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To effectively alleviate the ever-increasing energy crisis and environmental issues, clean and sustainable energy-related materials as well as the corresponding storage/conversion devices are in urgent demand. Silicon (Si) with the second most elemental abundance on the crust in the form of silicate or silica (SiO2) minerals, is an advanced emerging material showing high performance in energy-related fields (e.g. batteries, photocatalytic hydrogen evolution). For the improved performance in industry-scale applications, Si materials with delicate nanostructures and ideal compositions in a massive production are highly cherished. On account of the reserve, low cost and diverse micro-nanostructures, silicate minerals are proposed as promising raw materials. In the article, crystal structures and the reduction approaches for silicate minerals, as well as recent progress on the as-reduced Si products for clean energy storage/conversion, are presented systematically. Moreover, some cutting-edge fields involving Si materials are discussed, which may offer deep insights into the rational design of advanced Si nanostructures for extended energy-related fields.

Facile fabrication of the ultra-high-performance adsorbent can effectively ameliorate the Cr(VI)-pollution elimination in sewage control. Herein, a simple synthesis strategy is proposed to tap a versatile chelating resin poly(pyrogallol-tetraethylene pentamine) (PPTA) with respect to Cr(VI) removal from solution. Multiple changing factors which affect the adsorption behavior of PPTA are explored sequentially, such as initial pH, adsorbate concentration, adsorbent dosage, temperature, foreign ions etc. The microstructure and functional mechanism of synthetic adsorbent are investigated systematically by means of various characterizations including TEM, EDS, FT-IR, XPS, etc. Consequently, as-prepared PPTA-3 microsphere by the reactant ratio of 1: 1 represents a brilliant synergistic adsorption and reduction result for Cr(VI) by the drastic electrostatic interaction of -NH3+ and -OH2+ groups, including satisfactory removal efficiency which closes to 100 % in low concentration, favorable specificity for the influence from coexistent ions (Mo(VI), Mn(VII), Cl-, Cr(III), etc), and passable recyclability. Following the surpassingly fitting with Langmuir isotherm model, its maximum capacity reaches 714.29 mg g-1 at 30 °C. The removal performance is essentially in agreement with the pseudo-second-order kinetics, simultaneously, suffers the rate-limiting impact depending on intra-particle diffusion process. In brief, this newly developed chelating resin presents an effective means with regard to the Cr(VI)-wastewater treatment or other uses in the future.

The oxygen evolution process is a crucial part determining the total reaction kinetics of electrocatalytic overall water splitting for clean hydrogen production. However, for some semiconductor materials, e.g. tin dioxide (SnO2) and tungsten oxide (WO3), the water oxidation process generally proceeds following the two-electron pathway with rather high driving potential for the generation of hydrogen peroxide (H2O2 or HO2−). In this work, efficient electronic configuration modulation of SnO2 nanoparticles was realized by non-metallic phosphorus (P) doping, giving rise to the considerable transformation into a four-electron transfer-governed water oxidation reaction with the electrocatalytic activity even comparable to the benchmark RuO2 nanoparticles. These results validate the great potential in remarkably tuning the electrocatalytic performance of transition metal compound electrocatalysts with non-metallic element dopants.

Chiral amine-squaramide is a kind of effective hydrogen bond donor bifunctional catalyst to promote many asymmetric transformations. In this paper, novel chiral tertiary amine-squaramide derived from the natural product of the stevioside was developed and applied into the asymmetric Michael addition of acetylacetone to nitroolefins. This asymmetric reaction performed well, and a series of enantiomerically enriched compounds were obtained in high yields (up to 96%) with excellent enantioselectivities (up to 99% ee).

In this study, porous calcium silicate (CS) ceramics with oriented arrangement of lamellar macropore structure were prepared by directional freeze casting method. The lamellar macropores were connected by the micropores on the pore wall, which had good pore interconnectivity. The effects of solid loading of the slurry, freezing temperature, sintering additive content, and sintering temperature on the microstructures and compressive strength of the synthesized porous materials were investigated systematically. The results showed that with the increase of solid loading (≤20 vol%) and sintering additive content, the sizes of lamellar pores and pore walls increased gradually, the open porosity decreased and the compressive strength increased. The sintering temperature had little effect on the pore size of the ceramics, but increasing the sintering temperature (≤1050 °C) promoted the densification of the pore wall, reduced the porosity, and improved the strength. The decrease of freezing temperature had little effect on porosity, but it reduced the size of lamellar pore and pore wall, so as to improve the strength. Finally, porous CS ceramics with lamellar macropores of about 300–600 μm and 2–10 μm micropores on the pore wall were obtained. The porous CS ceramics had high pore interconnectivity, an open porosity of 66.25% and a compressive strength of 5.47 MPa, which was expected to be used in bone tissue engineering.

In this study, the novel tin-based catalysts (Sn(II)/PN@AC) were prepared using the phosphorus and nitrogen dual-modified activated carbon as support and SnCl2 as active compounds, as well as then evaluated in acetylene hydrochlorination. Under the reaction temperature of 180 °C and an acetylene gas hourly space velocity (GHSV-C2H2) of 30 h–1, the 15%Sn(II)/PN@AC-550 showed the initial acetylene conversion of 100% and vinyl chloride selectivity over 98.5%. Additionally, the deactivation rate of 15%Sn(II)/PN@AC-550 reached 0.47% h–1, which was lower than that of 15%Sn(II)/AC-550 (1.02% h–1), suggesting that PN@AC-550 as novel support can retarded the deactivation of Sn(II)/AC-550 catalysts during acetylene hydrochlorination. Based on the catalytic tests and characterization results (XRD, Raman, BET surface area, TEM, C2H2-TPD, H2-TPR, XPS, FT-IR, TGA, and ICP), it demonstrated that PN@AC-550 as support could effectively improve the dispersion of tin species, retard the formation of coke deposition, lessen the oxidation of SnCl2 during the preparation process, as well as relatively inhibit the leach of tin species during the reaction. By combing the FTIR results and Rideal–Eley mechanism, we proposed that that HSnCl3 was transition state of SnCl2 in catalysis acetylene hydrochlorination and then adsorbed the acetylene to produce the vinyl chloride.

At present, screen printing is the most widely used technique in the printed electronics industry and the printed pattern can satisfy certain electronic application requirements. Ink development is the most important part of the printing process. In this paper, a new particle-free MOD ink (MOD = metal–organic-decomposition) was synthesized from silver malonate, diethanolamine (DEA) and ethylene glycol (EG). Silver malonate was the precursor of silver. DEA was the complexing agent that maked silver malonate soluble. EG acted not only as a solvent to regulate the rheological properties of the ink, but also as a reducing agent to reduce silver ions. The decomposition temperature was reduced from 210 °C to about 100 °C by the formation of silver-amine complex, thus the selection range of substrate could be broadened. The ink was spread on the polyimide (PI) substrate by screen printing. The silver film was formed after heat treatment at 150 °C for 1 h and its electrical conductivity can reach 1.0 × 104 S cm−1, which corresponded to one sixty-third of the theoretical conductivity of the bulk silver (6.3 × 105 S cm−1).

Four polyaniline-tea saponin (PTS) nanocomposites were prepared by an in-situ polymerization with tea saponin (TS) as a biosurfactant, and they were used to remove organic dyes from aqueous solution. The PTS nanocomposites were characterized by using field emission scanning electron microscopy, the Fourier transform infrared spectroscopy, the Ultraviolet-visible spectroscopy, and the thermogravimetric analysis. The adsorption performances of the PTS nanocomposites for organic dyes were studied by a static adsorption method. The experimental results reveal that adsorption capacities of the PTS nanocomposites are higher than that of pure polyaniline. Especially, the PTS nanocomposites exhibit excellent adsorption performances for anionic dyes because of the electrostatic interaction between the positively charged nitrogen atoms on the PTS chains and the negatively charged sulfonate ions in the anionic dyes. According to the adsorption kinetics and thermodynamics results, the adsorption processes of PTS20 for CR and AB74 follow well with the pseudo second-order and Langmuir isotherm models. It is indicated that TS should be very useful in the preparation of PTS nanocomposite and in removal of toxic dyes from waste water.

