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Chemists at the University of Tokyo have created a new kind of chemical bond, a covalent bond that relies on a single electron. This bond, which was first proposed by chemist Linus Pauling in 1931, has been difficult to create in the past due to the instability of the resulting bonds. However, the researchers were able to stabilize the bond long enough to analyze it using X-rays and light. This discovery could potentially lead to the creation of new families of molecules. [Extracted from the article]

• The introduction of magnetic nanoparticles on all-carbon skeletons without coordination atoms for electromagnetic absorption. • One-step synthesis of conjugated ferrocene microporous polymers via Suzuki reaction. • Fe-P-XC is highly thermally stable. • The minimum reflection loss and effective absorption bandwidth of Fe-P-2C get -58.66 dB and 6.28 GHz, respectively. • Application of conjugated microporous polymers for electromagnetic wave absorption. Coordination bonds are relatively unstable compared to covalent bonds, and common carbon-based absorbing material precursors are bonded in the form of coordination bonds. In this work, we have introduced ferrocene units into conjugated microporous polymers (CMP) in one step by Suzuki reaction. By adjusting the proportion of ferrocene units, a series of magnetic Fe-C nanocomposites (Fe-P-XC) derived from conjugated ferrocene polymers without heteroatom doping (N, S, P, etc.) were formed. The Fe-P-2C composite has good absorption properties with minimum reflection loss at 4.4 GHz (-58.66 dB) and effective absorption bandwidth (EAB) of 6.28 GHz at 2.4 mm (11.72–18 GHz). Compared with the precursor materials formed by coordination bonds, the present work reveals the electromagnetic wave absorption mechanism of carbon-based materials without heteroatom doping through a simple and effective strategy. [Display omitted] [ABSTRACT FROM AUTHOR]

• A Si-based anode with a hierarchical pomegranate-structure (HPS-Si) was designed to modulate the stress variation. • The sub-micronized hierarchical pomegranate-structure can provide suitable buffer space and avoid agglomerates during cycling. • SiO 2– x , and SiC modifications of Si nanosphere as flexible and rigid layers, can reduce the surface stress of conductive carbon layers for avoiding cracking. • The covalent bonding immensely strengthens the link of the modification with Si nanospheres, thus resisting stress effects. Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity. However, large stress during (de)lithiation induces severe structural pulverization, electrical contact failure, and unstable solid-electrolyte interface, which hampers the practical application of Si anode. Herein, a Si-based anode with a hierarchical pomegranate-structure (HPS-Si) was designed to modulate the stress variation, and a sub-micronized Si-based sphere was assembled by the nano-sized Si nanospheres with sub-nanometer-sized multi-phase modification of the covalently linked SiO 2– x , SiC, and carbon. The sub-micronized HPS-Si stacked with Si nanospheres can avoid agglomerates during cycling due to the high surface energy of nanomaterials. Meanwhile, the reasonable pore structure from SiO 2 reduction owing to density difference is enough to accommodate the limited volume expansion. The Si spheres with a size of about 50 nm can prevent self-cracking. SiO 2– x , and SiC as flexible and rigid layers, have been synergistically used to reduce the surface stress of conductive carbon layers to avoid cracking. The covalent bonding immensely strengthens the link of the modification with Si nanospheres, thus resisting stress effects. Consequently, a full cell comprising an HPS-Si anode and a LiCoO 2 cathode achieved an energy density of 415 Wh kg−1 with a capacity retention ratio of 87.9% after 300 cycles based on the active materials. It is anticipated that the hierarchical pomegranate-structure design can provide inspiring insights for further studies of the practical application of silicon anode. [Display omitted] [ABSTRACT FROM AUTHOR]

The article focuses on several ways to bond atoms. The basic types of chemical bond are covalent, ionic and metallic. A fourth type of bond is known as hydrogen bond, which is described as an electrostatic attraction between hydrogen atoms and areas of high electron density. Described are several instances affecting prevailing wisdom about bonds including incipient or wannabe metals, phantom bonds, loops and links, muon glue and a thermodynamic quantity that is seen as promoting disorder.

• There exists a continuous oxide layer on the irregular HDH Ti powder surface. • CaB 6 addition promotes the improved sintered density and refines the grain size. • The scavenging of O by CaB 6 addition makes a high strength and superior ductility for α-Ti alloy. The challenge of producing a high-ductility titanium (Ti) material using inexpensive high-oxygen hydride-dehydride (HDH) Ti powder is hereby addressed by the incorporation of CaB 6 oxygen-scavenger. The oxygen-scavenging behavior, microstructure evolution, mechanical behavior and improvement mechanism were systematically investigated. A continuous TiO 2 oxide layer with a thickness of approximately 9.3 nm is presented on the HDH Ti powder surface. The oxide layer will dissolve into Ti matrix during sintering, making the increase of c / a value and leading to the Ti-Ti bonds developing from plastic metal bonds toward brittle covalent bonds. The CaB 6 addition can scavenge O impurity and make a significant increase in tensile ductility for α-Ti matrix. A small addition of 0.2 wt.% CaB 6 provides a superior tensile elongation of 22.2% for Ti material, almost three times as high as that of pure Ti (7.5%). The increase of deformation twining activity and grain refinement are responsible for the improved ductility. Furthermore, the CaB 6 oxygen-scavenger can react with the surface oxide layer to in-situ form rod-like TiB and granular CaTiO 3 reinforcements, refining the coarse near equiaxed grain of α-Ti matrix into fine equiaxed crystals. The multiple mechanisms of grain-boundary strengthening, load-bearing strengthening of TiB and Orowan strengthening of CaTiO 3 nanoparticles work together to increase the tensile strength of Ti/CaB 6 composites. This work offers an effective method to fabricate high-performance Ti material using inexpensive high-oxygen HDH Ti powder. [Display omitted] [ABSTRACT FROM AUTHOR]

