Low Reactivity Research Articles

Redox Engineering of Myoglobin by Cofactor Substitution to Enhance Cyclopropanation Reactivity

AbstractDesign of metal cofactor ligands is essential for controlling the reactivity of metalloenzymes. We investigated a carbene transfer reaction catalyzed by myoglobins containing iron porphyrin cofactors with one and two trifluoromethyl groups at peripheral sites (FePorCF3 and FePor(CF3)2, respectively), native heme and iron porphycene (FePc). These four myoglobins show a wide range of Fe(II)/Fe(III) redox potentials in the protein of +147 mV, +87 mV, +42 mV and −198 mV vs. NHE, respectively. Myoglobin reconstituted with FePor(CF3)2 has a more positive potential, which enhances the reactivity of a carbene intermediate with alkenes, and demonstrates superior cyclopropanation of inert alkenes, such as aliphatic and internal alkenes. In contrast, engineered myoglobin reconstituted with FePc has a more negative redox potential, which accelerates the formation of the intermediate, but has low reactivity for inert alkenes. Mechanistic studies indicate that myoglobin with FePor(CF3)2 generates an undetectable active intermediate with a radical character. In contrast, this reaction catalyzed by myoglobin with FePc includes a detectable iron–carbene species with electrophilic character. This finding highlights the importance of redox‐focused design of the iron porphyrinoid cofactor in hemoproteins to tune the reactivity of the carbene transfer reaction.

Mealworm Larvae Frass Exhibits a Plant Biostimulant Effect on Lettuce, Boosting Productivity beyond Just Nutrient Release or Improved Soil Properties

There is a need for alternatives or complements to synthetic fertilizers to enhance agricultural sustainability. Applying organic amendments can play a significant role in this. Insect droppings show high potential, though studies evaluating their agronomic value have only recently begun to emerge. This study compared black soldier fly (Hermetia illucens L.) and mealworm (Tenebrio molitor L.) larvae frass with another organic amendment (Nutrimais) derived from composting forestry, agro-industrial, and domestic waste. The experiment also included ammonium nitrate at two rates [the same as the organic amendments, 50 kg ha–1 nitrogen (N) (FullR), and half that rate (HalfR)] and an unfertilized control. The study spanned two growth cycles of lettuce (Lactuca sativa L.) grown in pots, followed by unfertilized oats (Avena sativa L.) to assess the residual effects of the fertilizing treatments. Mealworm larvae frass mineralized rapidly, with an apparent N recovery of 37.4% over the two lettuce growth cycles, indicating its high availability to soil heterotrophic microorganisms. The average dry matter yield (DMY) of lettuce was the highest among all treatments (12.8 and 9.8 g plant–1 in the first and second lettuce cycles), even compared to the FullR treatment (12.2 and 7.8 g plant–1), though without significant differences. Although mealworm larvae frass exhibited a high mineralization rate, the DMY cannot be attributed solely to N supply, as plants in the FullR treatment showed better N nutritional status. Mealworm larvae frass provided strong evidence of a plant biostimulant effect, not explained by the variables measured in this study. Black soldier fly larvae frass exhibited typical behavior of a moderately reactive organic amendment, while Nutrimais showed low reactivity, with a near-neutral mineralization/immobilization balance. The results suggest mealworm larvae frass is recommended for early maturing vegetable crops, whereas Nutrimais appears more suitable for perennial crops with low short-term nutrient requirements.

Patterns of Formation of Binary Cobalt–Magnesium Oxide Combustion Catalysts of Various Composition

In order to establish the formation patterns of the Co–Mg oxide system, samples with different Co:Mg ratios and heat treatment temperatures were synthesized and studied. A study of the samples confirmed the phase transition of MgxCo2–xO4 spinels into the corresponding solid solutions at 800–900 °C. The similarity of the formation patterns for different compositions is shown. The rocksalt oxide in low-temperature samples is an anion-modified paracrystalline phase that forms a “true” solid solution only upon spinel decomposition. The TPR profiles of the decomposed Co3O4 spinel show surface Co3O4 peaks and a wide peak corresponding to the well-crystallized CoO, while partial Co3O4 TPR up to 380 °C results in dispersed and amorphous CoO. The high-temperature non-stoichiometric samples are poorly reduced, indicating their low oxygen reactivity. Spinel reoxidation after heat treatment to 1100 °C by calcination at 750 °C showed complete regeneration for MgCo2O4–Co3O4 samples and its absence in case of an excess of MgO relative to stoichiometry.