Probing the dynamic evolution of active species under different sensing conditions is achieved to the rational design of sensing materials for outstanding sensing performance. In this study, a palladium (Pd)-loaded ZnO sensing material was approached via the impregnation method. The Pd-loaded ZnO₁₀₀ gas sensor has a better H₂ sensing performance than a pure ZnO gas sensor at an operating temperature of 190 to 360 °C. The in situ Raman and H₂ temperature-programmed surface reaction characterization technologies confirmed that the synergistic effect of metal Pd (Pd⁰) and Pd oxide (PdOₓ) played a decisive role in improving the sensing capability for H₂ in low concentrations (less than 100 ppm). The proportion of Pd⁰ in the Pd/PdOₓ dynamically increased with the elevation of operating temperature. The small size Pd/PdOₓ dispersed on the ZnO surface enhanced the dissociation of H₂ by Pd⁰ and the charge transfer between PdOₓ and ZnO, boosting the sensing performance of the gas sensor to H₂. With the increase of the operating temperature to more than 360 °C, H₂ was directly oxidized to gaseous H₂O on the Pd/PdOₓ active sites, resulting in a relatively low H₂ sensing capacity. In addition, the change of the appropriate Pd/PdOₓ ratio could effectively improve the H₂ sensing performance of the gas sensor.

In this paper, TiO2 decorated reduced graphene oxide nanocomposite (TiO2@RGO), synthesized with the help of 3-Triethoxysilylpropylamine (APTES), was utilized to reinforce polyimide (PI), and the me...

In the Loess Plateau in Northern China, repeated freeze-thaw (FT) cycles deteriorate the strength and structure of loess as a foundation soil, resulting in the instability or failure of supporting structure. Lignosulfonate is an eco-material, utilized as an effective and nontraditional stabilizer to improve the engineering properties of metastable soils. A series of laboratory tests, including unconfined compression tests, cyclic loading-unloading tests and scanning electron microscopy, on calcium lignosulfonate (CL)- and sodium lignosulfonate (SL)-stabilized loess were performed to investigate the stabilization effect, deterioration mechanisms of the FT cycles, and the resistance to FT cycles. Two traditional stabilizers, quicklime (QL) and sodium silicate (SS), were selected, and the engineering properties of QL- and SS-stabilized loess were compared with those of CL- and SL-stabilized loess. The results showed that the strength values of CL- and SL-stabilized loess specimens decreased by 34.2% and 50% respectively, after 20 FT cycles, whereas those of the traditionally SS- and QL- stabilized specimens decreased by 85.3% and 82.87%, respectively. The elastic moduli of SL- and QL-stabilized loess specimens decreased by 22.1% and 92.0%, respectively. The mean energy dissipations of nontraditionally treated specimens also decreased significantly less than those of traditionally treated specimens. Overall, the results showed CL and SL had better stabilization effects on engineering properties of loess than QL and SS, and their stabilized loess specimens exhibited stronger resistance to FT cycles. The study findings demonstrated the significant potential of lignosulfonate for extensive application in cold loess areas.

The reduction of nitrogen-containing heterocyclic compounds in aqueous medium under mild condition is quite challenging. In view of metal–organic frameworks (MOFs) possess adjustable pore size and modifiable organic linkers, MOFs could be used in heterogeneous catalysis. Herein, Three Nano-Ni-MOFs, MOF-74-Ni, MOF-69-Ni, and Ni–NH2 (constructed from similar ligands and Ni2+ ions) are introduced for hydrogenating of azacyclo-compounds. As expected, Ni–NH2 shows outstanding activity of hydrogenation of quinoline under mild conditions, due to the moderate pore size and the modified –NH2 function group, which makes the substrate anchored on the surface of the framework facilitate the following catalysis process. Theoretical calculations identified that the –NH2 group at the catalyst facilitates the H2 heterolytic dissociation for the hydrogenation reactions. Compared to MOF-74-Ni and MOF-69-Ni, the catalyst of Ni–NH2 shows outstanding activity of hydrogenation of quinoline, due to the modified –NH2 function group which makes the substrate anchored on the surface of the framework facilitate the following catalysis process

To develop a new class of neutral fluorescent dyes with mitochondrial staining capacity, a series of functional dyes were obtained from Nile Red (2a–e) and coumarin (3a–e) with different amide compounds via Suzuki coupling reactions. The Nile Red derivatives (2a–e) emitted red fluorescence (590–660 nm) and coumarin derivatives (3a–e) showed blue emission (455–490 nm) in organic solvents. In addition, they exhibited high fluorescence quantum yields (0.27–0.98) in organic solvents and excellent photostability (>92%). Moreover, all of them possessed low cytotoxicity. More importantly, Nile Red borate (2) and coumarin borate (3) only accumulated in lipid droplets, while after being modified by different amide compounds, dyes 2a–e and 3a–e could successfully target mitochondria in HeLa cancer cells via confocal fluorescence experiments. This work provides a new strategy for the design of neutral cellular probes for mitochondrial staining.

Background To analyze mechanisms of action of glucocorticoid treatment for endoplasmic reticulum stress (ERS) in sensorineural hearing loss (SNHL), we aimed to evaluate the expression and activation status of the protein kinase RNA-like ER kinase (PERK)–C/EBP homologous protein (CHOP) pathway, which is the major pathway in the ERS. Methods In the present study, we established an in vitro ERS model using tunicamycin-treated hair-cell-like HEI-OC1 cells. The effect of dexamethasone on proliferation inhibition, apoptosis, and ATF4–CHOP pathway in HEI-OC1 cells was examined by CCK-8 assay, flow cytometry, western blotting, and reverse transcription PCR, respectively. Results In HEI-OC1 cells, dexamethasone was shown to significantly reduce the tunicamycin-induced expression of ATF4 and CHOP in the context of sustained viability and proliferation, a therapeutic effect that was reversible by co-treatment with a glucocorticoid antagonist. Conclusion Dexamethasone can protect hair-cell-like HEI-OC1 cells from ERS damage, which may be one of the mechanisms of action for GCs in SNHL treatment.

