Electronic Structures of Anti-Ferromagnetic Tetraradicals: <i>Ab Initio</i> and Semi-Empirical Studies

The energy relationships and electronic structures of the lowest-lying spin states in several anti-ferromagnetic tetraradical model systems are studied with high-level <i>ab initio</i> and semi-empirical methods. The Full-CI method (FCI), the complete active space second-order perturbation theory (CASPT2), and the <i>n</i>-electron valence state perturbation theory (NEVPT2) are employed to obtain reference results. By comparing the energy relationships predicted from the Heisenberg and Hubbard models with <i>ab initio</i> benchmarks, the accuracy of the widely used Heisenberg model for anti-ferromagnetic spin-coupling in low-spin polyradicals is cautiously tested in this work. It is found that the strength of electron correlation (|<i>U</i>/<i>t</i>|) concerning anti-ferromagnetically coupled radical centers could range widely from strong to moderate correlation regimes and could become another degree of freedom besides the spin multiplicity. Accordingly, the Heisenberg-type model works well in the regime of strong correlation, which reproduces well the energy relationships along with the wave functions of all the spin states. In moderately spin-correlated tetraradicals, the results of the prototype Heisenberg model deviate severely from those of multi-reference electron correlation <i>ab initio</i> methods, while the extended Heisenberg model, containing four-body terms, can introduce reasonable corrections and maintains its accuracy in this condition. In the weak correlation regime, both the prototype Heisenberg model and its extended forms containing higher-order correction terms will encounter difficulties. Meanwhile, the Hubbard model shows balanced accuracy from strong to weak correlation cases and can reproduce qualitatively correct electronic structures, which makes it more suitable for the study of anti-ferromagnetic coupling in polyradical systems

Development of a Coke Oven Gas Assisted Coal to Ethylene Glycol Process for High Techno-Economic Performance and Low Emission

Developing a coal to ethylene glycol (CtEG) process is of great interest to many countries, especially China. However, because the hydrogen to carbon ratio of the coal-gasified gas is far less than the desired value, the CtEG process suffers from high CO₂ emission and wastes precious carbon resources. At the same, most coke oven gas (COG) is discharged directly or used as fuel, resulting in a waste of resources, serious environmental pollution, and economic loss. To develop efficient and clean utilization of coal and COG resources, we propose a novel coke oven gas assisted coal to ethylene glycol (CaCtEG) process. The proposed process introduces the hydrogen-rich COG to adjust the hydrogen to carbon ratio and reduce CO₂ emission by integrating a dry methane reforming unit. Key operational parameters are investigated and optimized based on the established mathematical model. The advantages of the process are studied by a detailed techno-economic analysis. Results show that, compared with the conventional CtEG process, the CaCtEG process is promising since it increases the carbon element and exergy efficiency by 18.35% and 10.59%. The CO₂ emission ratio of the proposed process is reduced from 2.58 t/t-EG to 0.44 t/t-EG. From an economic point of view, the CaCtEG process can save production costs by 5.11% and increase the internal rate of return by 3.41%. The capital investment, however, is slightly increased because of the two additional units

Laser-Induced Graphene Electrodes on Poly(ether–ether–ketone)/PDMS Composite Films for Flexible Strain and Humidity Sensors

Laser-induced graphene prepared on polymer substrates with a high modulus is a widely applied method to fabricate varied flexible electronics; however, the resulting relatively poor stretchability considerably limits its applicability. In this paper, an elastic composite consisting of poly(ether–ether–ketone) powder and poly(dimethylsiloxane) (PDMS) is reported to fabricate stretchable electrodes using direct laser-induced graphitization without transferring. The liquid composites before curing can be cast into various shapes for different applications. To balance the conductivity and stretchability of stretchable electrodes, we optimized the composite mass ratios and laser parameters and performed a series of morphological and performance characterizations on the composites; furthermore, we analyzed the elemental composition and functional groups of the laser-induced products. With the proper encapsulating method, strain sensors were prepared, exhibiting high sensitivity (a gauge factor of 78) and a stable resistance response over 50% operating range with the ability to monitor both fine pulse beats and larger strains such as human joint movement. Furthermore, a humidity sensor composited with laser-patterned interdigital electrode and graphene oxide on the elastic composite substrate had characteristics of high sensitivity (14.18 pF/%RH) and fast recovery time (9 s), which could be used for breathing monitoring and noncontact sensing. In conclusion, laser-induced graphene prepared in one step on a stretchable composite film of polymers with a high modulus and low modulus is a promising method to fabricate wearable electronics

Docking accuracy enhanced by QM-derived protein charges

<p>Effects of protein polari sation on docking accuracy were investigated using molecular docking programme AutoDock 4 in which topology-specific empirical Gasteiger charges were replaced with Polarised protein-specific charges (PPC) to represent quantum mechanics- polarised protein. Docking was successfully conducted for 50 diverse protein–ligand complexes. The docking with PPC charges shows a decrease in the root-mean-square deviation (RMSD) values of ligands compared to those from the docking with Gasteiger charges. Ligand binding orientations and their key interactions such as hydrogen bonding interactions in X-ray structures were substantially reproduced in complexes docked using PPC scheme with 98% of the RMSDs of the best docking poses less than 2 Å compared to 74% in the docking with Gasteiger charges. Considerable improvements in docking accuracy were observed by simply altering the atomic partial charges in the scoring function, which reflects the importance of protein polarisation in molecular docking. Further research can be carried out to (1) include polarisation of both ligands and proteins to account for polarisation effects within protein and between protein and ligand, and (2) develop a PPC-based scoring function to increase the docking accuracies for protein–ligand complexes from a larger variety of protein families.</p

