Post-traumatic osteoarthritis (PTOA) develops after joint injury. Specifically, patients with anterior cruciate ligament (ACL) injury have a high risk of developing PTOA. In this review, we outline ...the incidence of ACL injury that progresses to PTOA, analyze the role of ACL reconstruction in preventing PTOA, suggest possible mechanisms thought to be responsible for PTOA, evaluate current diagnostic methods for detecting early OA, and discuss potential interventions to combat PTOA. We also identify important directions for future research. Although much work has been done, the incidence of PTOA among patients with a history of ACL injury remains high due to the complexity of ACL injury progression to PTOA, the lack of sensitive and easily accessible diagnostic methods to detect OA development, and the limitations of current treatments. A number of factors are thought to be involved in the underlying mechanism, including structural factors, biological factors, mechanical factors, and neuromuscular factor. Since there is a clear "start point" for PTOA, early detection and intervention is of great importance. Currently, imaging modalities and specific biomarkers allow early detection of PTOA. However, none of them is both sensitive and easily accessible. After ACL injury, many patients undergo surgical reconstruction of ACL to restore joint stability and prevent excessive loading. However, convincing evidence is still lacking for the superiority of ACL-R to conservative management in term of the incidence of PTOA. As for non-surgical treatment such as anti-cytokine and chemokine interventions, most of them are investigated in animal studies and have not been applied to humans. A complete understanding of mechanisms to stratify the patients into different subgroups on the basis of risk factors is critical. And the improvement of standardized and quantitative assessment techniques is necessary to guide intervention. Moreover, treatments targeted toward different pathogenic pathways may be crucial to the management of PTOA in the future.
Graphene oxide (GO) is a type of two-dimensional nanomaterial with a single-atom thickness. GO sheets contain pristine regions, oxidized regions, and a small fraction of holes. By stacking GO sheets ...together, a GO membrane can be fabricated with sufficient mechanical strength. The interlayer nanocapillary network formed from connected interlayer spaces, together with the gaps between the edges of noninterlocked neighboring GO sheets and cracks or holes of the GO sheet, provides passage for molecules or ions to permeate through the GO membrane in an aqueous solution. The characteristics of molecules or ions (e.g., their size, charge, and the interaction with the GO membrane) affect the separation performance of the GO membrane. The contribution of gaps between neighboring GO sheets for separation can be adjusted by changing the GO sheet size and the GO membrane thickness. The interlayer space of the GO membrane can be adjusted by changing the water pH and modifying or reducing the GO sheets to obtain the desired separation performance. The production of the GO membrane is easily scalable and relatively inexpensive, indicating that the GO membrane has promising potential for applications such as water treatment, desalination, anticorrosion, chemical resistance, and controlled release coatings.
The electrosorption performances of different ions in a capacitive deionization process were studied. The hydration ratio, i.e., the ratio of hydrated radius to ion radius, significantly affects the ...electrosorption capacity and selectivity. In a mono-ionic solution, ions with low hydration ratios exhibit high electrosorption capacities. The electrosorption capacity demonstrates a negative linear relationship with the hydration ratio for both anions and cations. In a multi-ionic solution, the monovalent ions with low hydration ratios exhibited high electrosorption selectivity. Divalent ions adsorb more easily onto electrode surface than monovalent ions do, resulting in higher electrosorption selectivity. In the late period of the electrosorption, the adsorbed ions were partly substituted by ions with lower hydration ratios or a higher valence. The hydration ratio and valence affect the ions' electrostatic attraction to the electrodes, determining the electrosorption capacity and selectivity of ions in capacitive deionization.
The hydration ratio, i.e., the ratio of hydrated radius to ion radius, significantly affects the electrosorption capacity and selectivity. Monovalent ions with a low hydration ratio exhibit high adsorption capacity and selectivity. The adsorbed ion is easily substituted by ions with lower hydration ratios or a higher valence. Display omitted
•Electrosorption selectivity in a competitive multi-ionic solution was studied.•Monovalent ions with a low hydration ratio exhibit high selectivity.•Divalent ions demonstrate higher selectivity than monovalent ions.•The adsorbed ion is easily substituted by ions with lower hydration ratios.