Characterization of recurrent cytomegalovirus reactivations post allogenic stem cell transplantation in a population with high seropositivity

ObjectivesThis study aimed to characterize incidences of CMV reactivations within one year post-allo-SCT and identify risk factors for CMV second reactivation episode in population with high seropositivity where first CMV reactivation episode deemed to be high.MethodsThis retrospective cohort study analyzed data from 359 allo-SCT patients aged 14 and older admitted to a tertiary academic hospital. Data on demographic and clinical factors, CMV serostatus, conditioning regimens, graft-versus-host disease prophylaxis, engraftment time, and CMV reactivations were collected.ResultsFirst and second CMV reactivations occurred in 88.9% and 18.4% of post-allo-SCT patients respectively. Patients were stratified into two groups based on primary disease necessitating allo-SCT, patients with malignant (Group 1) and non-malignant (Group 2) hematological disease. Factors associated with the second reactivation included cord blood as a stem cell source, human leukocyte antigen mismatch, acute graft-versus-host disease, and hematological malignancies. Patients with non-malignant hematological disease displayed better outcomes, including a higher rate of spontaneous clearance of first CMV reactivation (70% versus 49.4%) and lower rates of second CMV reactivation (9.6% versus 31%) than those with malignant hematological disease. The one-year overall survival rate was 87.7% (95.5% in non-malignant hematological disease and 78.13% in malignant hematological disease).ConclusionOur findings are concordant with previous local study in regard to high rate of first CMV reactivation post-allo-SCT. It appears that patients with nonmalignant hematological disease had better outcomes, such as lower second CMV reactivation and higher survival rates compared to patients with malignant hematological disease. Further investigation is needed to identify other factors affecting recurrent CMV reactivations in allo-SCT in patients with malignant hematological disease.

Comparison of Intravitreal Ranibizumab and Laser Photocoagulation in the Treatment of Type I Retinopathy of Prematurity in Malaysia: A One-Year Follow-Up Study.

This study aimed to evaluate the treatment efficacy, anatomical outcomes, and refractive outcomes of laser photocoagulation (LPC) and intravitreal ranibizumab (IVR) in the treatment of type I retinopathy of prematurity (ROP) at one-year follow-up. This is a retrospective study on the treatment of type I ROP and aggressive ROP (A-ROP) using LPC or IVR in three Malaysian hospitals providing pediatric ophthalmology services from January 2019 to December 2021. Information on gestational age, birth weight, ROP zone and stage, and underlying comorbidities was collected. Parameters for evaluating treatment efficacy include the time taken to achieve complete regression, the regression rate, and the reactivation rate. The anatomical and refractive outcomes were evaluated at one year of adjusted age. This study included 92 eyes from 46 infants. Of these, 42 eyes received LPC as the initial treatment, while 50 eyes underwent IVR. A higher percentage of infants with cardiovascular disease were treated with IVR (66.7%) compared to LPC (40%) (p<0.05). However, there were no significant differences in gestational age, birth weight, respiratory distress syndrome, sepsis, or intraventricular hemorrhage between the two treatment groups (p>0.05). Infants treated with LPC had a higher regression rate than those treated with IVR, but they were also significantly more myopic and had worse best-corrected visual acuity (BCVA). Conversely, infants treated with IVR experienced a significantly higher reactivation rate compared to those treated with LPC. Logistic regression analysis showed no significant associations between gestational age, birth weight, plus disease, zone 1 ROP, and the choice of initial treatment with the reactivation of ROP. Both LPC and IVR effectively treat type I ROP in infants, with IVR yielding superior anatomical and refractive outcomes and LPC offering a lower reactivation rate. Understanding individual patient characteristics is crucial for treatment selection.

