Chemical Modification Research Articles

Reading m6A marks in mRNA: A potent mechanism of gene regulation in plants.

Modifications to RNA have recently been recognized as a pivotal regulator of gene expression in living organisms. More than 170 chemical modifications have been identified in RNAs, with N6-methyladenosine (m6A) being the most abundant modification in eukaryotic mRNAs. The addition and removal of m6A marks are catalyzed by methyltransferases (referred to as "writers") and demethylases (referred to as "erasers"), respectively. In addition, the m6A marks in mRNAs are recognized and interpreted by m6A-binding proteins (referred to as "readers"), which regulate the fate of mRNAs, including stability, splicing, transport, and translation. Therefore, exploring the mechanism underlying the m6A reader-mediated modulation of RNA metabolism is essential for a much deeper understanding of the epigenetic role of RNA modification in plants. Recent discoveries have improved our understanding of the functions of m6A readers in plant growth and development, stress response, and disease resistance. This review highlights the latest developments in m6A reader research, emphasizing the diverse RNA-binding domains crucial for m6A reader function and the biological and cellular roles of m6A readers in the plant response to developmental and environmental signals. Moreover, we propose and discuss the potential future research directions and challenges in identifying novel m6A readers and elucidating the cellular and mechanistic role of m6A readers in plants.

PDCdb: the biological activity and pharmaceutical information of peptide-drug conjugate (PDC).

Peptide-drug conjugates (PDCs) have emerged as a promising class of targeted therapeutics with substantial pharmaceutical advantages and market potentials, which is a combination of a peptide (selective to the disease-relevant target), a linker (stable in circulation but cleavable at target site)and a cytotoxic/radioactive drug (efficacious/traceable for disease). Among existing PDCs, those based on radiopharmaceuticals (a.k.a. radioactive drugs) are valued due to their accurate imaging and targeted destruction of disease sites. It's demanded to accumulate the biological activity and pharmaceutical information of PDCs. Herein, a database PDCdb was thus constructed to systematically describe these valuable data. Particularly, biological activities for 2036 PDCs were retrieved from literatures, which resulted in 1684, 613and 2753 activity data generated based on clinical trial, animal modeland cell line, respectively. Furthermore, the pharmaceutical information for all 2036 PDCs was collected, which gave the diverse data of (a) ADME property, plasma half-lifeand administration approach of a PDC and (b) chemical modification, primary target, mode of action, conjugating feature of the constituent peptide/linker/drug. In sum, PDCdb systematically provided the biological activities and pharmaceutical information for the most comprehensive list of PDCs among the available databases, which was expected to attract broad interest from related communities and could be freely accessible at: https://idrblab.org/PDCdb/.

Recent Advances in Self-Assembling Peptide-Based Nanomaterials for Enhanced Photodynamic Therapy.

Self-assembling peptide-based materials with ordered nanostructures possess advantages such as good biocompatibility and biodegradability, superior controllability, and ease of chemical modification. Through covalent conjugation or non-covalent encapsulation, photosensitizers (PSs) can be carried by self-assembling peptide-based nanomaterials for targeted delivery towards tumor tissues. This improves the stability, solubility, and tumor accumulation of PSs, as well as reduces their dark toxicity. More importantly, these nanomaterials can be tailored with responsiveness to tumor microenvironment, which enables smart release of PSs for precise and enhanced photodynamic therapy (PDT). In this review, the self-assembly of peptide from the perspective of driving forces is first described, and various self-assembling peptide materials with zero to 3D nanostructures are subsequently highlighted for PDT of cancers in recent years. Finally, an outlook in this field is provided to motivate fabrication of advanced PDT nanomaterials.

Modification approaches of walnut proteins to improve their structural and functional properties: A review

Walnut protein has a high gluten content and compact structure, which limits its water solubility and affects its applications. Therefore, improving the sustainability of walnut proteins is an urgent issue that must be addressed. Physical modification can directly alter the structure of walnut proteins, leading to enhanced functional properties. Chemical modifications typically involve the introduction of exogenous substances that react with walnut proteins to obtain novel products with improved processing attributes. As a highly specific modification technique, biomodification uses enzymes or microorganisms to break down walnut proteins into small peptide molecules or cross-link them to form soluble polymers, thereby enhancing their functional properties and bioactivity. This review presents various methods for modifying walnut proteins and their effects on the structure and functional properties of walnut proteins. The challenges associated with the application and development of these unique technologies are also discussed.