A patent has been issued to Biomea Fusion Inc. for irreversible inhibitors of menin-MLL interaction. The patent describes specific heterocyclic irreversible inhibitors of menin-MLL or MLL fusion proteins interaction, as well as methods for synthesizing these inhibitors and using them in the treatment of diseases. The compounds described in the patent form a covalent bond with a cysteine residue on menin and have potential therapeutic applications. For more information, refer to the patent number 12077544 filed on January 9, 2023, and published online on September 3, 2024. [Extracted from the article]

A recent study conducted by researchers at GLA University in Mathura, India, explored the potential of using Mn-doped graphyne as a drug delivery system for propylthiouracil (PTU), an antineoplastic drug. The study found that the doping of Mn metal into the graphyne surface significantly increased the adhesion energy of PTU and improved its ability to attach to the Mn-doped graphyne. The researchers also observed changes in the reaction mechanism of PTU with Mn-doped graphyne in the acidic environment of cancer cells. This theoretical study provides insights into the potential use of Mn-doped graphyne as a drug delivery system in cancer therapy. [Extracted from the article]

The article discusses chemistry topics including classification of elements and periodicity in properties. Topics include chemical bonding and molecular structure, Lothar Meyer's atomic volume curve, Mendeleev's periodic law, ionic bond as the electrostatic force of attraction between cation and anion formed by complete transfer of electrons from one atom to another, and covalent bond.

A report from Hebei University in Baoding, China discusses the interaction between polyphenols and polysaccharides in food processing and storage. Polyphenols, which are found in various foods, have unique structures and biological activities that make them of interest to the food industry and nutrition. However, their health benefits can be compromised due to their structural instability. The report aims to review the mechanisms and factors influencing the interaction between polyphenols and polysaccharides, as well as summarize their applications in the food industry. The findings of this research can provide important theoretical support for the use of polyphenols and polysaccharides in food. [Extracted from the article]

A preprint abstract from biorxiv.org discusses the challenges in predicting the stability of photocrosslinking hydrogels used in tissue engineering and regenerative medicine. The authors propose a unique approach using 1H NMR spectra of enzymatically degraded hydrogels to measure the degree of crosslinking (DoC) and predict material stability under fluid flow. The study focuses on two types of photocrosslinkable hydrogels and reveals that a threshold DoC is required for stability, with smaller features requiring a higher DoC. The authors suggest that quantifying chemical crosslinks can aid in the design of advanced hydrogel materials for applications such as photopatterning and bioprinting. [Extracted from the article]

"Antecedent" by Juleta Severson-Baker is a collection of poetry that explores themes of mid-life ennui, familial relationships, and the loss of parents. The poems are characterized by scientific and somatic diction, using vivid language to describe natural phenomena and emotions. While the subject matter is powerful and the language resonant, the use of inconsistent lower case and erratic stanza breaks can be distracting. The final section, "The Debbie Poems," could have benefited from further development of the central character. Overall, the poems in "Antecedent" are moving and contemplative, exploring the human experience and the inevitability of solitude. [Extracted from the article]

• Zn 2 SnO 4 , as a SnO 2 -based ternary oxide, can improve the arc resistance of Cu contact materials in comparison with SnO 2. • Zn 2 SnO 4 particles distribute uniformly on the eroded surface and enhance the electrical contact property. • The enhanced arc-resistance of Zn 2 SnO 4 /Cu contacts highly relies on the polar-covalent Cu-O bonds at the interfaces. • DFT calculations could be extended to the rational design of ternary oxides/Cu composites with high arc resistance. Interface wettability is a vital role in directly impacting the electrical contact characteristics of oxides/Cu-based composites under arc erosion. Exploring its influence mechanism, especially at atomic/electronic scales, is significant but challenging for the rational design of oxides/Cu contacts. Here, we designed Zn 2 SnO 4 /Cu electrical contacts aiming to solve the poor wettability of SnO 2 /Cu composites. It was found that Zn 2 SnO 4 could remarkably improve the arc resistance of Cu-based electrical contacts, which was benefited by the excellent interface wettability of Zn 2 SnO 4 /Cu. The characterization of eroded surface indicated that Zn 2 SnO 4 particles distributed uniformly on the contact surface, leading to stable electrical contact characteristic. Nevertheless, SnO 2 considerably deteriorated the arc resistance of SnO 2 /Cu composite by agglomerating on the surface. The effect mechanism of wettability on arc resistance was investigated through density function theory (DFT) study. It revealed that strong polar covalent bonds across the Zn 2 SnO 4 /Cu interface contributed to improving the interfacial adhesion strength/wettability and thus significantly enhanced the arc resistance. For binary SnO 2 /Cu interface, ionic bonds resulted in weak interface adhesion, giving rise to deterioration of electrical contact characteristic. This work discloses the bonding mechanism of oxide/Cu interfaces and paves an avenue for the rational design of ternary oxide/Cu-based electrical contact materials. [ABSTRACT FROM AUTHOR]