An efficient process for nano-silica particle modification, comprising aqueous mixing, spray drying and thermal treatment, was developed reaching a high grafting density of 13.48APTESnm−2. After the ...successive stages, APTES conversions were 25.3%, 50.7% and 80.6%. The reaction of APTES on the surface was reversible in the thermal treatment.
•Developed a novel and efficient process for nano-silica particle modification.•The stages of aqueous mixing, spray drying and thermal treatment were combined.•After each stage, the APTES grafting conversions were 25.3%, 50.7% and 80.6%.•High density of 13.48APTESnm−2 was silanized on the silica particle surface.•Reaction of APTES on silica surface was reversible in the thermal treatment.
A novel and efficient process was developed for high density silanization of nano-silica particles using APTES, in which 13.48APTESnm−2 was achieved. This process comprises three stages, namely, aqueous mixing, spray drying and thermal treatment. After the successive stages, the APTES conversions were 25.3%, 50.7% and 80.6%. In the aqueous mixing stage, the chemical reaction was fast and quite limited. In the spray drying stage, APTES was distributed on the surface of nano-silica particles uniformly by both physical and chemical adsorption. In the thermal treatment stage, the processing temperature (T) and time in the thermal treatment had large effects on the grafting density, and the reaction was reversible. When T<300°C, the reverse reaction dominated, causing a decrease of APTES grafting density. When T>300°C, the forward reaction dominated, leading to increased grafting density. The optimum processing temperature and time for high grafting density were 360°C and 30min, respectively.
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•A high-capacity iron oxide adsorbent with low cost was prepared.•Ethanol treatment changed adsorbent microstructure and inhibited crystallization.•Ethanol treatment increased surface ...area and adsorption capacity significantly.•Adsorption occurred by exchange of F− with OH− groups on adsorbent surface.•Achieved high F− adsorption in wide pH range and in the presence of co-anions.
A novel iron oxide adsorbent with a high fluoride adsorption capacity was prepared by a facile wet-chemical precipitation method and ethanol treatment. The ethanol-treated adsorbent was amorphous and had a high specific surface area. The adsorption capacity of the treated adsorbent was much higher than that of untreated adsorbent. The Langmuir maximum adsorption capacity of the adsorbent prepared at a low final precipitation pH (≤9.0) and treated with ethanol reached 60.8mg/g. A fast adsorption rate was obtained, and 80% of the adsorption equilibrium capacity was achieved within 2min. The adsorbent had high fluoride-removal efficiency for water in a wide initial pH range of 3.5–10.3 and had a high affinity for fluoride in the presence of common co-anions. The ethanol treatment resulted in structure transformation of the adsorbent by inhibiting the crystallization of the nano-precipitates. The adsorption was confirmed to be ion exchange between fluoride ions and the hydroxyl groups on the adsorbent surface.
Coupling of the synthesis and surface modification processes for hydrophobic or functionalized nano-silica particles was performed. Highly hydrophobic and high-density amino-functionalization were ...achieved for the nano-silica particles via the coupled process using SDS and APTES as modifiers, respectively. The coupled process was proven more effective than the non-coupled process.
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The processes of synthesis and surface modification were coupled herein to produce hydrophobic or functionalized nano-silica particles. Nano-silica particles with a spherical shape approximately 20 nm in diameter were synthesized. Nano-silica particles with high hydrophobicity were produced by coupling the synthesis with a modification process involving aqueous mixing, spray-drying, and thermal treatment, using the common surfactant sodium dodecyl sulfate (SDS) as a modifier. Amino-functionalized nano-silica particles with high grafting density were produced via the same process using the silane coupling agent γ-aminopropyltriethoxysilane (APTES). The modification was more effective with the coupled process than with the non-coupled process.