Diketopyrrolopyrroles (DPP) have been recognized as a promising acceptor unit for construction of semiconducting donor-acceptor (D-A) polymers, which are typically flanked by spacers such as thiophene rings via a carbon-carbon single bond formation. It may suffer from a decrease in the coplanarity of the molecules especially when bulky side chains are installed. In this work, the two N atoms in the DPP unit are further fused with C-3 of the two flanking thiophene rings, yielding a p-expanded, very planar fused-ring building block (DPPFu). A novel DPPFu-based D-A copolymer (PBDTT-DPPFu) was successfully synthesized, consisting of a benzo[1,2-b:4,5-b]dithiophene (BDTT) unit as a donor and a DPPFu unit as an acceptor. For comparison, the unfused DPP-based counterpart PBDTT-DPP was also synthesized. Two dodecyl alkyl chains were attached to thiophene rings of DPP moieties to ensure good solubility of the DPPFu-based polymer. The influence of the ring-fusion effect on their structure, photophysical properties, electronic properties, molecular packing, and charge transport properties is investigated. Ring-fusion enhances the intermolecular interactions of PBDTT-DPPFu polymer chains as indicated by density functional theory calculation and analysis of electrostatic potential and van der Waals potential and results in significantly improved molecular packing for both the in-plane and out-of-plane directions as suggested by X-ray measurements. Finally, we correlate the molecular packing to the device performance by fabricating field-effect transistors based on these two polymers. The charge carrier mobility of the ring-fused polymer PBDTT-DPPFu is significantly higher as compared to the PBDTT-DPP polymer without ring-fusion, although PBDTT-DPPFu exhibited a much lower number-average molecular weight of 17 kDa as compared to PBDTT-DPP with a molecular weight of 108 kDa. The results from our comparative study provide a robust way to increase the interchain interaction by ring-fusion-promoted coplanarity. Funding Agencies|Swedish Research CouncilSwedish Research CouncilEuropean Commission [2015-04853, 2016-06146, 2019-04683]; Swedish Research Council FormasSwedish Research CouncilSwedish Research Council Formas; NSFCNational Natural Science Foundation of China (NSFC) [21504006, 21534003, 11272093]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [2017.0186, 2016.0059]; Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research; China Scholarship CouncilChina Scholarship Council [201908440047]; Guangzhou Municipal Science and Technology Bureau [201804010501, 201904010381, 202002030362]; Department of Education of Guangdong ProvinceNational Natural Science Foundation of Guangdong Province [2018GKTSCX041, 2017GKQNCX005]; Department of Science and Technology of Guangdong Province [2016A010103046]; Open Fund of the State Key Laboratory of Luminescent Materials and Devices (South China University of Technology) [2020-skllmd-07]; Natural Science Foundation of Hunan ProvinceNatural Science Foundation of Hunan Province [2018JJ3098]; Office of Science, Office of Basic Energy Sciences, of the U.S. Department of EnergyUnited States Department of Energy (DOE) [DE-AC02-05CH11231]

In this work, we attempt to figure out alkoxy-substitution effects on two kinds of well-known non-fullerene acceptors (NFAs), IDT-series and Y-series acceptors, by placing alkoxy side chains on the β-positions of the outer thiophene units. The resulting molecules, named IDTN-O and Y6-O, exhibit different properties compared to the original acceptors named IDTN and Y6. The HOMO and LUMO levels of IDTN-O are slightly upshifted at the same time, which causes a slightly higher open-circuit voltage (Voc) without sacrificing the short-circuit current density (Jsc) of the devices. J71:IDTN-O blend films can also achieve a better blend morphology due to the conformational locking effect and higher dipole moment induced by the alkoxy groups, which helps achieve a higher fill factor (FF). In addition, Y6-O exhibits significantly upshifted LUMO levels compared to Y6, leading to a high Voc of 0.95 V. PM6:Y6-O blend films can also maintain an optimal blend morphology through side-chain engineering, which leads to an excellent FF of 78.0%. As a result of alkoxy substitution, both IDTN-O and Y6-O-based devices can achieve better performances of 12.1% and 16.6% than IDTN and Y6-based devices (10.9% and 15.7%), which indicates that this is an effective method to optimize these two types of NFAs.

Brassica napus is an important oilseed crop in the world and the mechanism of seed oil biosynthesis in B. napus remains unclear. In order to study the mechanism of oil biosynthesis and generate germplasms for breeding, an EMS mutant population with ~100,000 M2 lines was generated using Zhongshuang 11 as the parent line. The EMS-induced genome-wide mutations in M2-M4 plants were assessed. The average number of mutations including single nucleotide polymorphisms and insertion/deletion in M2-M4 was 21,177, 28,675 and 17,915, respectively. The effects of the mutations on gene function were predicted in M2-M4 mutants, respectively. We screened the seeds from 98,113 M2 lines and 9,415 seed oil content and fatty acid mutants were identified. We further confirmed 686 mutants with altered seed oil content and fatty acid in advanced generation (M4 seeds). Five representative M4 mutants with increased oleic acid were re-sequenced and the potential causal variations in FAD2 and ROD1 genes were identified. This study generated and screened a large scale of B. napus EMS mutant population and the identified mutants could provide useful genetic resources for the study of oil biosynthesis and genetic improvement of seed oil content and fatty acid composition of B. napus in the future. Accepted version This research was supported by The National Key Research and Development Program of China (2016YFD0101000) and the National Natural Science Foundation of China (31871658).

CYP1A1 was induced in lung of mice by LPS treatment with an aryl hydrocarbon receptor‐independent manner, while Toll‐like receptor 4 knockout abolished CYP1A1 overexpression. CYP1A1 deficiency elevated pro‐inflammatory cytokines in lung tissues of septic mice by targeting NF‐κB (p65) and increased lung injury in response to LPS or E. coli challenge., Acute lung injury (ALI) is accompanied by overactivation of multiple pro‐inflammatory factors. Cytochrome P450 1A1 (CYP1A1) has been shown to aggravate lung injury in response to hyperoxia. However, the relationship between CYP1A1 and lipopolysaccharide (LPS)‐induced ALI is unknown. In this study, CYP1A1 was shown to be upregulated in mouse lung in response to LPS. Using CYP1A1‐deficient (CYP1A1−/−) mice, we found that CYP1A1 knockout enhanced LPS‐induced ALI, as evidenced by increased TNF‐α, IL‐1β, IL‐6, and nitric oxide in lung; these effects were mediated by overactivation of NF‐κB and iNOS. Furthermore, we found that aspartate aminotransferase, lactate dehydrogenase, creatine kinase, and creatinine levels were elevated in serum of LPS‐induced CYP1A1−/− mice. Altogether, these data provide novel insights into the involvement of CYP1A1 in LPS‐induced lung injury.

N-halamine-containing mesoporous silica was prepared by treating the silica with (3-(trimethoxysilyl) propyl methacrylate), followed by grafting reaction of an N-halamine precursor, 3-(3′-hydroxypropyl)-5,5-dimethylhydantoin (APDMH). The resulting N-halamine mesoporous silica was applied to the surface of cotton by a coating process. The coated cotton showed good static and dynamic hydrophobic properties (static contact angle, 138.91°). After soaking in household bleach, N-halamines were formed on the coated fabric, which provided good antimicrobial properties against Gram-positive bacteria, Gram-negative bacteria, and fungi. The chlorinated sample inactivated 98.93% of Staphylococcus epidermidis, 97.83% of Escherichia coli O157:H7 and 82.24% of Candida albicans within 60 min, respectively. The coated and chlorinated samples showed high hydrophobicity toward other water-based liquids such as coffee, cola, green tea and milk. Further, the chlorinated fabric samples degraded ammonia in aqueous solutions. These attractive functions make the new N-halamine mesoporous silica coated cotton fabrics as an excellent candidate of multipurpose functional fibrous materials.

Regulating the states of hydrogen bonds in ionic liquids (ILs) is an effective way to improve their catalytic performance. In this paper, disulfonic-functionalized acidic ionic liquids (DSFAILs) were synthesized successfully, including novel SO3H-functionalized binuclear IL (bis[3-(CH2)3SO3H-1-(CH2)2-Im][HSO4]2). For the biodiesel synthesis, compared with the traditional ILs catalysts, DSFAILs bis[(3-(CH2)3SO3H-1-(CH2)2-Im][HSO4]2, [Im(N (CH2)3SO3H)2][HSO4]) had higher catalytic activity even under mild reaction conditions. Using the density functional theory (DFT) method, the role of hydrogen bonds in different SO3H-functionalized acidic ionic liquids (SFAILs) was explored. The forms of hydrogen bonds existing in different ILs directly determine their acidity. It suggested that the forming status of the active sites (hydrogen bonds) were diverse in different SFAILs. Also, deep ionization of the hydrogen atoms from the cation-anion strong interaction could increase the acidity and catalytic performance of SFAILs. From this, the structure-activity relationship between the SFAILs structures and the catalytic activity of methyl oleate synthesis was proposed. Besides, the experimental results also showed that bis[3-(CH2)3SO3H-1-(CH2)2-Im][HSO4]2 catalyst had a high catalytic activity to obtain methyl oleate and the catalyst could be separated easily owing to its larger molecular weight. However, [Im(N(CH2)3SO3H)2][HSO4] had a stronger acidity and a lower steric hindrance and thus a higher catalytic activity and was the optimal catalyst for the methyl oleate synthesis. In the presence of a small amount of catalyst (6 wt %) and at low reaction temperature (353 K), the methyl oleate yield could reach up to 93%. After six recycles of the catalyst, the methyl oleate yield remained at 90%.