Sulfoxidation inside a <i>C</i>₃‑Vanadium(V) Bowl-Shaped Catalyst

The confined enantiopure oxido-vanadium complex <i>SSS-RRR-</i><b>1</b> was synthesized and tested as a catalyst for the oxidation of sulfides into sulfoxides. This catalyst is very efficient with a reaction rate more than 300 times higher than that of the model compound <i>SSS-RRR-</i><b>3</b>, and a turnover number (TON) close to 10⁵ was reached in combination with a good selectivity (more than 90%) in the sulfoxide product. Moreover, enantiomerically enriched sulfoxide can be obtained, breaking through the major limitation of the previous chiral vanatrane catalysts that show no detectable enantiomeric excess (ee). Further investigations revealed that the complex <i>SSS-RRR-</i><b>1</b> adopts a bowl-shaped structure with an open hydrophobic pocket. The microenvironment of the chiral pocket above the metal center accounts for the strong improvement in catalytic activity and enantioselectivity

HAT1 negatively regulate drought stress responses in Arabidopsis thaliana.

<p>(A) The phenotypes of Col-0, HAT1OX lines, <i>hat</i> mutants (<i>hat1</i>, <i>hat1hat3</i>) in response to progressive drought stress. Different genotype plants were grown in soil with sufficient water for 3 weeks (Watered), and then water was withheld for 10 d (Progressive drought), and the photos were taken. (B) Water loss from detached leaves of different genotype plants. Leaves at similar developmental stages were excised and weighed at the indicated time after detachment. The proportion of fresh weight losses was calculated on the basis of the initial weight of the leaves. Data are shown as mean SD of three independent experiments. The significance of difference was analyzed by Student’s t test (**P < 0.01). (C-E) Growth of Col-0, <i>HAT1OX</i> lines, <i>hat1</i> mutants (<i>hat1</i>, <i>hat1hat3</i>) in response to mild drought stress. 3-week-old plants were subjected to mild drought treatment and the images of both drought-treated plants (right) and the well-watered plants (left) were taken (C). (D) Water loss from the peat pellets during the duration of the experiment. Control soil water content was maintained at a constant value of 2.2 g water g^-1 dry soil (solid line) during the entire experiment. For the mild drought condition, soil water content was maintained at 0.7g H₂O g^-1 dry soil. (E) The change in biomass under mild drought among different genotypes compared to Col-0. After mild drought treatment, all the replications of the drought-treated and the well-watered control were harvested and the dry weights (biomass) were measured. Then calculate the reduction in biomass. Bars indicate SD calculated from three independent experiments. The significance of difference was analyzed by Student’s t test and Asterisks indicate significant difference from the wild type (*P < 0.05, **P < 0.01).</p

Formulation of pH-Responsive Methacrylate-Based Polyelectrolyte-Stabilized Nanoparticles for Applications in Drug Delivery

pH-responsive polyelectrolytes, including methacrylate-based anionic copolymers (MACs), are widely used as enteric coatings and matrices in oral drug delivery. Despite their widespread use in these macroscopic applications, the molecular understanding of their use as stabilizers for nanoparticles (NPs) is lacking. Here, we investigate how MACs can be used to create NPs for therapeutic drug delivery and the role of MAC molecular properties on the assembly of NPs via flash nanoprecipitation. The NP size is tuned from 59 to 454 nm by changing the degree of neutralization, ionic strength, total mass concentration, and the core-to-MAC ratio. The NP size is determined by the volume of hydrophilic domains on the surface relative to the volume of hydrophobic domains in the core. We calculate the dimensions of the hydrophobic NP core relative to the thickness of the polyelectrolyte layer over a range of ionizations. Importantly, the results are shown to apply to both high-molecular-weight polymers as core materials and small-molecule drugs. The pH responsiveness of MAC-stabilized NPs is also demonstrated. Future development of polyelectrolyte copolymer-stabilized nanomedicines will benefit from the guiding principles established in this study

Additional file 1 of Metabolome and transcriptome analyses reveal changes of rapeseed in response to ABA signal during early seedling development

Supplementary Material

Supplementary document for Thermal tuning nanoprinting based on liquid crystal tunable dual-layered metasurfaces for optical information encryption - 6798346.pdf

Supporting informatio

Standardized Iterative Genome Editing Method for Escherichia coli Based on CRISPR-Cas9

The introduction of complex biosynthetic pathways into the hosts’ chromosomes is gaining attention with the development of synthetic biology. While CRISPR-Cas9 has been widely employed for gene knock-in, the process of multigene insertion remains cumbersome due to laborious and empirical gene cloning procedures. To address this, we devised a standardized iterative genome editing system for Escherichia coli, harnessing the power of CRISPR-Cas9 and MetClo assembly. This comprehensive toolkit comprises two fundamental elements based on the Golden Gate standard for modular assembly of sgRNA or CRISPR arrays and donor DNAs. We achieved a gene insertion efficiency of up to 100%, targeting a single locus. Expression of tracrRNA using a strong promoter enhances multiplex genomic insertion efficiency to 7.3%, compared with 0.76% when a native promoter is used. To demonstrate the robust capabilities of this genome editing toolbox, we successfully integrated 5–10 genes from the coenzyme B12 biosynthetic pathway ranging from 5.3 to 8 Kb in length into the chromosome of E. coli chassis cells, resulting in 14 antibiotic-free, plasmid-free producers. Following an extensive screening process involving genes from diverse sources, cistronic design modifications, and chromosome repositioning, we obtained a recombinant strain yielding 1.49 mg L–1 coenzyme B12, the highest known titer achieved by using E. coli as the producer. Illuminating its user-friendliness, this genome editing system is an exceedingly versatile tool for expediently integrating complex biosynthetic pathway genes into hosts’ genomes, thus facilitating pathway optimization for chemical production