• One-pot method was used to synthesize covalent cross-linking photocatalyst of ultrathin MoS 2 and sulfur-doped carbon nitride (MS/SCN-x%). • The MS/SCN hybrids have ultrathin lamellar structure and the nanosheets are arranged in an array-like structure. • The UV–vis absorption spectra of MS/SCN hybrids have two noticeable shoulder, proving MoS 2 has an ultrathin structure. • The introduction of cyano group in SCN can enhance the visible light absorption capacity and help to improve the photocatalytic reaction. • The MS/SCN-2.5% hybrids drastically improved HER performance, over original MoS 2 nanosheet modified SCN, also rivaled with Pt/SCN.. Constructing noble-metal-free loaded catalyst with high-efficiency photocatalytic activity by a simple and scalable method is of profound significance for fundamental research and practical application. Herein, a simple one-pot method was used to synthesize novel samples of array-like sulfur-doped graphitic carbon nitride (SCN) nanosheets with ultrathin MoS 2 loading (MS/SCN-x%). The ultrathin MoS 2 cocatalyst was evenly distributed on the surface of SCN and was linked to the main catalyst by covalent chemical bonds. Benefited from the multiple advantages of the array-like porous nanosheets structure with rich exposed surface, covalent cross-linking structure, and enhanced visible light absorption, the MS/SCN-2.5 % composites drastically improve hydrogen evolution performance, which is superior to original MoS 2 nanosheet modified by two-step mixing method, and also rivals with Pt/SCN. The designing strategy of photocatalyst modified by noble-metal-free cocatalyst with covalent bond structure provides fascinating insights into enhanced photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

A preprint abstract from biorxiv.org discusses the use of bacteriophages, viruses that target and kill bacteria, as a potential treatment for multidrug-resistant wound infections. The challenge lies in delivering sufficient concentrations of active phages directly to the infection site. The researchers present HydroPhage, an injectable hydrogel system that encapsulates high concentrations of phages and achieves controlled release over a week, surpassing current clinical dosages. In a preclinical mouse model, localized and repeated phage dosing resulted in enhanced bacterial clearance, despite the emergence of bacterial resistance. This research contributes to the development of wound dressings tailored for resistant infections. [Extracted from the article]

Various orientations and diffraction patterns from nanoscale Al precipitates in eutectic Si were investigated by high-resolution transmission electron microscopy combined with transition matrix and stereographic projection. It was found that the Al precipitates had 12 variants, all orientation relationships can be expressed as: (001)Al//{111}Si, [110]Al//< 1 ¯ 10 >Si. Further, a new diffraction pattern model from Al precipitates was established under [111]Si zone axis, which was in good agreement with the experiment data. The microstructure, adhesion strength and electronic structure of the interface between Al precipitate and Si matrix were studied by first-principles calculation and experimental observation. The results show that the covalent bonds are formed between interfacial Al and Si atoms, which play a key role in interfacial bind strength. Based on the Griffith fracture theory, the cracks tend to form and expand in the interior of Al precipitates firstly, and the interfaces can act as a protective layer to prevent crack propagation. Therefore, the nanoscale Al precipitates will improve the toughness of eutectic Si particles by releasing part of stress through lattice distortion. In addition, the stretched nanoscale Al precipitates can act as effective heterogeneous nucleation sites for high density deformation nanotwins in eutectic Si during deformation, which significantly improved the deformability of eutectic Si. [ABSTRACT FROM AUTHOR]

The precipitation sequence in Al-Cu-Li alloys is sensitively dependent on the Cu/Li ratio. In the low ratio Cu/Li alloys of 1–2.5, the δ' phases usually nucleate and grow from the θ' precipitates, forming δ'/θ'/δ' composite precipitates. In this work, we present a first-principle study on atomic structures and their relative stabilities of the growing δ'/θ'/δ' composite precipitates in Al-Cu-Li alloys. Based on the analysis of the interface formation energy, constituted interface and coherent strains energies, an "anti-phase 1/2[110]" relationship for the opposite δ' has been proposed when the inward θ' has an odd number of Cu-layers. It may be achieved by translating one side of the δ' by 2 /2 a along the [110] slip direction, which is an energetically most favorable path. By analyzing the bonding characteristics, both the "zigzag Al-Li combined with Cu" and the "zigzag Al-Al" interfacial terminals are found to control the interface structure of the growing δ'/θ'/δ'. According to the calculated ideal tensile strength, the "anti-phase 1/2 [110]" structure is most stable to some extent. When Li atoms at the interface enter decohesion mode along the applied strain, the stable δ'/θ'/δ' is prone to failure because of relatively weak Li-Al covalent bonds. Therefore, the really thin δ' in δ'/θ'/δ' composite precipitates may be explained by the continuous disassociation of Li atoms from the interface. In addition, a very weak Cu-Li covalent bond was suggested in the δ'/θ'/δ' composite precipitates. This is in sharp contrast to previous reports. [ABSTRACT FROM AUTHOR]

This review summarized the factors that influence the active sites of g-C 3 N 4 , including basal engineering and hybrid engineering. The relationship between the active sites in g-C 3 N 4 and their influencing factors is described. We discussed the application of g-C 3 N 4 rich in active sites in photocatalysis by the following modifications: morphology, surface treatment, heteroatom doping, and interfacial interaction. With the development in photocatalysis field, photocatalysts have received increasing attention due to their important role in environmental pollution and energy crisis. As a nonmetallic photocatalyst, graphitic carbon nitride (g-C 3 N 4) has been widely recognized because of its excellent optical properties, low cost, and environment friendliness. In the g-C 3 N 4 intrinsic frameworks, carbon atom tends to be the reducing active site, while nitrogen atom tends to be the oxidizing active site and reducing active site according to the difference of electronegativity. However, the quantity and quality of these active sites are affected by many factors, including C N covalent bonds, surface properties, etc. Active sites play an important role in photocatalysis; however, this role is not detailed in most reports. In this review, we proposed the following possible mechanisms of active sites in improving the photocatalytic activity of traditional g-C 3 N 4 based on its intrinsic: morphology regulation, carrier migration, surface active treatment, and substrate adsorption. The following factors affecting the active sites of g-C 3 N 4 , including basal engineering and hybrid engineering, were also investigated. The roles of these active sites in improving the photocatalytic activity of g-C 3 N 4 -based photocatalytic materials, including morphology regulation, surface treatment, heteroatom doping, and interfacial interaction, were also expounded. Current challenges and future development of g-C 3 N 4 -based photocatalysts that are rich in active surface sites were also discussed. This review provides an in-depth understanding of g-C 3 N 4 -based photocatalysts. [ABSTRACT FROM AUTHOR]