In this study, we synthesized a new organic-inorganic hybrid material based on N-halamine and TiO2 using miniemulsion polymerization. N-halamine as a broad-spectrum antimicrobial agent has a more p...

In recent years, with the emergence of various kinds of drug-resistant bacteria, existing antibiotics have become inefficient in killing these bacteria, and the formation of biofilms has further weakened the therapeutic effect. More problematically, the massive use and abuse of antibiotics have caused severe side effects. Thus, the development of ultra-efficient and safe antibacterial systems is urgently needed. Herein, a photodynamic therapy (PDT)-driven CO-controlled delivery system (Ce6&CO@FADP) is developed for synergistic antibacterial and ablation biofilms. Ce6&CO@FADP is constructed using a fluorinated amphiphilic dendritic peptide (FADP) and physically loaded with Ce6 and CORM-401. After efficiently entering the bacteria, Ce6&CO@FADP can rapidly release CO intracellularly by the massive consumption of the H2O2 generated during the PDT process, without affecting the generation of singlet oxygen (1O2). As such, the combination of CO and 1O2 exerts notable synergistic antibacterial and biofilm ablation effects both in vitro and in vivo (including subcutaneous bacterial infection and biofilm catheter models) experiments. More importantly, all biosafety assessments suggest the good biocompatibility of Ce6&CO@FADP. Together, these results reveal that Ce6&CO@FADP is an efficient and safe antibacterial system, which has essential application prospects for the treatment of bacterial infections and ablation of biofilms in vivo.

Facile preparation of hyperbranched polymers (HPs) has been advanced tremendously by the use of either various multifunctional agent-mediated controlled living radical polymerizations or a highly reactive ABx unit-modulated self-stepwise polymerizations. However, it remains, to our knowledge, a significant challenge to prepare HPs with simultaneously precisely controlled degree of branching (DB) and biorelevant signal-triggered degradation property for controlled release applications due to the respective limitations of the aforementioned two strategies. For this purpose, a triple functional AB2 unit, A-SS-B2 chain transfer agent (AB2 CTA), that integrates the merits of both multifunctional agents and highly reactive ABx units was designed and synthesized successfully to include a disulfide bond for reduction-triggered polymer degradation toward promoted intracellular release of encapsulated cargoes, a trithiocarbonate group for a universal reversible addition-fragmentation chain transfer (RAFT) polymerization of any vinyl-based monomer, and three terminal groups consisting of one azide and two alkyne functions for the generation of hyperbranched topology via a self-click coupling-based polymerization. A subsequent self-click polymerization of the resulting AB2 CTA by click coupling in the presence of CuSO4·5H2O and sodium ascorbate (NaVc) generated a hyperbranched polymer template (HPT) with precisely modulated DB and a plurality of CTA units for a universal reversible addition-fragmentation chain transfer (RAFT) polymerization of any vinyl-containing monomer. The HPT was next used as a multimacro-CTA for RAFT polymerization of a typical hydrophilic monomer, oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA), to demonstrate the potential of this HPT for a robust and facile production of bioreducible hyperbranched polymers for controlled release applications. The synthesized HPT-4-POEGMA can form unimolecular micelles with enhanced stability due to the hyperbranched structure, and the size of micelles varied in the range from 82.4 to 140.3 nm by a modulation of the molar feed ratio of monomer to HPT and polymerization time. More importantly, HPT-POEGMA micelles incubated with 10 mM glutathione (GSH) showed reduction-triggered cleavage of the disulfide links and polymer degradation for promoted intracellular doxorubicin (DOX) release and enhanced therapeutic efficiency. Taken together, this triple functional AB2 CTA provided a powerful means for the facile preparation of bioreducible hyperbranched polymers with precisely controlled DB for controlled release applications.

Surface functionalization tailors the interfacial properties without impacts on the mechanical strength, which is beneficial for industry and daily applications of various metallic materials. Herein, a two-step surface functionalization strategy, (1) catechol-mediated immobilization of clickable agent and (2) postfunctionalization based on thiol–ene click reaction, is achieved using a copolymer, namely poly[2-(methacryloyloxy)ethylundec-10-enoate]-co-(N-(3,4-dihydroxyphenethyl) methacrylamide) [P(MEUE-co-DPMAm)]. To reduce the potential side reactions of allylic double bonds in allyl methacrylate during the polymerization, the MEUE are designed and synthesized with better control over the polymer chain growth. The surface functionalization via the two-step method is demonstrated using various thiols, e.g., hydrophobic, hydrophilic, and polymeric thiols under room conditions. Additionally, the hydrophobic-thiol-functionalized anodic aluminum oxide is found to be a candidate for the oil/water separation with a separation efficiency of ∼99.2%. This surface modifier provides practical insights into the further design of functional materials.

Reinforcement of the interfacial interaction between epoxy adhesives and metallic materials was achieved by using poly(glycidyl methacrylate) (PGMA) with N-(3,4-dihydroxyphenethyl)methacrylamide (D...

In this study, silane-modified polypyrrole (PPy) was coated onto cotton fabrics through a conventional “in situ polymerization” method. And by chlorination with NaClO solution, we obtained antimicrobial conductive PPy/Si–Cl–cotton fabrics. The PPy/Si–Cl–cotton fabrics were characterized by scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared and thermogravimetric analysis. Also, the electrical conductivity property, antibacterial property, and ultraviolet light stability of the coated fabrics were tested. The PPy/Si–Cl–cotton fabrics showed antimicrobial and electrical conductivity properties when the chlorination time was up to 30 s. The chlorine content was 0.30 wt% and the resistance was 26.79 kΩ/cm. The PPy/Si–Cl–cotton fabrics (Cl+% 0.30) showed excellent antibacterial properties against 100% Staphylococcus aureus and 100% Escherichia coli O157:H7 were inactivated within 1 min of contact. Due to the proportional relationship of the electrical conductivity and chlorine content of the PPy/Si–Cl–cotton fabrics, the electrical conductivity of the PPy/Si–Cl–cotton fabrics can be used for monitoring the antimicrobial activity.

In recent years, rock pyrolysis parameters combined with a mass balance method have been used to calculate the hydrocarbon expulsion efficiency. However, due to the experimental procedure of rock pyrolysis, the residual hydrocarbon amount (S1) is underestimated, and the hydrocarbon-generation potential of kerogen (S2) is overestimated, so that the hydrocarbon expulsion efficiency calculated from the pyrolysis parameters before correction is higher than the actual value. In this paper, the pyrolysis parameters were corrected by performing pyrolysis before and after the extraction of source rocks, and the hydrocarbon expulsion efficiency of the mudstone of the Qing 1 member of the Ha14 well in Songliao basin was calculated using the chemical kinetics method. The hydrocarbon expulsion efficiencies before and after the correction were considerably different, the hydrocarbon expulsion efficiency of the Ha14 well after correction was 17.5% lower than that before correction. The study show that the higher the abundance and maturity of source rock are, the higher the hydrocarbon expulsion efficiency is; the oil-type organic matter has a higher hydrocarbon-expulsion efficiency than the gas-type organic matter; the interbedded sand and mud type source-reservoir configuration relationship is beneficial to hydrocarbon expulsion; the underwater diversion channel phase has the highest hydrocarbon expulsion efficiency.