Acetylation, ADP-ribosylation and methylation of malate dehydrogenase.

Metabolism within an organism is regulated by various processes, including post-translational modifications (PTMs). These types of chemical modifications alter the molecular, biochemical, and cellular properties of proteins and allow the organism to respond quickly to different environments, energy states, and stresses. Malate dehydrogenase (MDH) is a metabolic enzyme that is conserved in all domains of life and is extensively modified post-translationally. Due to the central role of MDH, its modification can alter metabolic flux, including the Krebs cycle, glycolysis, and lipid and amino acid metabolism. Despite the importance of both MDH and its extensively post-translationally modified landscape, comprehensive characterization of MDH PTMs, and their effects on MDH structure, function, and metabolic flux remains underexplored. Here, we review three types of MDH PTMs - acetylation, ADP-ribosylation, and methylation - and explore what is known in the literature and how these PTMs potentially affect the 3D structure, enzymatic activity, and interactome of MDH. Finally, we briefly discuss the potential involvement of PTMs in the dynamics of metabolons that include MDH.

Thermal Compatibility of New ACEI Derivatives with Popular Excipients Used to Produce Solid Pharmaceutical Formulations.

Background/Objectives: Increasing drugs' stability and adequately protecting them against degradation will ensure a decrease in their price and broader availability of pharmaceutical substances. This is of great importance, especially for drugs used to treat the most common diseases in the population, such as hypertension. The study examined two newly synthesized substances from the angiotensin I-converting enzyme inhibitor (ACEI) group as potential drugs. ACEIs are among the leading drugs used in the treatment of hypertension in the world. The chemical modifications of the tested substances applied concerned the places most susceptible to degradation. The presented work analyzed the compatibility of new derivatives with selected excipients used in pharmacy. Methods: Thermogravimetric (TGA) and differential thermal analyses (c-DTA) were used as the main methods. In addition, non-thermal methods such as colorimetry analysis, Fourier-transform infrared (FTIR) and UV spectroscopy were used. Results: Based on the conducted studies, it can be concluded that the incompatibility of IND-1 with glucose anhydrous and lactose monohydrate occurs only when the mixture is stored at higher temperatures. For the remaining IND-1 and IND-2 mixtures with excipients, compatibility was demonstrated. Conclusions: The obtained results confirmed the usefulness of the applied thermal analyses (TGA and c-DTA) for assessing the compatibility of the tested potential drugs with excipients. However, in the case of incompatibility reactions of substances occurring under the influence of elevated temperatures, such as the Maillard reaction, it is necessary to use non-thermal methods to obtain the right result.

Influence of polypropylene fibers on the tensile mechanical properties of calcium silicate hydrate: molecular simulation.

This research assesses the influence of polypropylene (PP) fibers, both homopolymer and hydroxylated (PPOH), on the tensile properties of calcium silicate hydrate (C-S-H) composites through molecular dynamics (MD) simulations. Our models explore C-S-H matrices integrated with PP and PPOH fibers at varying polymerization degrees. The results demonstrate that both PP and PPOH fibers significantly influence the tensile strength and Young's modulus of the composites. Notably, PPOH fibers contribute to more substantial mechanical enhancements than PP, attributed to the increased polarity and enhanced intermolecular interactions from the hydroxyl groups. The study reveals a nonlinear relationship between polymer additive content and mechanical performance, with optimal properties at a polymerization degree of 20. Additionally, stress-strain analysis indicates that PPOH composites exhibit superior ductility and fracture energy, particularly at polymerization degrees of 20, showing enhanced ultimate strain and fracture energy by up to 9.6% and 13.9%, respectively, compared to PP counterparts. These results highlight the crucial role of tailored polymer additive composition and chemical modifications in maximizing the mechanical efficacy of C-S-H-based materials, enhancing their durability and structural performance. All MD simulations were conducted using LAMMPS. The models employed a combination of Clayff and Cvff force fields. During the entire tensile simulation, the system was configured under the NPT ensemble at 300K.

