Summary

Physics advocates research on unifying chemical bonds and recognized parallels on a different (and non-reductive) level, as per the concept of the Great Unification of Forces in Nature. From this perspective, a Physicochemical Grand Unification of Forces would be a worthy project for humankind in order to increase our undertanding of existence and to improve our lives. This entry collection aims to present an account of chemical bonds and interactions in nano- to maco-environments.

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Topic Review
Thia-Michael Reaction
While the Michael addition has been employed for more than 130 years for the synthesis of a vast diversity of compounds, the reversibility of this reaction when heteronucleophiles are involved has been generally less considered. First applied to medicinal chemistry, the reversible character of the hetero-Michael reactions has been explored for the synthesis of Covalent Adaptable Networks (CANs), in particular the thia-Michael reaction and more recently the aza-Michael reaction. In these cross-linked networks, exchange reactions take place between two Michael adducts by successive dissociation and association steps. In order to understand and precisely control the exchange in these CANs, it is necessary to get an insight into the critical parameters influencing the Michael addition and the dissociation rates of Michael adducts by reconsidering previous studies on these matters. 
  • 2.8K
  • 28 Nov 2022
Topic Review
Polymeric Emissive Materials Based on Dynamic Covalent Bonds
Dynamic covalent polymers, composed of dynamic covalent bonds (DCBs), have received increasing attention due to their adaptive and reversible nature compared with common covalent linked polymers. Incorporating the DCBs into the polymeric material endows it with advanced performance including self-healing, shape memory property, and so forth.
  • 1.5K
  • 25 Nov 2022
Topic Review
Reactive Species on Amino Acids
Reactive oxygen species ROS can be triggered by exogenous sources (tobacco, pollution, xenobiotics, drugs, ionizing radiation and so on), but they can also be generated inside the cell by two different mechanisms: enzymatic and non-enzymatic; in both cases, they can have irreversible effects on animal and plant cells and tissues. The superoxide anion •O2− is unstable and cannot pass through membranes, but is rapidly converted to hydrogen peroxide H2O2 and it is membrane-permeable. In the Fenton reaction, H2O2 produces the hydroxyl radical •OH + −OH, which is highly reactive in the mitochondrial matrix. Elevated levels of ROS lead to increased mtDNA damage.
  • 2.0K
  • 23 Nov 2022
Topic Review
Supramolecular Combination Therapy Based on Metal Coordination Complexes
Supramolecular combination therapy adopts supramolecular materials to design intelligent drug delivery systems with different strategies for cancer treatments. Thereinto, macrocyclic supramolecular materials play a crucial role in encapsulating anticancer drugs to improve anticancer efficiency and decrease toxicity towards normal tissue by host–guest interaction. Biomacromolecule drugs have become one of the important medications for the therapeutics of human diseases. The choice of an adequate drug delivery method is essential to ensuring the therapeutic efficacy of biomacromolecule medications in vivo due to the high tendency of biomacromolecule pharmaceuticals to degrade in the human body.
  • 1.2K
  • 18 Nov 2022
Topic Review
Energy Transition to Achieve Carbon Neutrality
Successful energy transitions, also referred to as leapfrog development, present enormous prospects for EU nations to become carbon neutral by shifting from fossil fuels to renewable energy sources. Along with climate change, EU countries must address energy security and dependency issues, exacerbated by factors such as the COVID-19 pandemic, rising energy costs, conflicts between Russia and Ukraine, and political instability. Central European countries may transition to a clean energy economy and become carbon neutral on economic and strategic levels by locating alternative clean energy supply sources, reducing energy use, and producing renewable energy. 
  • 1.7K
  • 10 Nov 2022
Topic Review
SpyCatcher-SpyTag System
The SpyCatcher-SpyTag system was developed as a method for protein ligation. It is based on a modified domain from a Streptococcus pyogenes surface protein (SpyCatcher), which recognizes a cognate 13-amino-acid peptide (SpyTag). Upon recognition, the two form a covalent isopeptide bond between the side chains of a lysine in SpyCatcher and an aspartate in SpyTag. This technology has been used, among other applications, to create covalently stabilized multi-protein complexes, for modular vaccine production, and to label proteins (e.g., for microscopy). 
  • 9.7K
  • 19 Oct 2022
Topic Review
Reverse Water Gas Shift Reaction
The catalytic conversion of CO2 to CO by the reverse water gas shift (RWGS) reaction followed by well-established synthesis gas conversion technologies could be a practical technique to convert CO2 to valuable chemicals and fuels in industrial settings. For catalyst developers, prevention of side reactions like methanation, low-temperature activity, and selectivity enhancements for the RWGS reaction are crucial concerns. Cerium oxide (ceria, CeO2) has received considerable attention due to its exceptional physical and chemical properties. 
  • 6.5K
  • 09 Oct 2022
Topic Review
Nickel Nanoparticles
Methicillin-resistant Staphylococcus aureus (MRSA) has evolved vast antibiotic resistance. These strains contain numerous virulence factors facilitating the development of severe infections. Considering the costs, side effects, and time duration needed for the synthesis of novel drugs, seeking efficient alternative approaches for the eradication of drug-resistant bacterial agents seems to be an unmet requirement. Nickel nanoparticles (NiNPs) have been applied as prognostic and therapeutic cheap agents to various aspects of biomedical sciences. Their antibacterial effects are exerted via the disruption of the cell membrane, the deformation of proteins, and the inhibition of DNA replication. NiNPs proper traits include high-level chemical stability and binding affinity, ferromagnetic properties, ecofriendliness, and cost-effectiveness. They have outlined pleomorphic and cubic structures. The combined application of NiNPs with CuO, ZnO, and CdO has enhanced their anti-MRSA effects. The NiNPs at an approximate size of around 50 nm have exerted efficient anti-MRSA effects, particularly at higher concentrations. NiNPs have conferred higher antibacterial effects against MRSA than other nosocomial bacterial pathogens. The application of green synthesis and low-cost materials such as albumin and chitosan enhance the efficacy of NPs for therapeutic purposes.
  • 1.2K
  • 20 Sep 2022
Topic Review
The Mechanism-Based Inactivation of CYP3A4 by Ritonavir
Ritonavir is the most potent cytochrome P450 (CYP) 3A4 inhibitor in clinical use and is often applied as a booster for drugs with low oral bioavailability due to CYP3A4-mediated biotransformation, as in the treatment of HIV (e.g., lopinavir/ritonavir) and more recently COVID-19 (Paxlovid or nirmatrelvir/ritonavir). Ritonavir is clearly a potent mechanism-based inactivator, which irreversibly blocks CYP3A4. 
  • 2.4K
  • 19 Sep 2022
Topic Review
Carbon Nanotube Electrodes for Flexible Supercapacitors
Carbon nanotubes (CNTs), long recognized for their mechanical toughness, with an elastic strain limit of up to 20%, are regarded as potential candidates for FSC electrodes. Along with excellent mechanical properties, high electrical conductivity, and large surface area, their assemblage adaptability from one-dimensional fibers to two-dimensional films to three-dimensional sponges makes CNTs attractive. 
  • 1.6K
  • 19 Aug 2022
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