The formation of ground-level ozone (O3) is dependent on both atmospheric chemical processes and meteorological factors. Traditional models have difficulty assessing O3 formation sensitivity in a timely manner due to the limitations of flexibility and computational efficiency. In this study, a random forest (RF) model coupled with the reactivity of volatile organic compound (VOC) species was used to investigate the O3 formation sensitivity in Beijing from 2014 to 2016, and evaluate the relative importance (RI) of chemical and meteorological factors to O3 formation. The results showed that the O3 prediction performance using initial concentrations of VOC species (R2 = 0.87) was better than that using total VOCs (TVOCs) concentrations (R2 = 0.77). Meanwhile, the RIs of VOC species correlated well with their O3 formation potentials (OFPs). O3 formation presented a negative response to NOx, PM2.5 and relative humidity, and a positive response to temperature, solar radiation and VOCs. The O3 isopleth curves calculated by the RF model were generally comparable with those calculated by the box model. O3 formation shifted from a VOC-limited regime to a transition regime from 2014 to 2016. This study demonstrates that the RF model coupled with the initial concentrations of VOC species could provide an accurate, flexible, and computationally efficient approach for O3 sensitivity analysis.

Volatile organic compounds (VOCs) tend to be consumed by atmospheric oxidants, resulting in substantial photochemical loss during transport. An observation-based model is used to evaluate the influence of photochemical loss of VOCs on the sensitivity regime and mechanisms of ozone formation. Our results showed that a VOC-limited regime based on the observed VOC concentrations shifted to a transition regime with the photochemical initial concentration of VOCs (PIC-VOCs) in the morning. The net ozone formation rate was underestimated by 3 ppb h−1 (36 ppb day−1) based on the PIC-VOCs. The relative contribution of the RO2 path to ozone production based on the PIC-VOCs accordingly increased by 13.4 %, particularly, the contribution of alkenes derived RO2 increased around 10.2 %. The contribution of local photochemistry might be underestimated to both local and regional ozone pollution if the consumed VOCs was not accounted for, and policy-making on ozone pollution prevention should focus on high-reactivity VOCs.

BACKGROUND: The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is an important mediator of neuroinflammatory responses that regulates inflammatory injury following cerebral ischemia and may be a potential target. Salidroside (Sal) has good anti-inflammatory effects; however, it remains unclear whether Sal can regulate NLRP3 inflammasome activation through the Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway after cerebral ischemia to alleviate inflammatory injury. METHODS: We established an oxygen-glucose deprivation and reoxygenation (OGD/R) model of BV2 cells and a middle cerebral artery occlusion/reperfusion (MCAO/R) rat model. Cell Counting Kit-8 (CCK-8), flow cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay were used to detect the viability and apoptosis of BV2 cells. Enzyme-linked immunosorbent assay (ELISA) was used to detect the level of inflammatory factors. 2,3,5-triphenyltetrazolium chloride (TTC) staining and modified Neurological Severity Score (mNSS) were used to detect cerebral infarction volume and neurological deficit in rats. Western blot, immunohistochemistry and immunofluorescence staining were used to detect the protein expression levels. RESULTS: Our results showed that Sal increased viability, inhibited lactate dehydrogenase (LDH) release, and reduced apoptosis in OGD/R-induced BV2 cells. Sal reduced the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-8. Following induction by OGD/R, BV2 cells exhibited NLRP3 inflammasome activation and increased protein levels of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, IL-1β, and IL-18. Protein levels of key TLR4 signaling pathway elements, such as TLR4, myeloid differentiation primary response 88 (MyD88), and phosphorylated nuclear factor kappa B p65 (p-NF-κB p65)/NF-κB p65 were upregulated. Interestingly, it was revealed that Sal could reverse these changes. In addition, TAK242, a specific inhibitor of TLR4, had the same effect as Sal treatment on BV2 cells following induction by OGD/R. In the MCAO/R rat model, Sal was also observed to inhibit NLRP3 inflammasome activation in microglia, reduce cerebral infarction volume, and inhibit apoptosis. CONCLUSIONS: In summary, we found that Sal inhibited NLRP3 inflammasome activation and apoptosis in microglia induced by cerebral ischemia/reperfusion injury by inhibiting the TLR4/NF-κB signaling pathway, thus playing a protective role. Therefore, Sal may be a promising drug for the clinical treatment of ischemic stroke.

The pathophysiology of septic acute kidney injury (AKI) is very complex and the fatality is high. Nrf2 is crucial for septic AKI, and dihydromyricetin (DMY) has a protective effect on LPS-induced AKI. We aimed to explore whether DMY could affect Nrf2 pathway by regulating miR-199b-3p and played a protective role in septic AKI. The mouse model was induced by cecal ligation and puncture (CLP) and the cell model was stimulated by LPS. Enzyme-linked immunosorbent assay was conducted to examine MDA, SOD, LDH, GSH, TNF-α, kidney injury molecule 1 (KIM-1), and IL-6 levels. The pathological changes were observed by hematoxylin–eosin staining. The targeted relationship between miR-199b-3p and Nrf2 was verified by a dual-luciferase reporter assay. Levels of SOD, GSH, NQO-1, Nrf2, and HO-1 were decreased, MDA, LDH, TNF-α, IL-6, and KIM-1, and miR-199b-3p were increased in the CLP group and LPS-induced HK-2 cells, while the effect was reversed after DMY treatment. There existed renal tubule cell edema and necrosis, inflammatory cell infiltration in the CLP group, the situation was partially improved by DMY. MiR-199b-3p bound to Nrf2. Nrf2 levels were increased, TNF-α, IL-6, and KIM-1 were decreased after transfected with miR-199b-3p inhibitor, these effects were reversed when co-transfected with si-Nrf2. TNF-α, IL-6, KIM-1, and miR-199b-3p levels were increased; Nrf2, NQO-1, and HO-1 levels were decreased in the LPS + DMY + mimics-miR group. MiR-199b-3p was increased in septic AKI models, DMY might alleviate septic AKI by regulating miR-199b-3p to affect the Nrf2 pathway.

The progressive and generalized loss of skeletal muscle mass and function, also known as sarcopenia, underlies disability, increasing adverse outcomes and poor quality of life in older people. Exercise interventions are commonly recommended as the primary treatment for sarcopenia. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a vital role in regulating metabolism, mitochondrial function, and the ROS-dependent adaptations of skeletal muscle, as the response to exercise. To investigate the contribution of Nrf2 to the benefits of exercise interventions in older age, aged (∼22 month old) Nrf2 knockout (Nrf2-KO) mice and age-matched wild-type (WT) C57Bl6/J mice were randomly divided into 2 groups (sedentary or exercise group). We found that exercise interventions improved skeletal muscle function and restored the sarcopenia-like phenotype in WT mice, accompanied with the increasing mRNA level of Nrf2. While these alternations were minimal in Nrf2-KO mice after exercise. Further studies indicated that Nrf2 could increase the stability of Drp1 through deubiquitinating and promote Drp1-dependent mitochondrial fission to attenuate mitochondrial disorder. We also observed the effects of sulforaphane (SFN), a Nrf2 activator, in restoring mitochondrial function in senescent C2C12 cells and improving sarcopenia in older WT mice, which were abolished by Nrf2 deficiency. These results indicated that some benefits of exercise intervention to skeletal muscle were Nrf2 mediated, and a future work should focus on Nrf2 signaling to identify a pharmacological treatment for sarcopenia.