Direct numerical simulations of pure and partially cracked ammonia/air turbulent premixed jet flames

Ammonia has been identified as a promising fuel to diminish greenhouse gas emission. However, ammonia combustion presents certain challenges including low reactivity and high NO emission. In the present study, three-dimensional direct numerical simulations (DNS) of ammonia/air premixed slot jet flames with varying Karlovitz numbers (Ka) and cracking ratios were performed. Three cases were considered, including two pure ammonia/air flames with different turbulence intensities and one partially cracked ammonia/air flame with high turbulence intensity. The effects of turbulence intensity and partial ammonia cracking on turbulence–flame interactions and NO emission characteristics of the flames were investigated. It was shown that the turbulent flame speed is higher for the flames with high turbulence intensity. In general, the flame displacement speed is negatively correlated with curvature in negative curvature regions, while the correlation is weak in the positive curvature regions for highly turbulent flames. Most flame area is consumed in negatively curved regions and produced in positively curved regions. It was found that the NO mass fraction is higher in the flame with partial ammonia cracking compared to the pure ammonia/air flames. The NO pathway analysis shows that the NH → NO pathway is enhanced, while the NO consumption pathway is suppressed in the partially cracked ammonia/air flame. The NO mass fraction is higher in regions of negative curvature than positive curvature. Interestingly, the NO mass fraction is found to be negatively correlated with the local equivalence ratio, which is consistent in both the DNS and the corresponding laminar premixed flames.

Benign and Selective Amination of Lignins towards Aromatic Biobased Building Blocks with Primary Amines

Lignin is a widely available second‐generation biopolymer and the main potential source of renewable aromatic building blocks. Lignin‐based polyamines offer great potential in applications based on chemical and materials sciences. However, common aminations techniques for lignin usually involve toxic chemicals and generate hindered and low reactivity amines. In this study, we developed two new, simple, and benign 2‐step methodologies for the elaboration of lignin‐based polyamines from different technical lignins (kraft, soda and organosolv) with a selectivity towards reactive primary amines. These methods involve grafting amide groups onto lignin followed by a hydrolysis step. Non‐toxic heterocyclic compounds N‐acetyl‐2‐oxazolidinone and 2‐methyl‐2‐oxazoline were used as amidation agents. Hydrolysis was performed in acetone‐water mixtures. Reactions were studied on model compounds and optimized on lignins. Aminated lignins were fully characterized and primary amines were quantified using quantitative 19F NMR. Our methods generated aminated lignins with low apparent molar masses and high solubility in water and solvents. Nitrogen contents of the products ranged between 2.0 and 3.5 mmol/g with reactive primary amines counts up to 1.7 mmol/g. These soluble and reactive lignin‐based polyamines offer great potential as a replacement for fossil‐based polyamines in e.g., the synthesis of aromatic polymer materials or as potential chelating, antibacterial agents.

Study on removal mechanism of polycrystalline diamond wafer by grinding containing transition metals

Polycrystalline diamond wafers valued for their unique optical properties and thermal conductivity, are optimal for high-technologies applications like optical windows and thermal spreaders. They require a very smooth surface finish, demanding to reach nanometer-level roughness. Their hardness and corrosion resistance, however, make surface grain removal difficult, and large grains can cause stress concentration, which can result in cracking. Traditional CMP faces limitations due to slow oxidizer reactivity and contamination risks. This study exploits the reaction between transition metals and diamond wafers to improve removal rates and grain elimination. Adding Fe, Ti, and Ni reactive abrasives in resin diamond wheels, material removal rate by weighing the weight change and surface roughness was measured using a ZYGO 3D profiler. Fe notably increased removal efficiency and surface quality, indicating that transition metals enhance the transformation of surface grains into amorphous carbon for superior processing.

Expanding anti-venom strategies: Camelid polyclonal antibodies with high capacity to recognize snake venom