A novel bimetallic oxide adsorbent was synthesized by the co-precipitation of Fe(II) and Ti(IV) sulfate solution using ammonia titration at room temperature. The influences of the washing and drying ...methods, Fe/Ti molar ratio, and calcination temperature used in the preparation on the morphology, crystallization, surface structure and adsorption capacity were investigated. An optimized Fe―Ti adsorbent had a Langmuir adsorption capacity of 47.0mg/g, which was much higher than that of either a pure Fe oxide or Ti oxide adsorbent. There was a synergistic interaction between Fe and Ti in which Fe―O―Ti bonds on the adsorbent surface and hydroxyl groups provide the active sites for adsorption, and Fe―O―Ti―F bonds were formed by fluoride adsorption. The novel Fe―Ti adsorbent is efficient and economical for fluoride removal from drinking water.
A novel Fe―Ti oxide nano-adsorbent was synthesized by co-precipitation, which had a Langmuir adsorption capacity of 47.0mg/g at optimized condition. The Fe―O―Ti bond in the Fe―Ti adsorbent supported the active site (Fe―O―Ti―OH) for fluoride adsorption by forming a Fe―O―Ti―F bond on the adsorbent surface. Display omitted
► A novel and costless Fe―Ti oxide nano-adsorbent was synthesized. ► The optimized Fe―Ti adsorbent had a Langmuir adsorption capacity of 47.0mg/g. ► Fe and Ti in the adsorbent showed a remarkable synergistic interaction. ► The formed Fe―O―Ti in Fe―Ti adsorbent provided active sites of Fe―O―Ti―OH.
Nano silica particle was modified to produce hydrophobic surface with contact angle of 107° using the water soluble SDS as a modifier through a new route. The grafted density reached 1.82–2nm. ...Brønsted acid sites supply proton to react with SDS via generating carbocation, forming a Si–O–C structure.
•Silica was modified to produce hydrophobic surface using SDS as modifier.•The route is free of organic solvent and gets perfect contact of SDS and silica.•Contact angle of modified silica particles reached 107°.•Grafted density on the silica surface reached 1.82 SDS nm−2.•Brønsted acid sites supply proton to react with SDS via generating carbocation.
Hydrophobic silica particles were prepared using the surfactant sodium dodecyl sulfate (SDS) as a modifier by a new route comprising three processes, namely, aqueous mixing, spray drying and thermal treatment. Since SDS dissolves in water, this route is free of an organic solvent and gave a perfect dispersion of SDS, that is, there was excellent contact between SDS and silica particles in the modification reaction. The hydrophobicity of the modified surface was verified by the contact angle of the nano-sized silica particles, which was 107°. The SDS grafting density reached 1.82nm−2, which is near the highest value in the literature. The optimal parameters of the SDS/SiO2 ratio in the aqueous phase, process temperature and time of thermal treatment were determined to be 20%, 200°C and 30min, respectively. The grafting mechanism was studied by comparing the modification with that on same sized TiO2 particles, which indicated that the protons of the Brønsted acid sites on the surface of SiO2 reacted with SDS to give a carbocation which then formed a Si–O–C structure. This work showed that the hydrophilic surface of silica can be modified to be a hydrophobic surface by using a water soluble modifier SDS in a new modification route.
The dispersibility of silica sol particles modified by γ-methacryloxy propyl trimethoxyl silane (γ-MPS) in an ethanol–water mixed solvent was investigated. In the modification process, the ...hydrolysate of γ-MPS condensed to form oligomers, which further formed hydrogen bonds with the hydroxyl groups on the surface of the silica sol particles to cause agglomeration. Increasing the ethanol concentration inhibited the hydrolysis of γ-MPS and the formation of oligomers, thus inhibiting the agglomeration of silica sol particles. When the ethanol concentration was above 74 wt%, the γ-MPS-modified silica sol slurry was transparent and with a TEM image in a single-particle dispersed state. The dispersibility of the silica sol particles was determined by a double electric layer repulsion mechanism before modification and a steric hindrance mechanism by organic molecules grafted on the surface of the particles after modification. The grafting density of γ-MPS on the surface of silica sol particles affected the hydrophobicity of the modified particles, which can be effectively controlled.
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•High ethanol concentration facilitates high dispersibility of particles.•High ethanol concentration inhibits γ-MPS hydrolysis and particle agglomeration.•Modified particles are single-particle dispersed by steric-hindrance.•Particle hydrophobicity has a positive correlation with γ-MPS grafting density.
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