Novel Lewis Acid‐Base Interactions in Polymer‐Derived Sodium‐Doped Amorphous Si−B−N Ceramic: Towards Main‐Group‐Mediated Hydrogen Activation

AbstractInterest is growing in transition metal‐free compounds for small molecule activation and catalysis. We discuss the opportunities arising from synthesizing sodium‐doped amorphous silicon‐boron‐nitride (Na‐doped a‐SiBN). Na+ cations and 3‐fold coordinated BIII moieties were incorporated into an amorphous silicon nitride network via chemical modification of a polysilazane followed by pyrolysis in ammonia (NH3) at 1000 °C. Emphasis is placed on the mechanisms of hydrogen (H2) activation within Na‐doped a‐SiBN structure. This material design approach allows the homogeneous distribution of Na+ and BIII moieties surrounded by SiN4 units contributing to the transformation of the BIII moieties into 4‐fold coordinated geometry upon encountering H2, potentially serving as frustrated Lewis acid (FLA) sites. Exposure to H2 induced formation of frustrated Lewis base (FLB) N−= sites with Na+ as a charge‐compensating cation, resulting in the in situ formation of a frustrated Lewis pair (FLP) motif (≡BFLA⋅⋅⋅Hδ−⋅⋅⋅Hδ+⋅⋅⋅:N−(Na+)=). Reversible H2 adsorption‐desorption behavior with high activation energy for H2 desorption (124 kJ mol−1) suggested the H2 chemisorption on Na‐doped a‐SiBN. These findings highlight a future landscape full of possibilities within our reach, where we anticipate main‐group‐mediated small molecule activation will have an important impact on the design of more efficient catalytic processes and the discovery of new catalytic transformations.

Unlocking the potential of borophene nanoribbons for efficient hydrogen storage

This research explores the structural, electronic, optical, and hydrogen storage properties of borophene nanoribbons (BNRs) with armchair (ANR-B-H) and zigzag (ZNR B-H) edges. Computational simulations optimized these structures, revealing that 7ZNR-B-H has a superior binding energy. Chemical modifications, such as fluorine passivation and functionalization, influenced bond parameters and quantum properties. Bilayer BNRs showed increased stability and enhanced electrical conductivity. Our study demonstrated promising hydrogen storage capabilities, with passivated and functionalized BNRs achieving suitable adsorption energies and a significant gravimetric storage capacity of 20.32 wt%, exceeding DOE standards. NH2 functionalization notably improved adsorption energy, enhancing potential for efficient hydrogen storage. Changes in absorption spectra post-H2 adsorption further highlight BNRs’ potential for hydrogen storage applications. These findings provide valuable insights into BNRs, paving the way for their use in electronic devices and hydrogen storage systems.

Development of composite ultrafiltration membrane from fly ash microspheres and alumina nanofibers for efficient dye removal from aqueous solutions

In this work, a novel type of ultrafiltration ceramic membranes with the support based on fine fly ash microspheres and selective layer based on the alumina nanofibers with an aluminosilicate binder is proposed. The average pore sizes of the support and selective layer are 0.46 μm and 29 nm, respectively. The membrane is characterized by the compressive strength of 96 MPa and water permeability of 207 L m−2 h−1 bar−1. It is shown that the binder provides structural stability of selective layer and adhesion to the support. With increasing the binder content, the water permeability increases, reaches maximum, and then slightly decreases. The developed membranes are used for ultrafiltration of Blue Dextran dyes aqueous solutions with molecular weights of 70 kDa and 500 kDa and concentrations of 50 and 100 mg/L. The dyes rejection varies in the range 97–99 %, while the permeate flux is 100–140 L m−2 h−1 at the transmembrane pressure of 4 bars. The dye retention occurs via adsorption at the initial stage, which leads to the narrowing of pore size. Further, the dye filtration proceeds mainly due to size effects. The proposed membranes can be employed for dye removal from wastewater, and also allow chemical modification by carbon coating to be employed in electrochemically assisted ultrafiltration. The developed methodology promotes the recycling of thermal energy waste and introduces novel approaches to combine waste and synthesized raw materials in the production of low-cost ceramic membranes.

