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The creation of Cu0/Cu+interface over Cu-based catalysts is known to facilitate the production of multi-carbon (C2+) products during CO2reduction reaction (CO2RR). However, the Cu+moieties exhibit high susceptibility towards reduction into Cu0at a high current density. Thus, a comprehensive understanding and rational shaping strategy for the construction and stabilization of Cu0/Cu+interface in Cu-based catalysts is imperative. Herein, we proposed a controllable “nanoparticle assembly” strategy to obtain hollow spherical assemblies (HSA) composed of numerous Cu2O nanoparticles (HSA-Cu2O). The HSA-Cu2O catalysts significantly enhance the selectivity of C2+products, resulting in an impressive overall Faraday efficiency (FE) of 79.2% ± 0.7% at a partial current density of 317.1 mA cm−2. The HSA-Cu2O catalysts undergo in-situelectrochemically reconstruction during CO2RR, achieving Cu0/Cu+interfacial sites with a high density. The Auger electron spectra, in-situRaman, and morphological evolution studies have confirmed that the combination of the Cu0/Cu+interface and hollow sphere architecture facilitated the concentration of *CO intermediates, thereby promoting C–C dimerization to boost C2+selectivity in CO2RR.

The oxygen evolution reaction (OER) performance of ruthenium-based oxides strongly correlates with the electronic structures of Ru. However, the widely adopted monometal doping method unidirectionally regulates only the electronic structures, often failing to balance the activity and stability. Here, we propose an “elastic electron transfer” strategy to achieve bidirectional optimization of the electronic structures of Sr, Cr codoped RuO2catalysts for acidic OER. The introduction of electron-withdrawing Sr intrinsically activates the Ru sites by increasing the oxidation state of Ru. Simultaneously, Cr acts as an electron buffer, donating electrons to Ru in the presence of Sr in the as-prepared catalysts and absorbing excess electrons from Sr leaching during the OER. Such a bidirectional regulation feature of Cr prevents overoxidation of Ru and maintains its high oxidation state during the OER. The optimal Ru3Cr1Sr0.175catalyst exhibits a low overpotential (214 mV @ 10 mA cm–2) and excellent stability (over 300 h).

Miniaturized spin-exchange relaxation-free (SERF) magnetometers are recognized for their exceptional sensitivity and ability to function without the need for cryogenic cooling. These devices are particularly valuable for detecting ultra-weak magnetic fields, such as those generated by the human brain. However, the use of miniaturized SERF magnetometers has been limited due to their narrow bandwidth. In this study, we developed a compact triaxial SERF magnetometer that incorporates closed-loop feedback, significantly broadening its bandwidth to 1.1 kHz. This magnetometer achieves high sensitivity, approximately 35 fT/(Hz)1/2 across each axis and remains compact, with dimensions of $13.8\times 21.0\times 44.0$ mm. It accurately measured the time course of pulsed sinusoidal magnetic fields, with each pulse containing a single cycle of a 1030 Hz sinusoidal signal at a 1 pT amplitude. Our magnetometer also successfully detected various magnetic fields generated by the human brain, including alpha rhythms, auditory evoked fields (AEFs), and steady-state visual evoked fields. Looking forward, this high-bandwidth, high-sensitivity, and compact triaxial SERF magnetometer showcases its great potential for advancing magnetoencephalography (MEG) and opening new research avenues in neuroscience and clinical research.

Mogrosides are natural compounds highly valued in the food sector for their exceptional sweetness. Here, we report a novel O-glycosyltransferase (UGT74DD1) from Siraitia grosvenoriithat catalyzes the conversion of mogrol to mogroside IIE. Site-directed mutagenesis yielded the UGT74DD1-W351A mutant, which exhibited the new capability to transform mogroside IIE into the valuable sweetener mogroside III, but with low catalytic activity. Subsequently, using structure-guided directed evolution with combinatorial active-site saturation testing, the superior mutant M6 (W351A/Q373 K/E49H/Q335W/S278C/D17F) were obtained, which showed a 46.1-fold increase in catalytic activity compared to UGT74DD1-W351A. Molecular dynamics simulations suggested that the enhanced activity and extended substrate profiles of M6 are due to its enlarged substrate-binding pocket and strengthened enzyme–substrate hydrogen bonding interactions. Overall, we redesigned UGT74DD1, yielding mutants that catalyze the conversion of mogrol into mogroside III. This study thus broadens the toolbox of UGTs capable of catalyzing the formation of valuable polyglycoside compounds.