Organic coatings are the most widely employed approach for the promotion of corrosion resistance of magnesium (Mg) alloys. Unfortunately, traditional organic coatings are weakly bonded to Mg substrates due to physical adsorption. Herein, a polyethylacrylate (PEA) coating was fabricated on Mg-Zn-Y-Nd alloy via electro-grafting. The surface structure and chemical composition were characterized by means of scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscope (AFM) and Fourier transform infrared (FTIR) as well as time of flight-secondary ion mass spectrometer (ToF-SIMS). The results showed that the surface roughness of PEA coating was dominated by scan rate; while the coverage and integrity of PEA coating were mainly affected by the monomer concentration and sweep circles. ToF-SIMS results indicated that PEA coating was wholly covered on Mg alloy, and the presence of C 2 H 3 Mg− fragment confirmed the covalent bond between PEA coating and Mg alloy. In addition, DFT calculation results of the adsorption of EA molecules with Mg substrate agree well with the experimental phenomena and observation, suggesting that the electrons in 3 s orbit of Mg atoms and 2p z orbit of C 1 atom participated in the formation of covalent bond between PEA coating and Mg substrate. Potentiodynamic polarization curves and immersion test demonstrated that the PEA coatings could effectively enhance the corrosion resistance of Mg alloy. The platelet adhesion results designated that platelets were barely visible on PEA coating, which implied that PEA coating could effectively prevent the thrombosis and coagulation of platelets. PEA coating might be a promising candidate coating of Mg alloy for cardiovascular stent. [ABSTRACT FROM AUTHOR]

Synergy effect of high stiffness and good damage tolerance is always the focus of the development of novel structural materials. Herein, a new strategy on the future damage tolerant material design is proposed to merge the strong covalent bonds into the easy shear deformed A 3 B metallic box. This goal is realized by studying 126 A 3 BX phases and establishing a database on their mechanical properties through high-throughput first principles calculations. The combination strategies of A 3 B metallic box and XA 3 octahedra show intensive influences on the expected mechanical properties. The family includes 49 quasi-ductile compounds. Among them, four compounds (Ti 3 AlN, Mn 3 CuN, Ti 3 TlN and Ni 3 SnN) exhibit excellent damage tolerance and the other six compounds (Mn 3 NiN, Mn 3 GaC, Mn 3 GaN, Mn 3 SnC, Cr 3 SnN, Co 3 AlC) show both damage tolerance and high stiffness. Their competitive high temperature properties are demonstrated through the detailed investigation on the typical cases of Co 3 AlC and Ti 3 TlN. This study leads a novel direction for the design of the future quasi-ductile and high stiffness ceramics. [ABSTRACT FROM AUTHOR]

A research report from Chonnam National University in Gwangju, South Korea discusses the development of biosensors for the detection of pathogenic organisms. The researchers have created a biosensor platform using N-heterocyclic carbene-graphene nanotransistors that show high sensitivity and specificity in detecting pathogens such as SARS-CoV-2, O. tsutsugamushi, and E. coli in clinical samples. The platform has the potential to be used as a rapid diagnostic tool during pandemics. The research has been peer-reviewed and published in Advanced Functional Materials. [Extracted from the article]

Combined quantum mechanical and molecular mechanical (QM/MM) methods play an important role in multiscale modeling and simulations. QMMM 2023 is a general-purpose program for single-point calculations, geometry optimizations, transition-state optimizations, and molecular dynamics (MD) at the QM/MM level. It calls a QM package and an MM package to perform the required single-level calculations and combines them into a QM/MM energy by a variety of schemes. QMMM 2023 supports GAMESS-US, Gaussian , and ORCA as QM packages and Tinker as the MM package. Four types of treatments are available for embedding the QM subsystem in the MM environment: mechanical embedding with gas-phase calculations of the QM region, electronic embedding that allows polarization of the QM region by the MM environment, polarizable embedding for mutual polarization of the QM and MM regions, and flexible embedding for both mutual polarization and partial charge transfer between the QM and MM regions. Boundaries between QM and MM regions that pass through covalent bonds can be treated by several methods, including the redistributed charge (RC) scheme, redistributed charge and dipole (RCD) scheme, balanced-RC scheme, balanced-RCD scheme, screened charge scheme that takes account of charge penetration effects, and smeared charge scheme that delocalizes the MM charges near the QM–MM boundary. Geometry optimization can be done using the optimizer implemented in QMMM 2023 or the Berny optimizer in Gaussian through external calls to Gaussian. Molecular dynamics simulations can be performed at the pure-MM level, pure-QM level, fixed-partitioning QM/MM level, and adaptive-partitioning QM/MM level. The adaptive-partitioning treatments permit on-the-fly relocation of the QM–MM boundary by dynamically reclassifying atoms or groups into the QM or MM subsystems. Program Title: QMMM 2023. CPC Library link to program files: https://doi.org/10.17632/zmkc9db4zj.1. Licensing provisions: Apache-2.0 for the program and CC-BY-4.0 for the manual. Programming languages: Fortran90, Perl, and shell scripting. Nature of problem: Multiscale modeling and simulations by the combined quantum mechanical and molecular mechanical (QM/MM) method. Solution method: The program performs single-point calculations, geometry optimizations, transition state optimizations, and molecular dynamics (MD) by the QM/MM method by interfacing calls to binary executables in a QM package (GAMESS-US, Gaussian, or ORCA) and an MM package (TINKER) for the required calculations. QMMM 2023 supports various types of embedding schemes and multiple ways of treating a QM-MM boundary passing through a covalent bond. Additional comments including restrictions and unusual features: (1) QMMM 2023 supports polarizable-embedding and flexible-embedding schemes based on the electronegativity equalization principle and allowing charge transfer between the QM and MM regions. (2) For a QM-MM boundary passing through covalent bonds, all link-atom-based treatments preserve the charge of the MM region (and MM bond dipoles if desired) while effectively avoiding the over-polarization of the QM region. Further tuning is available to account for the charge penetration effects at the QM-MM boundary. (3) For dynamics simulations, Hamiltonian-based adaptive-partitioning algorithms allow on-the-fly reclassification of atoms or groups into the QM or MM regions without abrupt changes in the energy of the entire system or in the forces on all atoms. [ABSTRACT FROM AUTHOR]