A novel biochar electrode Bio-Fe3O4/CF used for electroreduction of nitrate was prepared by the hydrothermal synthesis method. The results showed that the growth of spherical Fe3O4 on the surface of smooth biochar can significantly increase the nitrate reduction rate. Besides, the presence of Cl and Br in the solution could promote the conversion of NH4+ to N2, thereby regulating the element nitrogen in the solution. Mechanistic analysis showed that the interconversion of Fe (II) and Fe (III) facilitates the transfer of electrons to nitrate. This study not only provides a biochar electrode material for the efficient removal of nitrate but also simply reveals regulation of halogen in solution, which provides a particular theoretical and data basis for nitrate removal.

Paeonol exerted an effect in lung cancer, but the underlying mechanism remained vague. In this research, we assessed the effects of Paeonol and microRNA (miR)-126-5p on the viability, migration, invasion, and epithelial-mesenchymal transition (EMT) of lung cancer cells. Lung cancer cells and BEAS-2B cells were treated with Paeonol, and viability was detected by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay. The migration and invasion of lung cancer cells after treatment with Paeonol at 40 μg/mL or 80 μg/mL were detected by wound healing assay and Transwell assay, respectively. The effects of Paeonol on transforming growth factor-β1 (TGF-β1)-induced EMT and relative expressions of EMT-related proteins were determined using Western blot. The target gene of miR-126-5p and the binding sites between them were predicted by TargetScan, and confirmed using dual-luciferase reporter assay. Relative expressions of miR-126-5p, its target gene and EMT-related proteins were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Rescue assay was performed to analyze the relation between Paeonol and miR-126-5p. Paeonol down-regulated cell viability and inhibited migration, invasion and TGF-β1-induced EMT while up-regulating miR-126-5p expression in lung cancer cells as the dose increased. However, miR-126-5p inhibitor could reverse the effect of Paeonol. ZEB2 was the target gene of miR-126-5p, and silencing ZEB2 expression reversed the effects of miR-126-5p downregulation. Paeonol also regulated the expression of ZEB2 in lung cancer cells, and this regulation depends on the regulation of miR-126-5p. Paeonol inhibits human lung cancer cell viability and metastasis via the miR-126-5p/ZEB2 axis, and could be adopted as a potential agent for lung cancer treatment.

Skin fibrotic diseases, such as keloids, are mainly caused by pathologic scarring of wounds during healing and characterized by benign cutaneous overgrowths of dermal fibroblasts. Current surgical and therapeutic modalities of skin fibrosis are unsatisfactory. Pinocembrin, a natural flavonoid, has been shown to possess a vast range of pharmacological activities including antimicrobial, antioxidant, anti-inflammatory, and anti-tumor activities. In this study we explored the potential effect and mechanisms of pinocembrin on skin fibrosis in vitro and in vivo. In vitro studies indicated that pinocembrin dose-dependently suppressed proliferation, migration, and invasion of keloid fibroblasts and mouse primary dermal fibroblasts. The in vivo studies showed that pinocembrin could effectively alleviate bleomycin (BLM)-induced skin fibrosis and reduce the gross weight and fibrosis-related protein expression of keloid tissues in xenograft mice. Further mechanism studies indicated that pinocembrin could suppress TGF-β1/Smad signaling and attenuate TGF-β1-induced activation of skin fibroblasts. In conclusion, our results demonstrate the therapeutic potential of pinocembrin for skin fibrosis.

A new chromene derivative, alternapyran (1), along with three known compounds (2–4), was isolated from the Alternaria sp. ZG22 obtained from a Dasymaschalon rostratum collected from the Hainan. The structure of the new compound 1 was elucidated by NMR and mass spectroscopic data. Compounds 2 and 3 showed broad spectrum antibacterial activity against four terrestrial pathogenic bacteria.

Leukemia inhibitory factor receptor (LIFR), as a neuroregulatory cytokine receptor, generally shows a neuroprotective effect in central nervous system injuries. In this study, to understand the effect of LIFR on pathogenesis of neural tube defects, we explored spatiotemporal expression of LIFR at different stages of fetal development in normal and neural tube defect embryos. Spina bifida aperta was induced with all-trans retinoic acid on embryonic day 10 in rats, and the spatiotemporal expression of LIFR was investigated in spina bifida aperta rats and healthy rats from embryonic day 11 to 17. Real time-polymerase chain reaction and western blot assay were used to examine mRNA and protein expression of LIFR in healthy control and neural tube defect embryos. Results of the animal experiment demonstrated that expression of LIFR protein and mRNA in the spinal cords of normal rat embryos increased with embryonic development. LIFR was significantly downregulated in the spinal cords of spina bifida aperta rats compared with healthy rats from embryonic days 11 to 17. Immunohistochemical staining showed that the expression of LIFR in placenta and spinal cord in spina bifida aperta rat embryos was decreased compared with that in control embryos at embryonic day 15. Results from human embryo specimens showed that LIFR mRNA expression was significantly down-regulated in spinal cords of human fetuses with neural tube defects compared with normal controls at a gestational age of 24 to 33 weeks. The results were consistent with the down-regulation of LIFR in the animal experiments. Our study revealed spatiotemporal changes in expression of LIFR during embryonic neurulation. Thus, LIFR might play a specific role in neural tube development. All animal and human experimental procedures were approved by the Medical Ethics Committee of Shengjing Hospital of China Medical University, China (approval No. 2016PS106K) on February 25, 2016.

Objectives The knowledge that agmatine is found in the human body has existed for several years; however, its role in sepsis has not yet been studied. In the present study, we investigate the role of agmatine in the progression and treatment of sepsis. Design Clinical/laboratory investigations. Setting Medical centers/University-based research laboratory. Subjects Elective ICU patients with severe sepsis and healthy volunteers; C57BL/6 mice weighing 18-22 g. Interventions Serum agmatine level and its associations with inflammatory markers were assessed in patients with sepsis. Agmatine was administered intraperitoneally to mice before a lipopolysaccharide challenge. Human peripheral blood mononuclear cells and murine macrophages were pretreated with agmatine followed by lipopolysaccharide stimulation. Measurements and main results Serum agmatine levels were significantly decreased in patients with sepsis and lipopolysaccharide-induced mice, and correlated with Acute Physiology and Chronic Health Evaluation II score, procalcitonin, tumor necrosis factor-α, and interleukin-6 levels. In a therapeutic experiment, exogenous agmatine attenuated the cytokine production of peripheral blood mononuclear cells from patients with sepsis and healthy controls. Agmatine also exerted a significant beneficial effect in the inflammatory response and organ damage and reduced the death rate in lipopolysaccharide-induced mice. Imidazoline I2 receptor agonist 2-benzofuran-2-yl blocked the pharmacological action of agmatine; whereas, other imidazoline receptor ligands did not. Furthermore, agmatine significantly impaired the inflammatory response by inactivating nuclear factor-κB, but not protein 38 mitogen-activated protein kinase, c-Jun N-terminal kinase, extracellular signal-regulated kinase, and inducible nitric oxide synthase signaling in macrophages. Activation of imidazoline I2 receptor or knockdown of ribosomal S6 kinase 2 counteracted the effects of agmatine on phosphorylation and degradation of inhibitor of nuclear factor-κBα. Conclusions Endogenous agmatine metabolism correlated with the progression of sepsis. Supplemental exogenous agmatine could ameliorate the lipopolysaccharide-induced systemic inflammatory responses and multiple organ injuries through the imidazoline I2 receptor-ribosomal S6 kinase 2-nuclear factor-κB pathway. Agmatine could be used as both a clinical biomarker and a promising pharmaconutrient in patients with severe sepsis.