Camelid immunoglobulins represent a unique facet of antibody biology, challenging conventional understandings of antibody diversification. IgG2 and IgG3 in particular are composed solely of heavy chains and exhibit a reduced molecular weight (90 kDa); their elongated complementarity determining region (CDR) loops play a pivotal role in their functioning, delving deep into enzyme active sites with precision. Serum therapy stands as the primary venom-specific treatment for snakebite envenomation, harnessing purified antibodies available in diverse forms such as whole IgG, monovalent fragment antibody (Fab), or divalent fragment antibody F (ab')2. This investigation looks into the intricacies of IgGs derived from camelid serum previously immunized with crotamine and crotoxin, toxins predominantly in Crotalus durissus venom, exploring their recognition capacity, specificity, and cross-reactivity to snake venoms and its toxins. Initially, IgG purification employed affinity chromatography via protein A and G columns to segregate conventional antibodies (IgG1) from heavy chain antibodies (IgG2 and IgG3) of camelid isotypes sourced from Lama glama serum. Subsequent electrophoretic analysis (SDS-PAGE) revealed distinct bands corresponding to molecular weight profiles of IgG's fractions representing isotypes in Lama glama serum. ELISA cross-reactivity assays demonstrated all three IgG isotypes' ability to recognize the tested venoms. Notably, IgG1 exhibited the lowest interactivity in analyses involving bothropic and crotalic venoms. However, IgG2 and IgG3 displayed notable cross-reactivity, particularly with crotalic venoms and toxins, albeit with exceptions such as PLA2-CB, showing reduced reactivity, and C. atrox, where IgGs exhibited insignificant reactivity. In Western blot assays, IgG2 and IgG3 exhibited recognition of proteins within molecular weight (≈15 kDa) of C. d. collilineatus to C. d. terrificus, with some interaction observed even with bothropic proteins despite lower reactivity. These findings underscore the potential of camelid heavy-chain antibodies, suggesting Lama glama IgGs as prospective candidates for a novel class of serum therapies. However, further investigations are imperative to ascertain their suitability for serum therapy applications.

Study on the microscopic characteristics and hydration mechanism of thermo-alkali activated electrolytic manganese residue geopolymers

As a form of solid waste, electrolytic manganese residue (EMR) exhibits low reactivity, high sulfate content, and exceeds the standards for heavy metals. To address these drawbacks, a high-temperature thermal activation method was employed to enhance its reactivity and remove pollutants. The study investigated the physicochemical properties and leaching toxicity of EMR under different thermal activation conditions. Additionally, the thermally activated EMR was utilized in the preparation of geopolymer material, and the influence of EMR activation temperature, EMR content, sodium silicate content, and molar ratio on the mechanical properties, hydration mechanism, microstructure, and leaching toxicity of the EMR geopolymers was analyzed. The results indicated that after activation in the temperature range of 0–1200°C, the active content of silica-alumina in EMR increased, sulfate decomposition occurred, and the leaching of Mn2+ and NH4+-N decreased to 21.24 and 0.576 mg/L, respectively. When the activation temperature reached 1200°C, the compressive strength of the geopolymer, prepared with 50 % EMR, 50 % granulated blast furnace slag (GBFS), 30 % sodium silicate, and a molar ratio of 1.2, could reach 53.2 MPa at 28-day. Under activation in the range of 0–800°C, ettringite was abundant in the geopolymers, providing strength support. With activation in the range of 800–1200°C, the geopolymers became denser, exhibiting flaky and agglomerate gels. A diffraction peak appeared at 20°-40°(2θ) corresponding to C-(A)-S-H and N-S-A-H gels. Due to the slow depolymerization-polymerization kinetics of the EMR geopolymer and high sulfate content, the heat release rate and cumulative heat were significantly lower than ordinary portland cement (OPC). In the structure of EMR geopolymer, Mn2+ replaced Na+ and Ca2+ in the silicoaluminate structure or chemically bonded with anionic groups to the geopolymer. Simultaneously, Mn2+ participated in the formation of the EMR geopolymer gel, encapsulating within the gel. Therefore, the leaching of pollutants from EMR geopolymers met the standards of GB8978–1996.

Boosting peroxodisulfate activation by MIL-68(Fe) derived magnetic Fe3S4 nanosheets: Key role of sulfur vacancy