Researchers at Sidi Mohamed Ben Abdellah University in Fez, Morocco have conducted a study to find new inhibitors for enzymes involved in autoimmune diseases like rheumatoid arthritis. They used advanced computer-aided drug design techniques to create 3D-QSAR models and a pharmacophore model to identify potential inhibitors. Through molecular docking, pharmacokinetic assessments, and molecular dynamics simulations, they gained insights into the interactions between the inhibitors and the target enzymes. The study successfully identified potential inhibitor candidates for further investigation and contributes to our understanding of enzyme-inhibitor interactions for the development of more effective treatments for autoimmune conditions. [Extracted from the article]

A recent study conducted at the University of California San Diego (UCSD) has explored the use of genetic engineering to enhance the functionality of cell membrane-coated nanoparticles (CNPs). The researchers developed a modular approach to functionalizing CNPs by introducing a SpyCatcher membrane anchor that can form a covalent bond with various ligands modified with SpyTag. This technique was used to create three different targeted CNP formulations, which exhibited enhanced affinity towards specific cell lines and demonstrated effective targeting and growth suppression in a murine tumor xenograft model of ovarian cancer. The study suggests that genetic engineering offers a promising method for developing multifunctional CNPs for various biomedical applications. [Extracted from the article]

A report from South China Agricultural University discusses the development of fully bio-based thermosetting polyimine vitrimers, which have excellent adhesion, rapid self-healing, multi-recyclability, and antibacterial ability. Traditional thermosetting materials cannot be recycled or reprocessed, leading to environmental pollution. The researchers used renewable feedstocks to create covalent adaptive networks based on dynamic covalent bonds, addressing these shortcomings. The polyimine vitrimers showed fine mechanical properties, good thermal stability, and the ability to self-heal within 30 minutes at 80 degrees Celsius. They also exhibited antibacterial properties and could be recovered multiple times for repeated usage. This research provides a new strategy for the application of multifunctional bio-based polymer materials, particularly in adhesives. [Extracted from the article]

This patent application discusses the development of a single solution hydrogel system for medical applications. The current technology involves complex two-component systems that require specialized delivery devices. The inventors propose a single solution system that can form hydrogels in a convenient and reproducible manner without the need for separate components or external activation. This system has potential applications in controlled drug delivery, tissue augmentation, and intraluminal stenting, among others. The patent application provides detailed claims and specifications for the hydrogel precursor solution, which can be used in various medical procedures and dispensed using various devices. [Extracted from the article]

Keywords for this news article include: Suzhou Key Laboratory of Macromolecular Design and Precision Synthesis, Chirality, Health and Medicine. Keywords: Chirality; Health and Medicine EN Chirality Health and Medicine 1225 1225 1 10/30/23 20231103 NES 231103 2023 NOV 5 (NewsRx) -- By a News Reporter-Staff News Editor at Medical Devices & Surgical Technology Week -- A new study on chirality is now available. [Extracted from the article]

It was recently reported that thermosetting polymers can be fully dissolved in a proper organic solvent utilizing a bond-exchange reaction (BER), where small molecules diffuse into the polymer, break the long polymer chains into short segments, and eventually dissolve the network when sufficient solvent is provided. The solvent-assisted dissolution approach was applied to fully recycle thermosets and their fiber composites. This paper presents the first multi-scale modeling framework to predict the dissolution kinetics and mechanics of thermosets in organic solvent. The model connects the micro-scale network dynamics with macro-scale material properties: in the micro-scale, a model is developed based on the kinetics of BERs to describe the cleavage rate of polymer chains and evolution of chain segment length during the dissolution. The micro-scale model is then fed into a continuum-level model with considerations of the transportation of solvent molecules and chain segments in the system. The model shows good prediction on conversion rate of functional groups, degradation of network mechanical properties, and dissolution rate of thermosets during the dissolution. It identifies the underlying kinetic factors governing the dissolution process, and reveals the influence of different material and processing variables on the dissolution process, such as time, temperature, catalyst concentration, and chain length between cross-links. [ABSTRACT FROM AUTHOR]