Advancing piezoelectricity and excellent thermal stability: -textured 0.75BF–0.25BT lead-free ceramics for high temperature applications

There is an urgent need for piezoelectric materials possessing both high piezoelectric properties and good thermal stability to facilitate the advancement of high temperature piezoelectric devices. However, conventional strategy for enhancing piezoelectricity via chemical modifications often comes at the cost of thermal stability due to a drop in Curie temperatures. In this study, we achieved remarkable results in <001>-oriented 0.75BiFeO3–0.25BaTiO3 (0.75BF–0.25BT) lead-free textured ceramics. These textured ceramics exhibit a high Curie temperatures Tc of 552 °C, large piezoelectric coefficients d33 of 265 pC/N, and exceptional piezoelectric thermal stability, with minimal variation of 8% across temperature from 25 °C to 300 °C. Compared to randomly oriented ceramics, the piezoelectric coefficient is about 2.5 times higher, marking it as one of the highest reported value for ceramics with Tc near 550 °C. The enhanced piezoelectric properties can be ascribed to improvements in both intrinsic lattice distortions and extrinsic non-180o domain motions, while the excellent piezoelectric thermal stability is attributed to the stable domain texture. These superior properties of the studied textured 0.75BF–0.25BT ceramics position them as competitive lead-free candidates for high-temperature piezoelectric applications.

Superhydrophobic carbon fiber composite coatings based on TC4 titanium alloy for improving corrosion resistance

Seawater corrosion poses significant challenges to marine industrial equipment, leading to a reduced lifespan and potential safety hazards. To enhance the corrosion resistance and reliability of titanium alloys in marine environments, a superhydrophobic TiO₂ nanotube-carbon fiber composite coating (SCF-TAD20) was developed through anodic oxidation, spraying, and chemical modification. SCF-TAD20 achieves a contact angle of 153°, which facilitates excellent corrosion protection due to its unique micro-nano structure, gas barrier properties, and chemical resistance. Electrochemical tests demonstrate that SCF-TAD20 increases the corrosion potential from -0.482 V to 0.0612 V and reduces the corrosion current density from 377.8 × 10-8 A/cm2 to 0.615 × 10-8 A/cm2, a four-order decrease. Its charge transfer resistance (∼8.81E6 Ω·cm2) is significantly higher than that of the substrate (∼3.03E5 Ω·cm2). The coating also performs well in seawater with varying pH levels, showing the lowest corrosion current density and a significant increase in resistive arc radius. This research presents a novel approach to enhancing TC4 titanium alloys for marine applications.

Physico-mechanical characterization and DFT studies of benzoyl peroxide treated water hyacinth reinforced polypropylene composites

The use of eco-friendly natural fiber-reinforced polymer composites is rapidly expanding across diverse sectors. The rapid spread of water hyacinth disrupts aquatic ecosystems by modifying the pH of water and salinity in Bangladesh. This work investigated on the impact of incorporating both untreated and chemically treated water hyacinth fibers into polypropylene (PP). Untreated water hyacinth (UWH) powder was treated with an alkaline solution, producing mercerized water hyacinth (MWH). MWH was further oxidized to yield oxidized water hyacinth (OWH). Analysis of attenuated total reflection-fourier transform infrared (ATR-FTIR) spectra of UWH, MWH and OWH confirmed cellulose modification. The UWH and OWH were taken in varying contents (1, 2.5, 5, 7.5, and 10 wt%) and added to PP to make UWH-PP and OWH-PP composites using compression molding technique. The 1% fiber content OWH-PP composites exhibited enhanced tensile strength, elongation, and impact strength compared to UWH-PP composites. Enhanced mechanical properties in OWH-PP composites suggested that benzoyl peroxide treatment improves interfacial adhesion. Morphological analysis of the OWH-PP composite showed better interfacial bonding between water hyacinth and PP than that of the UWH-PP composite. Thermogravimetric analysis (TGA) depicted the thermal stability of the UWH-PP and OWH-PP composites. The chemical reaction of cellulose monomer was further studied with DFT/B3LYP level of theory using two different basis sets 6-31+G(d, p) and cc-pVTZ. The calculated vibrational spectra of the untreated, mercerized and oxidized cellulose monomer agree well with the ATR-FTIR spectra, confirming chemical modification. DFT calculations of thermodynamic properties revealed the feasibility of the reactions. Electronic property (NBO charge) indicated charge transfer and structural changes during chemical modification.