Cigarette draw resistance and filter pressure drop are both critical physical indicators for the tobacco industry, which use testing equipment to measure the two parameters. Pressure drop standards are used as transfer standards to ensure the accuracy and reliability of the testing equipment. Pressure drop standards are generally cylindrical rods having a certain number of parallel capillaries. To address the issue of how to design and fabricate pressure drop standards quickly and conveniently, this paper proposes a design method for pressure drop standards based on structural parameters. The method uses a mathematical model of the internal airflow of the standard including the entrance effect into a circular capillary and uses an iterative calculation algorithm accordingly. By iterative calculation, the structural parameters of the pressure drop standard, namely, diameter and length of the capillaries, were obtained, along with the relationship between the draw resistance of the standard and the flow rate in each capillary. The accuracy of the mathematical model was validated by comparing and analyzing the experimental and theoretical draw resistance of standards with different structural parameters. The experimental results showed that the relative error between the measured draw resistance and the calculated draw resistance was below 8%, which proves the reliability and validity of the mathematical model, and provides theoretical support for the design and fabrication of pressure drop standards.

The construction and modification of novel energetic frameworks to achieve an ideal balance between high energy density and good stability are a continuous pursuit for researchers. In this work, a fused [5,6,5]-tricyclic framework was utilized as the energetic host to encapsulate the oxidant molecules for the first time. A series of new pyridazine-based [5,6] and [5,6,5] fused polycyclic nitrogen-rich skeletons and their derivatives were designed and synthesized. Two strategies, amino oxidation and host–guest inclusion, were used to modify the skeleton in only one step. All compounds exhibit good comprehensive properties (Td (onset)> 200 °C, ρ > 1.85 g cm–3, Dv> 8400 m s–1, IS > 20 J, FS > 360 N). Benefiting from the pyridazine-based fused tricyclic structure with more hydrogen bonding units and larger conjugated systems, the first example of [5,6,5]-tricyclic host–guest energetic material triamino-9H-pyrazolo[3,4-d][1,2,4]triazolo[4,3-b]pyridazine-diperchloric acid (10), shows high decomposition temperature (Td (onset)= 336 °C), high density and heats of formation (ρ = 1.94 g cm–3, ΔHf= 733.4 kJ mol–1), high detonation performance (Dv= 8820 m s–1, P= 36.2 GPa), high specific impulse (Isp= 269 s), and low sensitivity (IS = 30 J, FS > 360 N). The comprehensive performance of 10is superior to that of high-energy explosive RDX and heat-resistant explosives such as HNS and LLM-105. 10has the potential to become a comprehensive advanced energetic material that simultaneously satisfies the requirements of high-energy and low-sensitivity explosives, heat-resistant explosives, and solid propellants. This work may give new insights into the construction and modification of a nitrogen-rich polycyclic framework and broaden the applications of fused polycyclic framework for the development of host–guest energetic materials.

Detection of intracellular miRNAs, especially sensitive imaging of in vivo miRNAs, is vital to the precise prediction and timely prevention of tumorgenesis but remains a technical challenge in terms of nuclease resistance and signal amplification. Here, we demonstrate a gold nanoparticle-based spherical nucleic acid-mediated spatial matching-guided nonenzymatic DNA circuit (SSDC) for efficient screening of intracellular miRNAs and, in turn, finding cancerous tissues in living organisms before the appearance of clinical symptoms. Due to the substantially enhanced nuclease resistance, the false positive signal is avoided even in a complex biological medium. Target miRNA can straighten out the hairpin DNA probe to be linear, allowing the probe to penetrate into the internal region of a core/shell DNA-functionalized signal nanoampfilier and initiate a strand displacement reaction, generating an amplified fluorescence signal. The detection limit is as low as 17 pM, and miRNA imaging is in good accordance with the gold standard polymerase chain reaction method. The ability to image intracellular miRNAs is substantially superior to that of conventional fluorescence in situ hybridization techniques, making in vivo SSDC-based imaging competent for the precise prediction of tumorigenesis. By intratumoral chemotherapy guided by SSDC-based imaging, tumorigenesis and progression are efficiently controlled before the onset of clinical symptoms.