New electron-donating fused-ring cores based on tetrathienoacene were designed, with which new NIR-sensitive fused-ring electron acceptors, F8IC1 and F10IC1, were synthesized. Compared with the thieno[3,2-b]thiophene-based counterpart F6IC, F8IC1 and F10IC1 show heavily elevated HOMO and slightly elevated LUMO levels, bathochromic absorption spectra with reduced optical bandgaps, and enhanced electron mobilities. Paired with the polymer donor material PTB7-Th, the organic photovoltaic devices based on F8IC1 and F10IC1 show synchronous enhancement of open-circuit voltage, short-circuit current and fill factor. The single-junction cells based on F8IC1 and F10IC1 achieve efficiencies of 10.7% and 12.3%, respectively, surpassing those of the F6IC-based control cells (7.00%).

Based on semi-interpenetrating polymer network (semi-IPN) hydrogel films, a multiple stimuli-responsive film system composed of poly(acrylic acid) (PAA) and N,N-diethyl acrylamide (DEA), designated as PAA–PDEA semi-IPN films, was realized on a glassy carbon (GC) electrode surface with a one-step polymerization method. Rutin (RT), an electroactive probe, displayed invertible pH-, thermo- and SO42− concentration–sensitive cyclic voltammogram (CV) behaviors in the film system. This multiply sensitive electrocatalysis of RT at the PAA–PDEA films was employed to further investigate the multiple stimuli-responsive ON–OFF behaviors of RT. The scanning electron microscopy (SEM) images and control experiments showed pH-sensitive ON–OFF properties of RT, which could be ascribed to the protonated/deprotonated carboxylic (–COOH) groups of the PAA component in different pH buffers and the properties of RT itself. However, the confirmation change or phase transition of the PDEA hydrogel film between the coil and globular states led to thermo- and SO42− concentration–sensitive ON–OFF properties. According to these results, a 3-input/3-output logic gate and a 2-to-1 encoder were constructed successfully. This present system was fabricated for the first time, which may offer numerous possibilities for the design of new electrochemical drug sensors, drug-mimicking release processes and other medical applications. Furthermore, it also can contribute to the development of biomolecular or molecular computing.

The electrocatalytic oxygen reduction reaction (ORR) is a crucial part in developing high-efficiency fuel cells and metal-air batteries, which have been cherished as clean and sustainable energy conversion devices/systems to meet the ever-increasing energy demand. ORR electrocatalysts currently employed in the cathodes of fuel cells and metal-air batteries are mainly based on high-cost and scarce noble metal elements. It is thus of great importance to develop cheap and earth-abundant ORR electrocatalysts. In this aspect, redox-active transition metal hydroxides, a class of multifunctional inorganic layered materials, have been proposed as prospective candidates on account of their abundance and high ORR activities. In this article, the preparation and structural evolution of transition metal hydroxides, in particular their exfoliation into two-dimensional (2D) nanosheets, as well as compositing/integrating with catalytic active and/or conductive components to overcome the insulating nature of hydroxides in alkaline ORR, are summarized. Recent advances have demonstrated that 2D transition metal hydroxides with carefully tuned compositions and elaborately designed nanoarchitectures can achieve both high activity and high pathway selectivity, as well as excellent stability comparable to those of commercial Pt/C electrocatalysts. To realize the dream of renewable electrochemical energy conversion, new strategies and insights into rational designing of 2D hydroxide-based nanostructures with further enhanced electrocatalytic performance are still to be vigorously pursued.

Homo-junction and multi-layer structures of transition metal chalcogenide (TMD) materials provide great flexibility for band-structure engineering and designing photoelectric devices. However, the knowledge of van der Waals epitaxy growth limits the development of these heterostructures. Herein, we employed the chemical vapor deposition (CVD) growth strategy to synthesize novel WSe2 homo-junction samples with a triangular monolayer in the center and three AA stacking bilayer flakes connected to the vertexes of the monolayer. The emitted photon energy from the bilayer near the junction showed a blueshift in energy of up to 24 meV compared with bare bilayer WSe2, confirming the charge transfer effect from monolayer to bilayer WSe2. Further growth studies revealed the shape evolution from WSe2 homo-junction to bilayer. The whole homo-junction formation and evolution process cannot be explained by the traditional layer-by-layer growth mechanism. Instead, a direct bilayer growth approach is proposed to explain the bilayer formation and evolution at the vertexes of the bottom layer of WSe2. These findings suggest that the growth of bilayer TMDs is more complex than our previous understanding. This work presents deepens insight into van der Waals epitaxy growth, and thus is valuable for guiding the fabrication of novel homo-junctions for both fundamental science and optoelectronic applications.

Structure fine-tuning is effective to optimize the energy level matching and morphology in polymer solar cells (PSCs), and is important to enhance the photovoltaic performance. Here, we report a fine-tuning approach by introducing a methyl group in the 4-position of the conjugated thiophene side chains. A series of polymeric donors are synthesized based on benzo[1,2-b:4,5-b′]dithiophene (BDT) units with 4-alkyl-5-(2-ethylhexyl)thiophene conjugated side chains. Methyl, ethyl, and n-hexyl are employed as the 4-alkyl groups to afford polymers PMT49, PET52, and PHT53, respectively, and PTh37 is the control polymer without 4-alkyl groups. It is found that the introduction of a 4-alkyl group can lower the energy levels, leading to enhanced open-circuit voltage (VOC) of PSCs. PMT49 shows higher charge mobilities in blend films and more optimized morphology with smaller domain size and little decrease of domain purity than other alkyl group modified polymers. As a result, PMT49:ITIC PSCs processed from toluene exhibit a better average power conversion efficiency (PCE) of 12.0% than the PTh37 (10.6%), PET52 (9.68%) and PHT53 (7.85%) based PSCs. Furthermore, PMT50 with the 5-(2-ethylhexylthio)-4-methylthiophene side chains is synthesized. PMT50:Y6(BO) PSCs exhibit an impressive average PCE of 15.1% when processed from 1,2,4-trimethylbenzene, significantly higher than the devices processed from PEHTT:Y6(BO) without methyl functionalization (12.8%). Our studies suggest that methyl functionalization on conjugated side chains is a simple but effective fine-tuning strategy to develop conjugated polymers for high performance PSCs processed from non-chlorinated solvents.

Cyclic polymers have outperformed their linear analogues for controlled release applications in terms of greater stability and better therapeutic efficiency due to the endless chain topology. However, to our knowledge, there have been thus far only a few examples of the fabrication of pH-sensitive cyclic polymers for drug delivery applications. To further improve the colloidal stability of the previously synthesized cyclic poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) for drug delivery applications via a facile yet efficient approach, it will be useful and straightforward to incorporate a hydrophilic monomer for copolymerization with DMAEMA. For this purpose, we reported in this study the preparation of pH-sensitive cyclic statistical copolymers, P(OEGMA-st-DMAEMA)s, with two different compositions by atom transfer radical polymerization (ATRP) of oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA) and DMAEMA and subsequent “intra-chain” click cyclization of the α-alkyne-ω-azide linear precursor. A further comparison study on the micelle stability revealed that the spherical micelles self-assembled from c-P(OEGMA4-st-DMAEMA38) (C) with both smaller hydrodynamic size than that of the micelles of the linear analogue, l-P(OEGMA4-st-DMAEMA38) (L), and greater salt stability than that of the micelles of c-P(OEGMA8-st-DMAEMA38) were screened to be the optimal micelle construct for drug delivery applications. Flow cytometry (FCM) analysis confirmed greater cellular uptake efficiency of doxorubicin (DOX)-loaded C (C@DOX) micelles than that of the L (L@DOX) ones. More importantly, the C@DOX micelles showed comparable in vitro cytotoxicity against the cancer cell line (HeLa cells) but lower in vitro cytotoxicity against the normal cell line (HUVEC cells) relative to the L@DOX formulation after 72 h of incubation. Therefore, this study not only developed a facile approach to improve the colloidal stability of a cyclic polycation, but also presented a pH-sensitive cyclic copolymer-based nanoplatform with great potential for anticancer drug delivery.