The peroxodisulfate (PDS) activation promoted by iron-based catalysts has captured ever-increasing attention in degrading organic contaminants. However, the difficulty in converting Fe(Ⅲ) to Fe(Ⅱ) greatly limits the generation of Fe(Ⅱ) and greatly inhabits the practical use of iron-based catalysts for PDS activation owing to the low reactivity between Fe(Ⅲ) and PDS. In this contribution, the magnetic Fe3S4 nanosheets with sulfur vacancy (SV) were synthesized by sulfuring MIL-68(Fe) with thioacetamide (TAA). Various characterizations, such as SEM, XRD, and XPS were employed to confirm the Fe3S4 catalyst, which was subsequently applied to activate PDS to degrade Rhodamine B (RhB). Fe3S4/PDS system exhibited superhigh RhB degradation performance without extra energy involvement, resulting in complete degradation in 5 min with 0.15 g/L Fe3S4 and 0.4 mM PDS. The enhanced RhB degradation performance could be attributed that the S-vacancy significantly promoted Fe(Ⅲ)/Fe(Ⅱ) cycle and nanosheet structure enabled well-exposure of active catalytic sites. EPR tests and quenching experiments proved that the Fe3S4 promoted the PDS activation in generating SO4•−, •OH, Fe(Ⅳ), and 1O2 to degrade RhB. We proposed possible RhB degradation pathway according to DFT calculations and HR-MS. T.E.S.T. analysis showed that most intermediates were less toxic than RhB, demonstrating that Fe3S4/PDS system was beneficial for RhB degradation.

Characterization and properties of phenolic resin doped modified lignin

Phenolic resins occupy an important position in industrial applications, but phenol, one of the raw materials for synthesis, is a non-renewable resource. Lignin, as a natural polymer containing phenolic hydroxyl groups, alcohol hydroxyl groups and other reactive groups, can replace some of the phenol in the synthesis of phenolic resins, which can reduce the amount of phenol, thus reducing the cost of phenolic resins, while effectively promoting the high value-added use of renewable biomass resources. Due to its low reactivity, alkaline lignin is usually discharged as production waste, unaware that lignin macromolecules can be modified. In this paper, the phenolic monomers were obtained by acid-catalyzed depolymerization of DES (choline chloride/p-toluenesulfonic acid or choline chloride/lactic acid) from waste alkaline lignin, and the recovery rate of the DES solution during the catalytic treatment was more than 85 %, in which the main monomer was 2-methoxy-4-(1-propyl) phenol. The degradation of alkaline lignin is still favorable after five times of DES solvent recovery. The depolymerized lignin monomer replaced phenol by 50 wt% and then ternary co-polymerized with phenol and formaldehyde to form a biomass phenol-based phenolic resin, providing a green route for phenolic resin production. The cost of resin preparation was economically calculated, and it was found that the cost of resin after accumulating 4 cycles of DES treatment was only 51.1 % of that of pure phenolic resin. The density functional theory (DFT) was used to simulate the possible radical reactions in the intermediate process of phenolic resin reaction, to explore the microscopic mechanism and competition, to provide theoretical reference for further experimental realization of resin structure control and optimization, and to improve the theoretical system of resin synthesis.

Social participation is associated with a habituated blood pressure response to recurrent stress

Lower cardiovascular reactivity is a proposed marker of motivational dysregulation and is related to a range of adverse behavioural and health outcomes. Social participation is a form of motivated behaviour and represents the frequency in which an individual engages in social activities. Low social participation has recently been linked to lower cardiovascular responses to acute psychological stress. With recent work emphasizing the importance of assessing adaptation of the cardiovascular response to recurrent stress, the aim of the current study is to build on previous work by examining the relationship between social participation and cardiovascular stress response adaptation. This study utilised data from the Pittsburgh Cold Study 3 (PCS 3). Two hundred and thirteen participants (M = 30.13; SD = 10.85) completed a social participation measure and had their systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) monitored across two separate standardized stress testing sessions. The testing sessions consisted of a 20-minute baseline and a 15-minute stress task. Results indicated that higher levels of social participation were associated with greater blood pressure habituation to recurrent stress, extending previous work identifying that social participation was associated with higher cardiovascular responses to stress. The present study identifies that those reporting greater levels of social participation may show enhanced stress tolerance when exposed to recurrent stress.

Unveiling methane sensing mechanisms of graphene and its derivatives

Natural gas has become one primary energy source. However, using natural gas imposes enormous challenges since natural gas leaks may cause catastrophic damage to the environment and human life. As the main component of natural gas, methane (CH4) is a type of greenhouse gas that exacerbates global warming and has a risk of explosion in air. Developing CH4 sensing technology is crucial to detect natural gas leaks. Despite tremendous efforts in exploring gas sensing by graphene and its derivatives, the low reactivity limited the application of graphene-based materials in CH4 detection. Here, density functional theory (DFT) calculations were carried out to study graphene and its derivatives’ CH4 adsorption energy, sensitivity, and selectivity. Graphene derivatives with hydroxyl groups around surface vacancies were found to be superior in CH4 sensing over other graphene derivatives. Our findings offer new design guidelines for developing CH4 sensors.