Background: Polymyxin B is considered a last-line therapeutic option against multidrug-resistant gram-negative bacteria, especially in COVID-19 coinfections or other serious infections. However, the risk of antimicrobial resistance and its spread to the environment should be brought to the forefront. Methods: Pandoraea pnomenusaM202 was isolated under selection with 8 mg/L polymyxin B from hospital sewage and then was sequenced by the PacBio RS II and Illumina HiSeq 4000 platforms. Mating experiments were performed to evaluate the transfer of the major facilitator superfamily (MFS) transporter in genomic islands (GIs) to Escherichia coli25DN. The recombinant E. colistrain Mrc-3 harboring MFS transporter encoding gene FKQ53_RS21695 was also constructed. The influence of efflux pump inhibitors (EPIs) on MICs was determined. The mechanism of polymyxin B excretion mediated by FKQ53_RS21695 was investigated by Discovery Studio 2.0 based on homology modeling. Results: The MIC of polymyxin B for the multidrug-resistant bacterial strain P. pnomenusaM202, isolated from hospital sewage, was 96 mg/L. GI-M202a, harboring an MFS transporter-encoding gene and conjugative transfer protein-encoding genes of the type IV secretion system, was identified in P. pnomenusaM202. The mating experiment between M202 and E. coli25DN reflected the transferability of polymyxin B resistance via GI-M202a. EPI and heterogeneous expression assays also suggested that the MFS transporter gene FKQ53_RS21695 in GI-M202a was responsible for polymyxin B resistance. Molecular docking revealed that the polymyxin B fatty acyl group inserts into the hydrophobic region of the transmembrane core with Pi-alkyl and unfavorable bump interactions, and then polymyxin B rotates around Tyr43 to externally display the peptide group during the efflux process, accompanied by an inward-to-outward conformational change in the MFS transporter. Additionally, verapamil and CCCP exhibited significant inhibition via competition for binding sites. Conclusions: These findings demonstrated that GI-M202a along with the MFS transporter FKQ53_RS21695 in P. pnomenusaM202 could mediate the transmission of polymyxin B resistance.

Stimulus-responsive polymers have found widespread use in biomedicine due to their ability to alter their own structure in response to various stimuli, including internal factors such as pH, reactive oxygen species (ROS), and enzymes, as well as external factors like light. In the context of atherosclerotic cardiovascular diseases (CVDs), stimulus-response polymers have been extensively employed for the preparation of smart nanocarriers that can deliver therapeutic and diagnostic drugs specifically to inflammatory lesions. Compared with traditional drug delivery systems, stimulus-responsive nanosystems offer higher sensitivity, greater versatility, wider applicability, and enhanced biosafety. Recent research has made significant contributions towards designing stimulus-responsive polymer nanosystems for CVDs diagnosis and treatment. This review summarizes recent advances in this field by classifying stimulus-responsive polymer nanocarriers according to different responsiveness types and describing numerous stimuli relevant to these materials. Additionally, we discuss various applications of stimulus-responsive polymer nanomaterials in CVDs theranostics. We hope that this review will provide valuable insights into optimizing the design of stimulus-response polymers for accelerating their clinical application in diagnosing and treating CVDs.

The extensive application of nonlinear components and power electronic devices in power systems has led to increasingly deteriorating harmonic pollution. The rapid and high-precision harmonic detection and analysis technology will set the prerequisite for mitigating the harmonic crisis. This article presents a robust, stable, and real-time approach based on broad learning system (BLS) for detecting and analyzing the amplitudes of fundamental and harmonic components, which only requires half or even quarter cycle input. Additionally, a fast-converging adaptive parameter learning strategy using rectified adaptive moment estimation (RAdam) for BLS is proposed. To obtain the actual distorted signals, the signal acquisition system is built on the basis of the designed multi-pulse rectifier power supply (6/18 pulse). With the fundamental frequency deviation, interharmonics and noise, etc., the simulated signals synthesized by MATLAB tool and the actual signals acquired from the built system are attained to verify the performance of methods. The proposed approach differentiates from other existing methods not only due to its superior precision and robustness in the presence of multitudinous interference factors but also its real-time performance because of low average computing time.