Fabrication of cyclic graft (cg) copolymer-based polymeric prodrugs by conjugation of drug molecules to cg copolymers via a dynamic covalent bond capable of responding to biorelevant signals integrates simultaneously the merits of cg copolymers and polymeric prodrugs for enhanced stability of nanocarriers and precise modulation of drug release kinetics. To completely eliminate the compromised drug conjugation efficiency due to the steric hindrance of hydrophilic grafts, it will be useful to develop cg polymeric prodrugs with heterogeneous grafts composed of hydrophilic polymers and drug species, respectively. For this purpose, we reported in this study the synthesis of cyclic graft polymeric prodrugs with heterogeneous grafts of hydrophilic oligo (ethylene glycol) (OEG) and reducibly conjugated camptothecin (CPT), cg-poly(oligo(ethylene glycol) monomethyl ether methacrylate)-b-poly((2-hydroxyethyl methacrylate)-disulfide link-camptothecin) (cg-P(OEGMA)-b-P(HEMA-SS-CPT), cg-prodrugs), via an integrated strategy of a previously reported diblock copolymer-based template and post-polymerization intermolecular click conjugation of a reducible CPT prodrug. The micelles self-assembled from cg-prodrugs on one hand had sufficient salt stability due to the branched cg structure, and on the other hand showed a reduction-triggered cleavage of the disulfide link for a promoted CPT release. Most importantly, we uncovered two interesting phenomena of the cg-based polymeric prodrugs as delivery vehicles: (i) the dimensions of both self-assemblies formed by the cg and bottlegraft (bg) polymers depend substantially on the molecular size of the cg and bg polymers likely due to the steric hindrance of the grafted structures of the cg and bg molecules and relatively low aggregation number of the self-assembled structures, and (ii) cg-prodrug-based micelles exhibited greater in vitro cytotoxicity against cancer cells despite the lower drug loading content (DLC) than the bg-based analogues, which results primarily from the faster reduction-triggered degradation and drug release as well as the greater cellular uptake efficiency of the former micelle prodrugs. Taken together, the developed cg-prodrugs provide great potential for chemotherapy, and the aforementioned interesting results will definitely inspire more upcoming studies on the future design and development of novel cg polymers for biomedical applications.

Conjugation of folic acid (FA) onto the surface of nanocarriers for active targeting is the mainstream strategy to improve the targeting efficiency of delivery vehicles for enhanced anticancer drug delivery; however, this strategy suffers from the fast clearance of nanocarriers caused by an immunological response and the nonspecific cellular uptake of nanocarriers compromising therapeutic efficiency and causing serious side effects. To address this dilemma, a dual-functional sheddable monomethoxypolyethylene glycol (mPEG) stealth component for both protection of the FA targeting ligand and extracellular stabilization of the micelles was incorporated into the polymeric micelles to realize simultaneous tumor-triggered targeting and intracellular micelle destabilization for enhanced cellular uptake and drug release. Specifically, the mPEG stealth component containing a tumor acidic pH-cleavable hydrazone bond was linked to an FA-conjugated amphiphilic block-statistical copolymer, FA-poly(oligo(ethylene glycol)monomethyl ether methacrylate)-st-poly(2-hydroxyethyl methacrylate-g-lactide) (P(OEGMA300)-st-P(HEMA-g-LA)) via highly efficient click coupling. The deshielding of the mPEG stealth component at the weakly acidic pH of the tumor site can expose the FA targeting ligand that is shielded under physiological conditions for active targeting, and trigger the destabilization of the self-assembled micelles for accelerated drug release. Meanwhile, reducibly conjugating the FA targeting ligand via a disulfide bond can further promote the targeting efficiency of the micelles by continuous folate receptor (FR)-mediated endocytosis. A panel of block-statistical copolymers with three different hydrophilic weight fractions was synthesized to investigate the structure–property relationship of this micelle construct. The optimized micelle formulation based on mPEG(FA)-P(OEGMA300)4-st-P(HEMA-g-LA)4 is relatively stable at pH 7.4 with a hydrodynamic diameter (Dh) of 41 nm, and the intracellular simultaneous cleavage of the disulfide links and hydrazone bonds led to significantly promoted destabilization of the drug-loaded micelles for promoted drug release. Therefore, the adoption of a sheddable mPEG stealth component with dual functionalities for greater cellular uptake and faster drug release of micelles provides a powerful means of enhanced anticancer drug delivery.

Four new main-chain-twisted acceptor–donor–acceptor-type (A–D–A) non-fullerene acceptors (i-mO-4F, i-mO-4Cl, i-pO-4F, and i-pO-4Cl) were designed and synthesized, featuring the introduction of meta-hexyloxy-phenyl and para-hexyloxy-phenyl side-chains in the fused-ring core as well as 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile and 2-(5,6-dichlorine-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile as the end-capping groups. All four small molecules exhibited broad absorption spectra in the range of 300 nm to 820 nm with a corresponding small optical bandgap of 1.55 eV (i-mO-4F), 1.53 eV (i-mO-4Cl), 1.52 eV (i-pO-4F), and 1.48 eV (i-pO-4Cl), which ensured total complementary absorption with a wide bandgap polymer donor material (PBDB-T). Although i-mO-4Cl possessed a finely bathochromic-shifted absorption spectrum, its poor morphology with PBDB-T in the blend films led to a low power conversion efficiency (PCE) of 7.41%. In contrast, the optimal PBDB-T:i-mO-4F-, PBDB-T:i-pO-4F-, and PBDB-T:i-pO-4Cl-based devices achieved promising PCEs of 14.02%, 13.47%, and 10.98%, respectively. The obtained significantly different results for these two types of NFAs, on the one hand, demonstrate the synergistic effect of the hexyloxy-phenyl side-chain modification and non-planar main-chain strategy to construct highly efficient non-fullerene acceptors for polymer solar cells, and on the other hand, reveal the influence of the fluorinated and chlorinated end-groups on the morphologies and performances of the resultant main-chain-twisted NFAs.

Core engineering of perylene diimide (PDI)-based small molecular acceptors has played a critical role in boosting the device performances in the field of organic solar cells (OSCs). In this work, two regio-isomeric PDI-based acceptors (named oCP-FPDI4 and pCP-FPDI4) based on a novel [2.2]paracyclophane core were designed and synthesized. Due to the subtle variations in the functionalization positions on the [2.2]paracyclophane moiety, the two PDI acceptors exhibit different molecular geometries and absorption properties. When blended with a donor polymer named P3TEA, oCP-FPDI4 and pCP-FPDI4 showed dramatic differences in photovoltaic performances (2.42% vs. 9.06%). In-depth studies on the nano-scale morphology of the respective blend films revealed that the P3TEA:pCP-FPDI4 blend exhibited suitable phase segregation, thus contributing to better charge dissociation and less charge recombination. The marked variations in photovoltaic performances between oCP-FPDI4 and pCP-FPDI4 highlight the importance of regulating the spatial orientations in the design of PDI-based acceptors using cyclophane derivatives.