic (1010) texture can improve the cell viability, adhesion and its differentiation. Therefore, microstructure and texture tailoring through combined SPD methods could be a promising strategy for the improvement of the next generation of medical implants.


Asunto(s)
Prótesis e Implantes , Titanio , Supervivencia Celular , Ensayo de Materiales , Osteoblastos
17.
Zhongguo Gu Shang ; 34(1): 73-80, 2021 Jan 25.
Artículo en Chino | MEDLINE | ID: mdl-33666024

RESUMEN

OBJECTIVE: To compare the clinical effects of three different methods of binding multi-fold rib graft, iliac bone graft and titanium mesh graft in tuberculosis of thoracic vertebra by approach of transverse rib process. METHODS: A hundred and seven patients with tuberculosis of thoracic vertebra received surgical treatment from January 2010 to December 2016 were retrospectively analyzed. The patients were divided into three groups according different methods of bone graft. The surgical approach of the transverse rib process was used in all 107 patients, after thoroughly remove the necrotic tissue of tuberculosis, three different bone grafts were used respectively including iliac bone graft (36 cases, group A), binding multi-fold rib graft (35 cases, group B), titanium mesh bone graft (36 cases, group C). Perioperative indexes, the time required for bone graft during operation, intraoperation blood loss, the loss rate of the anterior edge of the lesion, Cobb angle, postoperative bone graft fusion time, spinal nerve recovery and Oswestry Disability Index were compared among three groups. RESULTS: All the patients were followed up for 13 to 24 months, and the operation time required for bone graft was (23.2±4.1) min in group A, (23.8± 4.4)min in group B, and (25.5±4.2) min in group C, with no statistically significant difference among three groups (P>0.05). Intraoperative blood loss was (541.6±35.3) ml in group A, (546.8±27.8) ml in group B, and (540.1±34.5) ml in group C, withno statistically significant difference among three groups(P>0.05). Preoperative anterior vertebral height loss rate was (46.0± 3.1)% in group A, (46.4±3.3)% in group B, and (45.3±3.6)% in group B;at the final follow up, the loss rate of anterior vertebral height among three groups was (8.6±5.0)%, (8.1±4.2)%, (9.4±4.3)%, respectively. There were no statistically significant differences before operation and final follow-up among three groups (P>0.05). Preoperative Cobb angle was (35.1±4.8)° in group A, (35.2±4.5)° in group B and (35.2±4.5)° in group C, with no statistically significant difference among three groups (P>0.05);postoperative at 3 days, Cobb angle in three groups was (15.1±3.6)°, (15.3±3.1)° and (15.2±3.4)°, respectively, there was no statistically significant difference among three groups (P>0.05);at the final follow-up, the Cobb angle among three groups was (17.7±3.3)°, (17.9±3.9)°, (18.6±3.6)°, respectively, with no statistically significant difference among three groups (P>0.05). The time of bone graft fusion was (5.6±0.5) months in group A, (5.6±0.6) months in group B and (5.8±0.6)months in group C, with no statistically significant difference among three groups (P>0.05). Frankel classification at the final follow up, 4 cases were grade B, 7 cases were grade C, 10 cases were grade D, and 86 cases were grade E. Spinal nerve function in all three groups recovered to a certain extent after treatment, with no statistically significant difference among three groups (P> 0.05). Oswestry Disability Index at the final follow-up showed no statistically significant difference among three groups (P> 0.05). CONCLUSION: The approach of transverse rib process for debridement of lesions can effectively treat tuberculosis of thoracic vertebra by binding multi-fold rib graft, iliac bone graft and titanium mesh graft, but binding multi-fold rib graft can effectively avoid iliac bone donor complications, and is an effective alternative to iliac bone graft, which is worth popularizing.


Asunto(s)
Fusión Vertebral , Tuberculosis de la Columna Vertebral , Trasplante Óseo , Humanos , Vértebras Lumbares , Estudios Retrospectivos , Costillas/cirugía , Mallas Quirúrgicas , Vértebras Torácicas/cirugía , Titanio , Resultado del Tratamiento , Tuberculosis de la Columna Vertebral/cirugía
18.
Int J Food Microbiol ; 344: 109116, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33676332

RESUMEN

Staphylococcus aureus is among the most common zoonotic pathogens originating from animals consumed as food, especially raw chicken meat (RCM). As far as we know, this might be the first report that explores the efficacy of metal oxide nanoparticles (MONPs), such as zinc peroxide nanoparticles (ZnO2-NPs), zinc oxide nanoparticles (ZnO-NPs), and titanium dioxide nanoparticles (TiO2-NPs) against multidrug resistant (MDR) and/or pandrug resistant (PDR) S. aureus strains with a strong biofilm-producing ability isolated from RCM and giblets. The overall prevalence of coagulase-positive staphylococci was 21%, with a contamination level range between 102 and 104 CFU/g. The incidence of virulence genes See (21/36), pvl (16/36), clfA (15/36), sec (12/36), tst (12/36), and sea (11/36) among S. aureus strains were relatively higher those of seb, sed, fnbA, and fnbB. For antimicrobial resistance gene distribution, most strains harbored the blaZ gene (25/36), aacA-aphD gene (24/36), mecA gene (22/36), vanA gene (20/36), and apmA gene (20/36) confirmed the prevalence of MDR among S. aureus of RCM products. However, cfr (11/36), spc (9/36), and aadE (7/36) showed a relatively lower existence. The data of antibiogram resistance profiles was noticeably heterogeneous (25 patterns) with 32 MDR and four PDR S. aureus strains. All tested strains had a very high MAR index value (>0.2) except the P11 pattern (GEN, MXF, PMB), which showed a MAR index of 0.19. Among the strong biofilm-producing ability (BPA), 14 (70%) strains were isolated from wet markets, while only six strong BPA strains were isolated from supermarkets. The mean values of BPA ranged from 2.613 ± 0.04 to 11.013 ± 0.05. Clearly, ZnO2-NPs show significant inhibitory activity against S. aureus strains compared with those produced by the action of ZnO-NPs and TiO2-NPs. The results of anti-inflammatory activity suggest ZnO2-NPs as a lead compound for designing an alternative antimicrobial agent against drug-resistant and strong biofilm-producing S. aureus isolates from retail RCM and giblets.