Once in the intracellular environment, glutathione (GSH) could trigger a cascade reaction to release active CPT drugs to achieve chemotherapy, which could be further promoted by NIR light induced photothermal therapy. Keywords: Anhui; People's Republic of China; Asia; Anticancer Agents; Cancer; Cancer Therapy; Drugs and Therapies; Emerging Technologies; Health and Medicine; Nanoparticles; Nanotechnology; Oncology; Protective Agents; Risk and Prevention EN Anhui People's Republic of China Asia Anticancer Agents Cancer Cancer Therapy Drugs and Therapies Emerging Technologies Health and Medicine Nanoparticles Nanotechnology Oncology Protective Agents Risk and Prevention 769 769 1 08/14/23 20230815 NES 230815 2023 AUG 15 (NewsRx) -- By a News Reporter-Staff News Editor at Cancer Weekly -- Research findings on Nanotechnology - Nanoparticles are discussed in a new report. [Extracted from the article]

Keywords: Indianapolis; State:Indiana; United States; North and Central America; Life Science; Enzymes and Coenzymes; GTPase EN Indianapolis State:Indiana United States North and Central America Life Science Enzymes and Coenzymes GTPase 1109 1109 1 08/07/23 20230808 NES 230808 2023 AUG 11 (NewsRx) -- By a News Reporter-Staff News Editor at Drug Week -- Investigators publish new report on Life Science. Our news editors obtained a quote from the research from the Indiana University School of Medicine, "Previously we had reported an aryl sulfonyl fluoride fragment that formed a covalent bond at Tyr-82 on Ral and created a deep and well-defined pocket. [Extracted from the article]

Keywords: Yantai; People's Republic of China; Asia; Bioengineering; Biomedical Engineering; Biomedicine; Biotechnology; Health and Medicine; Tissue Engineering EN Yantai People's Republic of China Asia Bioengineering Biomedical Engineering Biomedicine Biotechnology Health and Medicine Tissue Engineering 223 223 1 07/24/23 20230727 NES 230727 2023 JUL 27 (NewsRx) -- By a News Reporter-Staff News Editor at Blood Weekly -- Researchers detail new data in Biomedical Engineering - Tissue Engineering. Keywords for this news article include: Yantai, People's Republic of China, Asia, Bioengineering, Biomedical Engineering, Biomedicine, Biotechnology, Health and Medicine, Tissue Engineering, Ludong University. People's Republic of China, Asia, Bioengineering, Biomedical Engineering, Biomedicine, Biotechnology, Health and Medicine, Tissue Engineering, Yantai. [Extracted from the article]

The news correspondents obtained a quote from the research from Wenzhou Medical University, "The iminoboronate ester is sensitive to the acidic and oxidative biofilm microenvironment, liberating nitric oxide and Cip that can synergistically eradicate bacterial biofilms. Keywords: Zhejiang; People's Republic of China; Asia; Antimicrobials; Bacterial Infections and Mycoses; Chemicals; Drugs and Therapies; Health and Medicine; Nitric Oxide EN Zhejiang People's Republic of China Asia Antimicrobials Bacterial Infections and Mycoses Chemicals Drugs and Therapies Health and Medicine Nitric Oxide 1505 1505 1 04/03/23 20230407 NES 230407 2023 APR 7 (NewsRx) -- By a News Reporter-Staff News Editor at Drug Week -- Data detailed on Bacterial Infections and Mycoses have been presented. [Extracted from the article]

Drugs and Therapies - Drug Delivery Systems Investigators publish new report on drug delivery systems. For more information on this research see: Stimuli-Responsive TriblockTerpolymer Conversion into Multi-Stimuli-Responsive Micelles withDynamic Covalent Bonds for Drug Delivery through a Quick andControllable Post-Polymerization Reaction. [Extracted from the article]

Synthesis-property relation is fundamental to materials science, but many aspects of the relation are not well understood for many materials. Impetus for this paper comes from our recent appreciation for the distinct roles of entanglements and crosslinks in a polymer network. Here we study the synthesis-property relation of polyacrylamide hydrogels prepared by free radical polymerization. Some of the as-prepared hydrogels are further submerged in water to swell either to equilibrium or to a certain polymer content. The synthesis parameters include the composition of a precursor, as well as the polymer content of a hydrogel. Series of hydrogels are prepared along several paths in the space of synthesis parameters. For each hydrogel, the stress-stretch curve is measured, giving four properties: modulus, strength, stretchability, and work of fracture. We interpret the experimentally measured synthesis-property relation in terms of entropic polymer networks of covalent bonds. When the precursor has a low crosslinker-to-monomer molar ratio, the resulting polymer network has on average long polymer segments. When the precursor has a low water-to-monomer molar ratio, the resulting polymer network has on average many entanglements per polymer segment. We show that crosslinks lower strength, but entanglements do not. By contrast, both crosslinks and entanglements increase modulus. A network of highly entangled long polymer segments exhibits high swell resistance, modulus, and strength. [ABSTRACT FROM AUTHOR]

Dynamic covalent network (or covalent adaptable network) polymers can rearrange their macromolecular chain network by bond exchange reactions (BERs) where an active unit replaces a unit in an existing bond to form a new bond. Such macromolecular events, when they occur in large amounts, can attribute to unusual properties that are not seen in conventional covalent network polymers, such as shape reforming and surface welding; the latter further enables the important attributes of material malleability and powder-based reprocessing. In this paper, a multiscale modeling framework is developed to study the surface welding of thermally induced dynamic covalent network polymers. At the macromolecular network level, a lattice model is developed to describe the chain density evolution across the interface and its connection to bulk stress relaxation due to BERs. The chain density evolution rule is then fed into a continuum level interfacial model that takes into account surface roughness and applied pressure to predict the effective elastic modulus and interfacial fracture energy of welded polymers. The model yields particularly accessible results where the moduli and interfacial strength of the welded samples as a function of temperature and pressure can be predicted with four parameters, three of which can be measured directly. The model identifies the dependency of surface welding efficiency on the applied thermal and mechanical fields: the pressure will affect the real contact area under the consideration of surface roughness of dynamic covalent network polymers; the chain density increment on the real contact area of interface is only dependent on the welding time and temperature. The modeling approach shows good agreement with experiments and can be extended to other types of dynamic covalent network polymers using different stimuli for BERs, such as light and moisture etc. [ABSTRACT FROM AUTHOR]