A series of manganese-based oxide catalysts were synthesized by the hydrothermal method. By adjusting the doping amounts of W and Cu in the system to study the catalytic performance of transition metal-doped manganese oxides on soot combustion. They were deeply studied through various characterizations and theoretical calculations. The results show that W and Cu doping modifications can significantly improve the activity of manganese-based oxides in soot oxidation. W-Cu 0.1 /MnO x prepared by co-modification of W and Cu at 395 °C can convert 90% of soot into CO 2. The multiple characterization results show that by adjusting the doping amount of copper and tungsten, the nano-flower-like morphology can be obtained and the crystal plane can be reconstructed, which is helpful to increase the specific surface area, Mn3+ content, and oxygen vacancy content. The theoretical calculation results show that the oxygen vacancy on the surface of the catalyst shows the ability to activate O 2 and H 2 O, and they show non-competitive adsorption. In addition, W-Cu 0.1 /MnO x has a good application prospect in the catalytic oxidation of soot because of its excellent catalytic stability. This work provides a reference for the design and preparation of non-noble metal-based catalysts for the elimination of soot particles from diesel engine exhaust. [ABSTRACT FROM AUTHOR]

[Display omitted] Catalytic oxidation for soot emissions from diesel engines is a major post-processing technology, but limited by the lack of efficient catalysts. Herein, a series of MnCeO x catalysts with different Mn/Ce molar ratios were prepared by the traditional hydrothermal (tr-MnCeO x) and MOFs derivatization method (M-MnCeO x), and mechanism behind for soot combustion were investigated by several techniques and density functional theory (DFT) calculations. Encouragingly, N 2 adsorption–desorption result demonstrates M-MnCeO x has a larger specific surface area, thus increasing the number of active sites and contact efficiency between soot and catalysts. Further, XPS, H 2 -TPR observations manifest the appropriate Ce doping would promote the generation of oxygen vacancy through the redox cycle of Ce4+ + Mn3+ ↔ Mn4+ + Ce3+, thereby improving the catalytic performance for soot combustion. More importantly, the DFT calculations indicate that MOFs-derived 2Mn1Ce-200 possesses the lowest oxygen vacancy formation energy and stronger affinity for both O 2 and H 2 O, which is favorable for the generation of active oxygen species. Among all catalysts, the 2Mn1Ce (Mn/Ce molar ratio of 2:1) exhibited the highest catalytic activity under tight contact with T 90 value of 360 °C, and maintained good stability. Our work provides guidance for developing catalysts with tunable physicochemical properties. [ABSTRACT FROM AUTHOR]

The problem of load nonlinearity is exposed as more and more load types are introduced into the radar power system. The nonlinear load is easy to produce large harmonic current, but at the same time it seriously threatens the normal and safe operation of other system equipment. How to design shunt active power filter (APF) to eliminate the harmonic effect of load and achieve stability as well reliability is a difficult problem for radar power system working at 115 V 400 Hz. This paper designs a hybrid optimization shunt active power filter, which can quickly detect and compensate harmonics, mainly includes fast harmonic detection module, space vector modulation module, composite control module and inverter module. Furthermore, the modeling and simulation of the hybrid optimization shunt APF are completed in MATLAB/Simulink software, and the parameters of radar power system are also redesigned. The simulation results suggest that, under heavy load conditions, the total harmonic distortion (THD) of the radar power side current is below 4.96%, and the short-period meaning filter only needs 0.0035 s to enter a new steady state in the face of load mutation. The APF designed in this paper can effectively suppress the harmonics in the radar power system, and greatly improve the dynamic performance while ensuring the steady-state performance of the system.