Asunto(s)
Antibacterianos/farmacología , Contaminación de Alimentos/prevención & control , Staphylococcus aureus/crecimiento & desarrollo , Titanio/farmacología , Óxido de Zinc/farmacología , Animales , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Pollos/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Carne/microbiología , Nanopartículas del Metal , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/prevención & control , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Virulencia/genética
19.
Int J Nanomedicine ; 16: 1509-1523, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33658781

RESUMEN

Purpose: The study was intended to create a uniform zirconia layer even on the surface of complex structures via atomic layer deposition (ALD). The impact of crystalline zirconia deposited by ALD on bacterial adhesion and osteoblast viability was assessed via surface treatment of dental implants. Methods: Amorphous zirconia was deposited using an atomic layer deposition reactor (Atomic Classic, CN1, Hwaseong, Korea) on titanium discs. Heating the samples at 400°C resulted in crystallization. Samples were divided into three groups: the control group, the group carrying amorphous ALD-zirconia (Z group), and the heat-treated group following zirconia ALD deposition (ZH group).The surface of each sample was analyzed, followed by the assessment of adhesion of Streptococcus mutans and Porphyromonas gingivalis, and viability and differentiation of MC3T3-E1 cells. Results: The adhesion of S. mutans and P. gingivalis was significantly reduced in the Z and ZH groups compared with the control group (P < 0.05). The viability of MC3T3-E1 cells was significantly increased in the ZH group compared with the control group (P < 0.001), while no significant differences were observed in the Z group (P > 0.05). Differentiation of MC3T3-E1 cells showed a marginally significant increase in the ZH group compared with the control group (P < 0.1), while no significant differences were found in the Z group (P > 0.1). Conclusion: Compared with the pure titanium group, the groups that were coated with zirconia via ALD showed a decreased adhesion of S. mutans during the early stages of biofilm formation and P. gingivalis adhesion inducing peri-implantitis, and an increase in MC3T3-E1 cell viability and differentiation. The findings indicate the possibility of treating the implant surface to reduce peri-implantitis and improve osseointegration.


Asunto(s)
Adhesión Bacteriana , Osteoblastos/citología , Titanio/farmacología , Circonio/química , Animales , Adhesión Bacteriana/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Humanos , Ratones , Microscopía de Fuerza Atómica , Osteoblastos/efectos de los fármacos , Osteoblastos/metabolismo , Osteoblastos/ultraestructura , Espectroscopía de Fotoelectrones , Espectrometría por Rayos X , Propiedades de Superficie , Difracción de Rayos X
20.
Molecules ; 26(4)2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33670175

RESUMEN

A range of solution-processed organic and hybrid organic-inorganic solar cells, such as dye-sensitized and bulk heterojunction organic solar cells have been intensely developed recently. TiO2 is widely employed as electron transporting material in nanostructured TiO2 perovskite-sensitized solar cells and semiconductor in dye-sensitized solar cells. Understanding the optical and electronic mechanisms that govern charge separation, transport and recombination in these devices will enhance their current conversion efficiencies under illumination to sunlight. In this work, density functional theory with Perdew-Burke Ernzerhof (PBE) functional approach was used to explore the optical and electronic properties of three modeled TiO2 brookite clusters, (TiO2)n=5,8,68. The simulated optical absorption spectra for (TiO2)5 and (TiO2)8 clusters show excitation around 200-400 nm, with (TiO2)8 cluster showing higher absorbance than the corresponding (TiO2)5 cluster. The density of states and the projected density of states of the clusters were computed using Grid-base Projector Augmented Wave (GPAW) and PBE exchange correlation functional in a bid to further understand their electronic structure. The density of states spectra reveal surface valence and conduction bands separated by a band gap of 1.10, 2.31, and 1.37 eV for (TiO2)5, (TiO2)8, and (TiO2)68 clusters, respectively. Adsorption of croconate dyes onto the cluster shifted the absorption peaks to higher wavelengths.


Asunto(s)
Teoría Funcional de la Densidad , Nanoestructuras/química , Energía Solar , Titanio/química , Adsorción , Compuestos de Calcio/química , Suministros de Energía Eléctrica , Electrónica , Electrones , Óptica y Fotónica/tendencias , Óxidos/química , Luz Solar
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