Sanofi-backed Matchpoint is launching with $70 million in series A funds to finance its covalent chemistry-focused platform. [ABSTRACT FROM AUTHOR]

Unlike traditional thermosets, vitrimers with dynamic covalent bonds enable welding through thermally activated bond exchange reactions. The welding strength of such vitrimers highly depends on the chain diffusion across the interface. However, the understanding of diffusion-triggered welding of vitrimers still remains elusive. Herein, we study the welding of vitrimers through a combination of theory and experiment. We disentangle the welding of vitrimer into three processes: pressure-assisted surface contact, thermally induced chain diffusion across the interface, and chain association due to bond exchange reactions. Then we propose a framework for modeling the welding of vitrimers emphasizing the interfacial chain diffusion and interaction of the three processes. The framework identifies the associated chain ratio as a key intermediate parameter for scaling the welding efficiency and conditions. Based on this, a nonlinear eight-chain model is derived that accounts for bond exchange reactions in the welded vitrimer for the subsequent stretching. As such, this model captures the effects of chain diffusion, welding pressure, and welding time on the tensile strength of welded vitrimers. The present model agrees well with experiments for hard glassy and soft rubbery vitrimers. We also formulate a contour diagram in the welding pressure- time space. This work will guide the welding of vitrimers, as well as contribute to the mechanics of welding. [ABSTRACT FROM AUTHOR]

The article focuses on the research related to the use of DNA for data storage and processing using DNA computing technology conducted by scientist Leonard Adleman of the University of Southern California in the 1990s. Topics discussed include designing of transport networks without the need for programming by slime mould Physarum polycephalum, the chemistry of carbon containing compounds including DNA in which atoms are bonded with covalent bonds and use of computing for medical diagnostics. INSETS: COMPUTING WITH SLIME MOULD;UNDERSTANDING BASE PAIRS;DNA'TELEPORTATION'.

Abstract: Network polymers with thermally reversible linkages include functionalities that continuously break and form covalent bonds. These processes dynamically change the network connectivity, which produces three distinct behaviors compared with conventional thermosetting polymers (in which the network connectivity is static): permanent shape evolution in the rubbery state; dependence of the number density of chains and associated thermal and mechanical properties on temperature and chemical composition; and a gel-point transition temperature above which the connectivity of the network falls below the percolation threshold, and the material response changes from a solid to liquid. This last property allows such materials to be non-mechanically removed, which is an attractive material capability for encapsulation in specialized electronics packaging applications wherein system maintenance is required. Given their complex, multi-physics behavior, appropriate simulation tools are needed to aid in their use. To meet this need, a thermodynamically consistent constitutive model is developed that accounts for the thermal–chemical–mechanical behavior of such materials. This model includes a representation for the permanent shape evolution that accompanies the dynamic network connectivity as well as non-equilibrium viscoelastic behavior to represent the material's glassy response. Analytic solutions in the rubbery state are derived to show the effects of competing time scales in the material, and the model is calibrated and validated against experimental data published in the literature. Finally, simple encapsulation scenarios are examined that demonstrate a substantial difference in behavior between conventional polymer networks and those with thermally reversible linkages under thermal–mechanical cycling. [Copyright &y& Elsevier]

Abstract: Mechanically induced chemical reactivity is a promising means for designing self-sensing and autonomous materials. Force sensitive chemical groups called mechanophores can be covalently linked into polymers in order to trigger specific chemical reactions upon mechanical loading. A model framework is developed to describe the response of these mechanophores to mechanical loading within an elastomeric matrix. A multiscale modeling scheme is used to couple mechanophore kinetics with rubbery elasticity. In particular, transition state theory for the population of mechanophores is modified to account for the stress-induced changes in kinetics within the solid state. The model is specified to the case of spiropyran covalently linked into a polymethacrylate (PMA) backbone. This optically trackable mechanophore (optically active through absorption and fluorescence when triggered) allows the model to be assessed in comparison to observed experimental behavior. The activation predicted by the ideal viscous elastomer model is reasonable, but consistently occurs at a larger strain than in the experiments. The glassy portion of the PMA response accounts for part of the difference in the onset of activation between experiments and the ideal elastomer model. The glassy stress response is therefore included as an additional empirically determined driving force for activation in the model. The remainder of the discrepancy between the experimental and simulation results is attributed to force inhomogeneity within the rubbery network, highlighting that the mechanophore response is correlated with local force history rather than with macroscopic stress. [Copyright &y& Elsevier]

Terremoto Biosciences will use $75 million in series A funding to broaden the covalent drug alphabet available to treat complex diseases. [ABSTRACT FROM AUTHOR]