ABSTRACTForest covers about one-third of the land area of the conterminous United States (CONUS) and plays an important role in offsetting carbon emissions and supporting local economies. Growing interest in forests as relatively cost-effective nature-based climate solutions, particularly restoration and reforestation activities has increased the demand for information on forest regrowth and recovery following natural and anthropogenic disturbances (e.g. fire, harvest, or thinning). However, a wall-to-wall mapping of the CONUS tree regrowth duration at an annual time interval and 30-m resolution is still challenging. In this study, we utilized the annual land cover products to develop a dataset to quantify forest regrowth duration for CONUS over 1985–2017. The land cover data used to derive the tree regrowth duration map is from the primary land cover product in the U.S. Geological Survey’s Land Change Monitoring, Assessment, and Projection (LCMAP) collection. The LCMAP product used all available Landsat images to detect disturbances over forest and classify Grass/Shrub to Tree Cover transitions on an annual basis. The average regrowth duration was then calculated for each pixel. The regrowth duration map was validated using human-interpreted annual reference data that were collected independently. The validation results show 1 year of underestimation and 6-year standard deviation of error between the reference data and the regrowth duration map. In southeastern CONUS, where major tree regrowth activities have been observed, our map showed higher accuracy with less than one-year bias and 3.6 years standard deviation of error. Forest in the southeast took around 5 years to recover, which was faster than other regions of CONUS. Many pixels had multiple disturbances during the 33-year study period in the region. The spatial pattern of the tree regrowth indicated intense harvesting activities in this region. The Pacific Northwest coast region was the second main area of tree regrowth, but this region often took multiple decades to recover. Given the increasing interest in forests as nature-based climate solutions, the tree regrowth duration map can be used to assess reforestation activities as well as forest recovery following natural disturbance and harvesting.

AbstractChinese hazelnut was chosen to become a probable precursor of biological active peptides via computer simulations in this article. There were a large number of bioactive peptides in Chinese hazelnut sequences according to analytical results from the BIOPEP database. The most prominent of these was the inhibitory peptide for dipeptidyl peptidase-IV (DPP-IV; EC 3.4.14.5), which can be used to treat type 2 diabetes, so the theoretical method to obtain DPP-IV inhibitory peptides by hydrolysis with a single or combination of enzymes was studied. Cytotoxicity analysis performed by ToxinPred showed that all of the DPP-IV inhibitory peptides generated from protein hydrolysis were not cytotoxic. Structural interaction fingerprint analysis revealed that Asp663 and Phe357 may be important residues for ligand binding. In order to further understand the inhibitory mechanism of peptide, VR with lowest half maximum inhibitory concentration (IC50) and IPI (inhibitors have been reported) were selected as ligand of DPP-IV to perform steered molecular dynamics simulations and PMF calculations. The results showed that P1 is the preferred (un)binding tunnel for the inhibitors obtained. Our findings help in the development of new DPP-IV inhibitors which were derived from common food.Communicated by Ramaswamy H. Sarma

The hydrological process in the dry–warm valley of the mountainous area of southwest China has unique characteristics and has attracted scientific attention worldwide. Given that this is an area with fragile ecosystems and intensive water resource conflicts in the upper reaches of the Yangtze River, a systematic identification of its hydrological responses to climate and land use variations needs to be performed. In this study, MIKE SHE was employed and calibrated for the Anning River Basin in the dry–warm valley. Subsequently, a deep learning neural network model of the long short-term memory (LSTM) and a traditional multi-model ensemble mean (MMEM) method were used for an ensemble of 31 global climate models (GCMs) for climate projection. The cellular automata–Markov model was implemented to project the spatial pattern of land use considering climatic, social, and economic conditions. Four sets of climate projections and three sets of land use projections were generated and fed into the MIKE SHE to project hydrologic responses from 2021 to 2050. For the calibration and first validation periods of the daily simulation, the coefficients of determination (R) were 0.85 and 0.87 and the Nash–Sutcliffe efficiency values were 0.72 and 0.73, respectively. The advanced LSTM performed better than the traditional MMEM method for daily temperature and monthly precipitation. The average monthly temperature projection under representative concentration pathway 8.5 (RCP8.5) was expected to be slightly higher than that under RCP4.5; this is contrary to the average monthly precipitation from June to October. The variations in streamflow and actual evapotranspiration (ET) were both more sensitive to climate change than to land use change. There was no significant relationship between the variations in streamflow and the ET in the study area. This work could provide general variation conditions and a range of hydrologic responses to complex and changing environments, thereby assisting with stochastic uncertainty and optimizing water resource management in critical regions.