Bioorthogonal Cycloadditions of C3-Trifluoromethylated 1,2,4-Triazines with trans-Cyclooctenes.

1,2,4-triazines are a valuable class of heterodienes that can be employed in inverse electron-demand Diels-Alder reactions. However, their broader application in bioorthogonal chemistry is limited due to their low reactivity. This article focuses on 3-(trifluoromethyl)-1,2,4-triazines, which can be efficiently prepared in a one-pot reaction from NH-1,2,3-triazoles. These triazines are highly reactive in reactions with strained cyclooctenes, giving second-order rate constants as high as 230 M-1 s-1. Despite their high reactivity, the compounds remain sufficiently stable under biologically relevant conditions. We show that some of the compounds are fluorogenic, a property of potential use in bioimaging. In addition, we demonstrate the successful application of the triazines in labeling model biomolecules. Our work shows that the reactivity of 1,2,4-triazines can be enhanced by the 3-CF3-substitution, which we consider an important step toward the wider use of this promising class of reagents.

Theoretical investigation of DMPA-containing carbazole-based hole-transport materials for perovskite solar cells

This study mainly focuses on DFT and TD-DFT modelling and extensive analysis of eight carbazole-based molecules (MM, MPM, MP2.5M, MP2.6M, MP3.5M, MPPM, MP2P2M, and MP3P3M) as Hole Transporting Materials in Perovskite Solar cells. These compounds have in common the arm N3,N3,N6,N6-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (M) characterized by its strong ability to carry holes, low cost, and good stability. The molecule MM presents two arms without acceptor core, while other compounds present two arms separated by different acceptor cores: phenyl, biphenyl, pyridine or bipyridine. All under-probe compounds were favored candidates for HTMs in perovskite solar cells due to their excellent HOMO delocalization, reduced hole reorganization energies, lower chemical reactivity, longer radiative lifetimes, and spontaneous solvation processes. Flatness proved beneficial when the core consisted of two cycles, particularly for MP2P2M. The results showed that the HOMO levels were primarily influenced by M fragments in most of the molecules, while the LUMO levels were distributed across both the carbazole units and the cores. All molecules exhibited a more stable LUMO compared to that of Spiro-OMETAD, with MP2P2M showing a notably stable level, resulting in a narrower gap. The study found that, except for MP2P2M, these materials did not interfere with the perovskite layer and effectively filled pores. The incorporation of acceptor core groups improved the conjugation backbone and electronic states, significantly enhancing charge transport properties, particularly in molecules with a double ring structure. Furthermore, adding a pyridine center greatly increased solubility, especially in MP3P3M, suggesting that acceptor core inclusion benefits the solubility of the investigated HTMs. The use of two rings core was shown to enhance light harvesting efficiency, boost photocurrent generation, and improve charge transfer performance, particularly in MP2P2M, which is distinguished by its superior flatness, solubility, and charge transfer properties.

Highly reactive carbonated recycled concrete fines prepared via mechanochemical carbonation: Influence on the early performance of cement composites

Carbonated recycled concrete fines (RCF) possess the potential to serve as supplementary cementitious materials (SCMs). However, calcium carbonate (Cc) formed during traditional carbonation methods generally shows low reactivity. Moreover, the remaining calcium silicate hydrate (C-S-H) with a low Ca/Si ratio exhibits enhanced resistance to decalcification, leading to the formation of lower content of silica gels. These factors limit the reactivity and utilization of carbonated RCF in cementitious systems. In the present work, mechanochemistry was introduced into the RCF carbonation process, a technique named mechanochemical carbonation (MC), to enhance the reactivity of carbonated RCF. This study delved into the influence of MC-treated RCF (MCR) on the early performance of cement composites. The findings reveal that MCR exerted a more pronounced promotional effect on cement hydration, as demonstrated by the earlier appearance of hydration peaks for silicates and aluminates, coupled with increased peak intensity. This then resulted in a notable enhancement in early compressive strength. Specifically, with 10 wt% MCR, the compressive strength increased by approximately 19.9 % and 24.7 % at 1 d and 3 d, respectively. In comparison, samples incorporating wet carbonated RCF (WCR) demonstrated lower enhancements, with increases of only 4.5 % and 12.0 % at 1 d and 3 d, respectively. The enhanced performance of MCR can be attributed to the increased formation of nano-sized amorphous silica gels and metastable Cc. These components exhibit elevated reactivity and contribute to seeding effects, thereby promoting the overall reactivity and strength development of the cementitious system. These findings underscore the promising application potential of MC in transforming RCF into highly reactive SCMs.