Abstract: We develop a thermodynamics and mechanics theory for polymers that when irradiated with light, undergo photochemical reactions that alter their macromolecular structure, e.g., by bond breaking and/or reformation, and in turn affect their mechanical and physical behavior. This emerging class of highly-engineered active materials shows great promise for myriad applications and is a subset of a broader class of polymers with covalent bonds that can be dynamically tuned with various environmental stimuli. We formulate a general thermodynamic and kinetic framework to model the complex photochemical–thermal–mechanical coupling in these materials. Our theory considers the behavior of a polymer that is subjected to the combination of mechanical and thermal loading while simultaneously irradiated by light with multiple frequency components and directions. We introduce an approach to model the photochemical reactions that can change the network topology, resulting chemical species transport, heat conduction and finite deformation. We describe the interaction of the material with light via a radiometric description and show how it can be linked to a full electromagnetic treatment when appropriate and if desired. Our approach is sufficiently general to permit the modeling of various materials that operate via different photochemical reaction mechanisms. After formulating the general theory, we specialize it to a polymer that when irradiated with light undergoes a series of photochemical reactions that cause chain scission and reformation which continuously rearrange the polymer network into a stress-free configuration. Based on the operant physical mechanisms we develop a constitutive model using a polymer chain decomposition and evolution approach to track the molecular structure changes during simultaneous irradiation and mechanical loading. In the special case of isothermal conditions with monochromatic and unidirectional irradiation, we recover a previous model based on intuitive ad-hoc assumptions and thus put it on strong thermodynamic footing. Finally we use our model to simulate the behavior of a polymer that is biaxially stretched and then irradiated with light from one side. We simulate the process and emphasize the spontaneous bending that occurs due to inhomogeneous photoinduced stress relaxation. From our theory, we obtain an analytical expression of a characteristic time for photo-induced stress relaxation in terms of the dominating system parameters. [Copyright &y& Elsevier]

Abstract: Different from previous molecular dynamics (MD) simulation with pair potentials and many-body potentials, an efficient and highly scalable algorithm for GPU-accelerated MD simulation of solid covalent crystals is described in detail in this paper using sophisticated many-body potentials, such as Tersoff potentials for silicon crystals. The algorithm has effectively taken advantage of the reordering and sorting of atoms and the hierarchical memory of a GPU. The final results indicate that, about 30.5% of the peak performance of a single GPU can be achieved with a speedup of about 650 over a contemporary CPU core, and more than 15 million atoms can be processed by a single GPU with a speed of around 2 ns/day. Furthermore, the proposed algorithm is scalable and transferable, which can be applied to other many-body interactions and related large-scale parallel computation. [Copyright &y& Elsevier]

Abstract: Mesoscale simulation techniques are becoming increasingly important due to the interest in complex mechanical problems involving nanomaterials. We propose applying the established macroscopic modeling concept of distinct spherical elements down to the mesoscale to simulate mechanical behavior of carbon nanotube systems. Starting from a microscopic description, the important interactions are encapsulated into two types of contact models that act simultaneously. Each individual nanotube is coarse-grained into a chain of spherical elements interacting by parallel-bonded contacts, representing the short-ranged covalent bonding. An anisotropic van der Waals model with aligning moments acts at the contact between elements located in different tubes to represent the long-ranged interactions. The promising potential of the proposed methodology to model large scale carbon nanotube assemblies is illustrated with several examples, including self-folding of individual nanotubes, mechanical testing of nanotube ropes, self-assembly of a high-porosity nanotube paper, and mechanical testing of a low-porosity nanotube paper. [Copyright &y& Elsevier]

The article presents information on the creation of a vaccine that is more potent than the traditional vaccines. It states that the glycoconjugate vaccines prototype is 100 times more effective than traditional glycoconjugate vaccines. It further informs that the glyconjugate vaccines are comprised of covalently bound carbohydrates and protein molecules.

The article informs that according to a study published in the journal "Science" and conducted by Andrei Tokmakoff of the University of Chicago, strong variety of hydrogen bond is hybrid, as it involves shared electrons, blurring the distinction between hydrogen and covalent bonds. It mentions that atoms connected by covalent bonds are considered part of a single molecule, while those connected by hydrogen bonds can remain separate entities.

Natural and synthetic rubbers (networks of polymer chains connected by irreversible chemical cross-links) cannot be repaired after damage, while discarded rubbers cannot be economically recycled and reprocessed. To avoid this shortcoming, a number of elastomers with dynamic covalent bonds have recently been synthesized that demonstrate recyclability, malleability and capability of autonomous self-healing due to thermally triggered bond-exchange reactions. A constitutive model is developed for the thermo-viscoelastic and thermo-viscoplastic responses of elastomers whose chains are bridged by adaptive bonds with the associative mechanism of rearrangement. Material parameters in the governing equations are determined by fitting observations in tensile tests, cyclic tests, relaxation tests and creep tests in a wide range of temperatures on covalently cross-linked rubber, thermoplastic elastomer, several elastomers and elastomer nanocomposites with dynamic covalent bonds, and epoxy vitrimers. Characteristic features are discussed of the thermo-mechanical behavior of elastomers with dynamic bonds and structure–property relations are established for these materials. [ABSTRACT FROM AUTHOR]

The article offers information on a report by a team of chemists from the University of Manchester which discusses a new method for the measurement of covalency in actinide compounds, which is the extent to which electrons are shared between an actinide metal ion and a coordinated ligand atom.

The article presents a research on covalent organic frameworks (COFs) which creates a molecular system that absorbs carbon dioxide and selectively reduces it to carbon monoxide. It present views of chemists Christopher Chang on use of COFs for carbon capture and separation and Omar Yaghi on reticular chemistry technique for molecular backbone of COFs. It also mentions use of COFs to form reduced carbon products such as methanol and carbon-carbon bond-coupled product ethylene.

The article discusses research on how carbon connects to other atoms. It references a study by Dean Tantillo et al and published in the January 2, 2017 issue of "Angewandte Chemie." Topics covered include the finding that carbon atom bonds to six other carbon atoms, an exception to carbon's textbook four-bond limit, the study's discovery about a molecule called hexamethylbenze, and other exceptions to carbon's four-bond limit identified by the study.