•A clear nonlinear relationship between public transportation accessibility and land price.•Introducing the adjusted Gaussian two-step floating catchment area method into this relationship.•In-depth analysis of the impact of accessibility on land price is carried out using the SHAP.

Oil/water separation has become a global challenge as more and more oily wastewater is generated from oil spills and industrial wastewater. Super-wetting fuctional materials in oil-water separation has obvious advantages such as high efficiency, simple craft and potential to intelligentialize. But traditional superhydrophobic/superlipophilic oil-water separation material is easily blocked and damaged by oil. Here, a temperature-sensitive superhydrophilic/underwater superoleophobic switch device (TS-PNIPAM-Ni) was prepared using a poly-N-isopropylacrylamide (PNIPAM) hydrogel and magnetic hydrophobic foamed nickel through a one-step solution dipping method. The separation efficiency of TS-PNIPAM-Ni to dichloroethane-water can reach up to 100% and maintain a separation efficiency of more than 99.9% after the completion of 10 separation cycles, and the oil-water separation stops above 34 °C and captures water droplets intelligently. The micro-morphology, micro-structure and components of TS-PNIPAM-Ni and PNIPAM were analyzed with FTIR, SEM and EDS. The TS-PNIPAM-Ni shows excellent superhydrophilic/underwater superoleophobicity, good temperature sensitivity and magnetic navigation function.The temperature-sensitive superhydrophilic/underwater superoleophobic switch device (TS-PNIPAM-Ni) was prepared using the poly-N-isopropylacrylamide (PNIPAM) hydrogel and the magnetic hydrophobic foamed nickel through the one-step solution dipping method.The device has ultra-high oil-water separation efficiency, magnetic responsiveness, can absorb water directionally and has temperature responsiveness, futhermore, it can intelligently control the progress of oil-water separation.

Skin wounds are usually accompanied by bacterial infections and inflammations, leading to delayed wound healing, which remain a great challenge in clinical treatment. Therefore, it is of great significance to develop wound dressings that inhibit bacterial infections to accelerate wound healing. Herein, we reported the fabrication of inclusion complex (a β-cyclodextrin covalent organic framework loaded with enrofloxacin and flunixin meglumine)-incorporated electrospun thermoplastic polyurethane fibers (named ENR-FM-COF-TPU) via electrospinning. The obtained ENR-FM-COF-TPU fibrous membrane exhibited excellent physicochemical and biological properties such as uniform and stable morphology, proper hydrophobicity, good water uptake capacity, and admirable biocompatibility, which showed perfect behavior as a wound dressing. In addition, the ENR-FM-COF-TPU membrane achieved a sustained drug release of enrofloxacin and flunixin meglumine and displayed powerful antibacterial activity against Staphylococcus aureusand Escherichia coliwith 99% inhibitory efficiency for 50 h. More importantly, the wound healing therapy effect was investigated using a full-thickness skin defect model of mice. It suggested that the ENR-FM-COF-TPU membrane could significantly accelerate and enhance wound healing through downregulating inflammatory cytokines (IL-1β and TNF-α) and increasing the expression of growth factors (VEGF and EGF). Due to its excellent properties, the ENR-FM-COF-TPU membrane may have promising potential in wound healing applications.

MON 87419 was one of the new transgenic corn events developed in US with the trait of herbicide resistance to both dicambaand glyphosate. To monitor unintended release of genetically modified organism in the future, as well as to meet GM-labeling requirements, it is requisite to develop a reliable method for the detection and quantification of MON 87419, an event-specific primer pair was designed to amplify the 3′-junction site between the endogenous genome sequence and the transferred DNA of GM event MON 87419, amplicons of desired size were produced by qualitative polymerase chain reaction (PCR) assay. For the validation of this quantitative method, the mixed samples containing 10%, 1%, and 0.1% MON 87419 ingredient were quantified. The precisions were expressed as relative standard deviations, deviated by 7.87%, 12.94%, and 19.98%, respectively. These results clearly demonstrate that the PCR methods we developed herein can be used for event-specific quantitative testing of the double-herbicide-resistant corn MON 87419.Graphical AbstractStandard curves of the real-time PCR method of genetically modified corn MON 87419.