1,6-Nucleophilic Di- and Trifluoromethylation of para-Quinone Methides with Me3SiCF2H/Me3SiCF3 Facilitated by CsF/18-Crown-6.

The direct 1,6-nucleophilic difluoromethylation, trifluoromethylation, and difluoroalkylation of para-quinone methides (p-QMs) with Me3SiRf (Rf = CF2H, CF3, CF2CF3, CF2COOEt, and CF2SPh) under mild conditions are described. Although Me3SiCF2H shows lower reactivity than Me3SiCF3, it can react with p-QMs promoted by CsF/18-Crown-6 to give structurally diverse difluoromethyl products in good yields. The products can then be further converted into fluoroalkylated para-quinone methides and α-fluoroalkylated diarylmethanes.

Mechanically robust, waterproof, fast curing lignin-based waterborne polyurethane with hierarchical hydrogen bonding network

The high-value utilization of lignin for preparing high performance and multifunctional waterborne polyurethane (WPU) is a fascinating subject but still a challenge due to its low reactivity. Herein, highly reactive lignin with low molecular weight of 1398 Da and high hydroxyl groups of 12 mmol/g was employed as biopolyol to directly polymerize with isocyanate to prepare lignin-based WPU (LWPU). The integration of lignin to polymer backbone was conducive to the construction of strong H-bond interactions and more rigid hard-segment-rich domains, achieving uniform and stable LWPU emulsions. When the lignin substitution amount was 40 %, the mechanical strength, Young’s modulus and toughness of the formed LWPU-40 films were improved to 12.51 and 272.25 MPa, 28.54 KJ/m3, increased by 13, 84 and 17 times than those of WPU, respectively, meanwhile the elongation at break was 370.44 %. Moreover, LWPU as coatings possessed fast film-forming ability, high adhesion strength, waterproofness and UV protection. Compared with commercial WPU (C-WPU), the surface and through drying time of LWPU-40 coating were shortened by 2 and 1.6 times, respectively. Moreover, the adhesive strength of LWPU-40 increased to 44.79 MPa, and could maintain initial 87.3 % after 48 h of water immersion. Therefore, this work proposes a novel insight of high-value utilization of lignin, simultaneously presents a feasible approach to develop high performance and multifunctional WPU coatings.

PISOX Copolyesters-Bio- and CO2-Based Marine-Degradable High-Performance Polyesters.

Oxalate esters and isosorbide serve as intriguing polymer building blocks, as they can be sourced from renewable resources, such as CO2 and glucose, and the resulting polyesters offer outstanding material properties. However, the low reactivity of the secondary hydroxyl groups makes it difficult to generate high-molecular-weight polymers from isosorbide. Combining diaryl oxalates with isosorbide appears to be a promising approach to produce high-molecular-weight isosorbide-based polyoxalates (PISOX). This strategy seems to be scalable, has a short polymerization time (<5 h), and uniquely, there is no need for a catalyst. PISOX demonstrates outstanding thermal, mechanical, and barrier properties; its barrier to oxygen is 35 times better than PLA, it possesses mechanical properties comparable to high-performance thermoplastics, and the glass transition temperature of 167 °C can be modified by comonomer incorporation. What makes this high-performance material truly exceptional is that it decomposes into CO2 and biomass in just a few months in soil under home-composting conditions and it hydrolyzes without enzymes present in less than a year in 20 °C water. This unique combination of properties has the potential to be utilized in a range of applications, such as biomedical uses, water-resistant coatings, compostable plastic bags for gardening and agriculture, and packaging plastics with diminished environmental impact.