MXene nanomaterials have sparked significant interest among interdisciplinary researchers to tackle today's medical challenges. In particular, colloidal MXene quantum dots (MQDs) offer the high ...specific surface area and compositional flexibility of MXene while providing improvements to aqueous stability and material–cell interactions. The current study for the first time reports the development and application of immunoengineered tantalum‐carbide (Ta4C3Tx) MQDs for in vivo treatment of transplant vasculopathy. This report comes at a critical juncture in the field as poor long‐term safety of other MXene compositions challenge the eventual clinical translatability of these materials. Using rational design and synthesis strategies, the Ta4C3Tx MQDs leverage the intrinsic anti‐inflammatory and antiapoptotic properties of tantalum to provide a novel nanoplatform for biomedical engineering. In particular, these MQDs are synthesized with high efficiency and purity using a facile hydrofluoric acid‐free protocol and are enriched with different bioactive functional groups and stable surface TaO2 and Ta2O5. Furthermore, MQDs are spontaneously uptaken into antigen‐presenting endothelial cells and alter surface receptor expression to reduce their activation of allogeneic T‐lymphocytes. Finally, when applied in vivo, Ta4C3Tx MQDs ameliorate the cellular and structural changes of early allograft vasculopathy. These findings highlight the robust potential of tailored Ta4C3Tx MQDs for future applications in medicine.
The development and application of new immunoengineered tantalum‐carbide (Ta4C3Tx) MXene quantum dots (MQDs) for the treatment of transplant vasculopathy are reported. Using rational design and novel synthesis strategies, these MQDs possess intrinsic anti‐inflammatory properties. These findings highlight the robust potential of smart Ta4C3Tx MQDs for future applications in biomedical engineering and nanomedicine.
Hydrofluoric acid (HF) is commonly used for conditioning the glass ceramics either prior to cementation or for intraoral repair in prosthetic and restorative dentistry. The present study offers a ...review of chemical properties of HF used, highlight the possible hazardous effects of this agent, and to recommend the treatment approach for potential risks. Available published information documented in PubMed, Medline, and Picarta literature databases was reviewed. Additional information was derived from scientific reports, medical and chemical textbooks, handbooks, product information, manufacturers’ instructions, Internet web sites of the HF manufacturers. No report was found on the incidence of the hazardous effects of HF in dentistry. Reports from other fields presented incidences of acute and chronic symptoms in exposure to HF. While acute symptoms include skin or nail burns, chronic ones involve systemic toxicity, eye injuries, inhalation and ingestion-related symptoms that can be even fatal. HF can be harmful and particularly aggressive to soft tissues, but symptoms may not be apparent immediately after exposure. The hazardous effects are not based on the pH value, but on the toxicity of HF. Potential hazards of HF known from other applications than dentistry should be considered also in dental applications. Especially the clinicians, who often deal with adhesive cementation or repair of glass ceramics, should take necessary precautions for possible hazards of HF.
•Corrosion and stress corrosion cracking behavior of Q345R in HF solution is studied.•The corrosion products have no protection effect on the matrix.•Pits forms due to hydrogen escaping and uneven ...distribution of corrosion products.•The impacts of stress on corrosion crack initiation and propagation are different.
To explore the corrosion behavior of carbon steel at medium hydrofluoric acid concentration, the corrosion and stress corrosion cracking behavior of Q345R in 40 wt.% hydrofluoric acid are investigated. An almost constant corrosion rate is observed which is attributed to the loose structure of corrosion products that cannot prevent fluorion from penetrating. Pits are found as a consequence of hydrogen escaping and uneven distribution of corrosion products. These pits transform into cracks during stress corrosion cracking, and the higher the stress, the shorter the pit-to-crack transition time, while the change in crack propagation rate with stress is different.
Since their discovery in 2011, the number of 2D transition metal carbides and nitrides (MXenes) has steadily increased. Currently more than 40 MXene compositions exist. The ultimate number is far ...greater and in time they may develop into the largest family of 2D materials known. MXenes’ unique properties, such as their metal‐like electrical conductivity reaching ≈20 000 S cm−1, render them quite useful in a large number of applications, including energy storage, optoelectronic, biomedical, communications, and environmental. The number of MXene papers and patents published has been growing quickly. The first MXene generation is synthesized using selective etching of metal layers from the MAX phases, layered transition metal carbides and carbonitrides using hydrofluoric acid. Since then, multiple synthesis approaches have been developed, including selective etching in a mixture of fluoride salts and various acids, non‐aqueous etchants, halogens, and molten salts, allowing for the synthesis of new MXenes with better control over their surface chemistries. Herein, a brief historical overview of the first 10 years of MXene research and a perspective on their synthesis and future development are provided. The fact that their production is readily scalable in aqueous environments, with high yields bodes well for their commercialization.
The transition metal carbides and nitrides (MXenes) are among the largest 2D material families. MXenes’ unique properties, such as their metal‐like electrical conductivity, render them quite useful in a large number of applications including energy storage, optoelectronic, biomedical, communications, and environmental. A brief historical overview of the first 10 years of MXene research and a perspective on their synthesis and future development are provided.
The exothermic F + H(2)O → HF + OH reaction has a decidedly "early" or "reactant-like" barrier. According to a naïve interpretation of the Polanyi's rules, translational energy would be more ...effective than vibrational energy in promoting such reactions. However, we demonstrate here using both quasi-classical trajectory and full-dimensional quantum wave packet methods on an accurate global potential energy surface that excitations in the H(2)O vibrational degrees of freedom have higher efficacy in enhancing the reactivity of the title reaction than the same amount of translational energy, thus providing a counter-example to Polanyi's rules. This enhancement of reactivity is analyzed using a vibrational adiabatic model, which sheds light on the surprising mode selectivity in this reaction.
Abstract In Fluorpolymeren sind die Wasserstoffatome in einer Polymerkette zum Großteil oder auch vollständig durch Fluor ersetzt, was zu einer Reihe besonderer Eigenschaften wie hoher chemischer und ...thermischer Beständigkeit führt. Aufgrund dieser Eigenschaftskombination sind diese Hochleistungspolymere für manche Anwendungen nicht oder nur schwer ersetzbar. Sonderwerkstoffe wie Fluorpolymere nehmen aufgrund ihrer chemischen Zusammensetzung, ihres geringen Marktvolumens und der meist industriellen Anwendung eine Sonderstellung ein, da sie nicht zusammen mit Massenpolymeren wie z. B. Polyethylen am Ende des Lebenszyklus anfallen und auch nicht zusammen recycelt werden können. In diesem Beitrag werden verschiedene Verfahren hinsichtlich ihres technischen Reifegrades und ihrer Eignung diskutiert, um Fluorpolymere vollständig zu recyceln.
Abstract In fluoropolymers, a large portion or even all of the hydrogen atoms in a polymer chain are replaced by fluorine, which results in a number of special properties such as high chemical and temperature resistance. As a result of this combination of properties, these high‐performance polymers are not replaceable, or only with difficulty, for some applications. The recycling of polymers and the associated closing of material loops is an essential development task for the entire polymer industry. Materials such as fluoropolymers have a special position due to their chemical composition and their low market volume, as they cannot be recycled together with other bulk polymers at the end of their life cycle. This paper discusses different processes in terms of their technical maturity and suitability to allow fluoropolymers to be fully recycled.
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