Experimental determination of equilibrium solubility of 1-(2-bromophenyl)-pyrrole-2,5-dione in binary aqueous solutions containing a co-solvent of isopropanol, ethanol, N-methyl-2-pyrrolidinone (NMP) or methanol over temperatures from 278.15 to 323.15 K was made by the shake-flask technique under local pressure of 101.2 kPa. At the identical experimental conditions (temperature and mass fraction compositions of co-solvents), the maximum equilibrium solubility magnitude in a mole fraction of 1-(2-bromophenyl)-pyrrole-2,5-dione was recorded in the NMP (1) + water (2) system; and the minimum one, in the isopropanol (1) + water (2) system. The solvent effect was quantitatively analyzed by employing the KAT-LSER model, representing the solubility parameter and dipolarity–polarizability had main contributions to the solubility variation at 298.15 K. Four relationships, such as the Jouyban–Acree model, modified Wilson model, Jouyban–Acree–van’t Hoff model, and mixture response surface (MRS) model, were employed to correlate the determined solubility magnitudes, attaining the root-mean-square deviations of no higher than 493.0 × 10–5and relative average deviations of no higher than 5.59%. The molecule interactions of solute–solvent and solvent–solvent were investigated through the extended Hildebrand solubility approach. In water-rich composition regions, there was some association between 1-(2-bromophenyl)-pyrrole-2,5-dione and solution. Furthermore, the local mole fractions of isopropanol (ethanol, NMP, or methanol) and water nearby 1-(2-bromophenyl)-pyrrole-2,5-dione were quantitatively evaluated by the inverse Kirkwood–Buff integrals. 1-(2-Bromophenyl)-pyrrole-2,5-dione was preferentially solvated by water in water-rich proportions; while in co-solvent-rich proportions for the solutions studied, it was preferentially solvated by isopropanol (ethanol, NMP, or methanol). In water-rich ranges, 1-(2-bromophenyl)-pyrrole-2,5-dione could be predominantly serving as a Lewis base in front of water molecules.

Communicated by Ramaswamy H. Sarma

Topological asymmetry is an important factor to change the phase diagram of AB-type block copolymer with respect to the volume fraction of A-blocks from symmetric to asymmetric. However, many topology-asymmetric AB-type block copolymers can only produce limited effects on the asymmetry of phase diagrams, such as (AB)nstar and ABnmiktoarm star copolymers. In this work, we investigate the self-assembly behavior of an A1(A2B)nmiktoarm star copolymer composed of one A1-arm and nA2B-arms using self-consistent field theory, aiming to demonstrate that the asymmetry of the phase diagram can be largely tuned by controlling nand the ratio of the volume fraction fA1of A1-block to the total volume fraction fof A-blocks, τ = fA1/f. Note that this copolymer with τ = 0 is reduced to (AB)nstar copolymer while it is reduced to ABnmiktoarm star copolymer with τ = 1. For n≥ 2, the asymmetry of the phase diagram changes nonmonotonically and exhibits a maximum as τ increases from 0 to 1, and the maximal degree of asymmetry increases with increasing n. In the phase diagram of maximal asymmetry with n= 5, the phase boundaries of A-sphere/A-cylinder and A-gyroid/lamella are deflected to f≈ 0.56 and f≈ 0.76 at a moderate segregation strength, respectively. As a result, the regions of both Frank–Kasper σ and A15 phases are dramatically expanded in such a highly asymmetric phase diagram. Moreover, the gyroid region exhibits a very complex changing trend with increasing τ, even vanishing in a certain range of τ for n≥ 3. Surprisingly, the A1(A2B)3copolymer with an optimized τ ≈ 0.6 exhibits the largest gyroid region with a width of about ΔfG≈ 0.187 at χN= 60, which is about 4 times that at τ = 0 and 13 times that at τ = 1. The gyroid morphology with the volume fraction of channels ranging from f≈ 0.54 to f≈ 0.73 is promising in applications.