Chemical analysis and performance evaluation of ClearCorrect® aligners as received and after intraoral use: Implications for durability, aesthetics, and patient safety

BackgroundOrthodontic treatment with transparent aligners is popular with patients. Any alteration of the plastic material, as subjected to the oral environment, could influence the treatment's durability, the aligner's aesthetic appearance, and the patient's safety. PurposeThis study concerns the physicochemical properties of ClearCorrect® aligners before and after intraoral use, focusing on transparency, surface topography, leachable, polymer glass transition temperature, and viscoelastic properties. MethodsAligners were collected after two weeks of intraoral use. Unused samples were obtained from the manufacturers. Transparency was measured by UV–visible spectroscopy. Chemical modifications were studied using infrared and Raman spectroscopies. Thermal degradation, glass transition (Tg), and storage modulus (E') were characterized by thermal analysis (DSC, TGA, DMA). Surface morphology and roughness were studied thanks to SEM and AFM. Aligners were immersed in water-based solutions to identify and quantify organic leachable by HPLC chromatography and trace elements by atomic absorption spectroscopy. ResultsClearCorrect® aligners have a three-layer structure (outer PETG/inner PU layers). Slight chemical alterations occurred after aging. There was also no significant evolution in Tg and thermal degradation temperatures and only a minimal evolution of E'. Surface and transparency alterations occurred. A difference in organic compound and trace element release levels between new and used aligners was evidenced, suggesting an intraoral release during use. SignificanceIntra-oral aging mainly impacts the aligner transparency and surface. The leachable study suggests significant ingestion of organic and non-organic compounds by the patient: investigations are needed to assess the impact of the long-term use of trays on patient health.

The Mechanisms of miRNAs on Target Regulation and their Recent Advances in Atherosclerosis.

miRNAs are crucial regulators in a variety of physiological and pathological processes, while their regulation mechanisms were usually described as negatively regulating gene expression by targeting the 3'-untranslated region(3'-UTR) of target gene miRNAs through seed sequence in tremendous studies. However, recent evidence indicated the existence of non-canonical mechanisms mediated by binding other molecules besides mRNAs. Additionally, accumulating evidence showed that functions of intracellular and intercellular miRNAs exhibited spatiotemporal patterns. Considering that detailed knowledge of the miRNA regulating mechanism is essential for understanding the roles and further clinical applications associated with their dysfunction and dysregulation, which is complicated and not fully clarified. Based on that, we summarized the recently reported regulation mechanisms of miRNAs, including recognitions, patterns of actions, and chemical modifications. And we also highlight the novel findings of miRNAs in atherosclerosis progression researches to provide new insights for non-coding RNA-based therapy in intractable diseases.

Surface-engineered caterpillar-like silica nanocomposites for enhanced interparticle friction and interlock in shear thickening suspension

This study presents a novel method for fabricating surface-engineered caterpillar-like silica nanocomposites by combining rod-like nanorods with spherical nanoparticles to control aspect ratios and surface functionalization. This unique design facilitates functional assembly at the nanoscale. Additionally, we developed an innovative composite by encapsulating polyurethane elastomers within shear thickening fluid (STF)-impregnated Kevlar, significantly enhancing the flexibility and durability of the resulting STF/Kevlar/PU composite. Microstructural and chemical modifications were characterized, and detailed rheological analysis revealed a 165 % increase in viscosity and a substantial rise in storage modulus from 91.56 to 18,640 Pa, indicating improved surface morphology and roughness. These enhancements promoted stronger interparticle friction and rotational motion during flow. Impact resistance tests further demonstrated a 314 % increase in peak impact force, driven by frictional interactions between the dispersed caterpillar-like particles. The results confirmed that surface roughness and adhesive forces play a critical role in activating stress-dependent frictional contacts, a key mechanism behind the improved performance. These findings highlight the potential of these composites for mitigating penetration injuries and offer precise control over the shear-thickening transition in engineering applications, making them promising candidates for lightweight protective materials.

Carboxylic Group Functionalized Carbon Quantum Dots inhibit Hen Egg White Lysozyme Amyloidogenesis, leading to the Formation of Spherical Aggregates with Reduced Toxicity and ROS Generation.

Proteinopathies are a group of diseases where the protein structure has been altered. These alterations are linked to the production of amyloids, which are persistent, organized clumps of protein molecules through inter-molecular interactions. Several disorders, including Alzheimer's and Parkinson's, have been related to the presence of amyloids. Highly ordered beta sheets or beta folds are characteristic of amyloids; these structures can further self- assemble into stable fibrils. Protein aggregation is caused by a wide variety of environmental and experimental factors, including mutations, high pH, high temperature, and chemical modification. Despite several efforts, a cure for amyloidosis has yet to be found. Due to its advantageous semi-conducting characteristics, unique optical features, high surface area-to-volume ratio, biocompatibility, etc., carbon quantum dots (CQDs) have lately emerged as key instruments for a wide range of biomedical applications. To this end, we have investigated the effect of CQDs with a carboxyl group on their surface (CQD-CA) on the in vitro amyloidogenesis of hen egg white lysozyme (HEWL). By generating a stable compound that is resistant to fibrillation, our findings show that CQD-CA can suppress amyloid and disaggregate HEWL. In addition, CQD-CA caused the creation of non-toxic spherical aggregates, which generated much less reactive oxygen species (ROS). Overall, our results show that more research into amyloidosis treatments, including surface functionalized CQDs, is warranted.

Uncovering the Potential of Chalcone-Sulfonamide Hybrids: A Systematic Review on Their Anticancer Activity and Mechanisms of Action.

Cancer is the second leading cause of death worldwide and is considered a major public health problem. Despite the significant advances in cancer research, the conventional cancer treatment approaches often lead to serious side effects that affect the quality of life of cancer patients. Thus, searching for new alternatives for cancer treatment is crucial to minimize these problems. Chalcone-sulfonamide hybrids display a range of biological activities and have been widely investigated for their anticancer potential, being considered promising molecules for cancer treatment. This systematic review aimed to summarize the information available in the literature about the anticancer potential of chalcones-sulfonamides in vitro and in vivo and their mechanisms of action. Our analysis demonstrated that chalcones-sulfonamides have relevant cytotoxic potential against different cancer cell lines in vitro, especially against the human colorectal carcinoma cell line HCT-116. These molecules have also reduced tumor growth in vivo. Some chalcones-sulfonamides had improved cytotoxicity after chemical modification and could become more selective or even more potent than reference chemotherapeutics. The mechanisms underlying these effects demonstrated that chalcones-sulfonamides may lead to cell death by different pathways, predominantly via apoptosis or necroptosis. This review may encourage researchers to advance studies with chalcones-sulfonamides, especially to elucidate their mechanisms of action, contributing to the development of new alternatives to cancer treatment.

Modification of chemical vapor-phase deposition and coking resistance over HZSM-5 catalysts for toluene disproportionation

Abstract To achieve higher catalytic activity of toluene disproportionation and improve the p-xylene selectivity and stability of coking resistance on HZSM-5 catalysts, tetrabutyl titanate, ethyl orthosilicate and diethyl phosphite were used for chemical gas-phase deposition modification on HZSM-5 catalysts. The properties of acid sites on catalysts were characterized by infrared spectroscopy (IR) and temperature-programmed desorption of pyridine (TPD), respectively. The experimental results showed that the type of acid sites and density of weaker acid sites over HZSM-5 zeolites deposited by oxides containing Ti, Si and P in chemical vapor coating did not change while the density of stronger acid sites decreased, in which acid intensity on HZSM-5 zeolite deposited by oxides containing P enhanced obviously. Using HZSM-5 zeolites modified as catalysts of toluene disproportionation, HZSM-5 catalysts deposited by oxides containing Si and P can greatly improve both catalytic activity and coking resistance on catalysts.

Unlocking the potential of titanium and its alloys: A mini-review on innovative surface modification techniques

Titanium and its alloys are widely utilized in various fields, such as biomedical and aerospace, and in other industrial applications. However, its surface modification is essential to further enrich its properties to enhance its effectiveness. Researchers across the globe are continuously working on a variety of surface modification methods to enhance the properties of titanium and its alloys. This paper presents a comprehensive review of surface modification methods utilized for titanium and its alloys. Some of the important modification techniques discussed in this paper includes mechanical, chemical, electrochemical, thermal, and physical surface modification methods. This paper also provides insights into surface modification methods in terms of improving corrosion and wear resistance, biocompatibility, and hardness of titanium and its alloys.