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Self-healing of damage is a common phenomenon in organisms but is hardly ever encountered in rigid polymer materials. For next-generation electricals and electronics, it is crucial to accurately mimic organisms to detect and heal mechanical/electrical damage. Herein, disulfide bond exchange is designed to introduce the self-healing ability in a copolymerized polyimide (copolyimide). A copolyimide insulation film with two diamine monomers is successfully prepared, which also possesses good self-healing ability after being mechanical/electrical damaged. Furthermore, the self-healing copolyimide film still maintains its good Young's modulus (E) >4 GPa, high thermal stability with glass transition temperature (Tg) >190 °C, and excellent insulation property with breakdown strength (Eb) >300 kV mm−1. The combination of the simple copolymerization and unique self-healing ability is suitable for high Tg polyimide to make this an ideal method for insulation field.

Dielectric polyimides (PIs) are ubiquitous as insulation in electrical power systems and electronic devices. Generally, dynamic polyimide is required to solve irreversible failure processes of electrical or mechanical damage, for example, under high temperature, pressure, and field strength. The challenge lies in the design of the molecular structure of rigid polyimide to achieve dynamic reversibility. Herein, a low-molecular-weight polyimide gene unit is designed to crosslink with polyimide ligase to prepare the smart film. Interestingly, due to the variability of gene unit and ligase combinations, the polyimide films combining hardness with softness are designed into three forms via a "Mimosa-like" bionic strategy to adapt to different application scenarios. Meanwhile, the films have good degradation efficiency, excellent recyclability, and can be self-healable, which makes them reuse. Clearly, the films can be used in the preparation of ultrafast sensors with a response time ≈0.15 s and the application of corona-resistant films with 100% recovery. Furthermore, the construction of polyimide and carbon-fiber-reinforced composites (CFRCs) has been verified to apply to the worse environment. Nicely, the composites have the property of multiple cycles and the non-destructive recycle rate of carbon fiber (CF) is as high as 100%. The design idea of preparing high-strength dynamic polyimide by crosslinking simple polyimide gene unit with ligase could provide a good foundation and a clear case for the sustainable development of electrical and electronic polyimides, from the perspective of Mimosa bionics.

A highly stereoselective cascade Michael/alkylation process has been established to construct 2-trifluoromethylated and 2-difluoromethylated dihydrofurans from readily available starting materials. In the presence of a bifunctional squaramide, the annulation approach proceeded smoothly to afford the desired fluorinated dihydrofurans in 59–99% isolated yields with 82–96% ee and 8 : 1–>20 : 1 dr. This catalytic strategy was well compatible with various structurally distinct β,β-bromonitrostyrenes and fluorinated acetoacetates. Profound synthetic manipulation could be performed on the resulting products.

A highly enantioselective (84–97% ee) cascade Michael/acyl transfer reaction of α-nitroketones to a wide range of 2-hydroxychalcones was established in the presence of a bifunctional squaramide. Although aliphatic α-nitroketones were revealed to be a class of challenging substrates with unsatisfactory reactivity or enantioselectivity by previous reports, good isolated yields and excellent enantiopurities have been achieved via our catalytic protocol. γ-Nitroketones created by this new methodology were versatile building blocks possessing profound further synthetic utility.

Although working memory (WM) deficits are well-recognized core features of schizophrenia, the underlying pathophysiological substrates of impairment in early psychosis before medication remain unclear. One possibility is that deficits in selective attention contribute to WM impairment.EEG was acquired from 25 first-episode drug-naive schizophrenia patients and 26 matched controls while they performed a WM task.Compared with controls, schizophrenia patients showed a deficit in WM capacity in both behavioral and electrophysiological measures. Notably, the increased parieto-occipital pre-encoding stimulus alpha power in patients with schizophrenia predicted their subsequent reduced N2pc and symptom severity, whereas this relationship was absent in controls. Moreover, lacking load effect in neural activities predicted the serious impairment in behavior for schizophrenia.This pilot study provides preliminary evidence that the lack of load effect in neural activities may serve as potential underlying mechanisms for the impaired selective attention and WM capacity in schizophrenia. Our results emphasize the importance of pre-encoding stimulus alpha power in first-episode drug-naive schizophrenia.These findings provide a neurophysiological correlate for the subjective reports of working memory deficits in schizophrenia and indicate the potential effective targets for clinical intervention.

Polyimide (PI) film is considered to be an ideal packaging material due to its excellent comprehensive properties. However, the traditional PI has a relatively high dielectric permittivity ( $k=3.0\sim 3.4$ ), which cannot meet the current requirements in the field of microelectronic packaging ( $k ). In this work, Tris(4-aminophenyl) amine (TPA) was used the cross-linking agent to combine with biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA) and 1,4-Bis(4-amino-2-trifluoromethylphenoxy) benzene (6FAPB) by in-situ polymerization for the purpose of obtaining cross-linked low-dielectric polyimide. And the influences of cross-linking agent ratio on the comprehensive properties of PI were studied. The results showed that under a certain loading of TPA, the dielectric permittivity of the PI gradually decreased with the incremental crosslinking agent content. When the molar ratios of amino groups in TPA and 6FAPB was 1:9, the dielectric properties of the cross-linked PI can be minimized, with the lowest value of 1.86 (107 Hz). In addition, the obtained cross-linked polyimide had good thermal stability. It has broad development prospects in the field of microelectronic packaging and integrated circuits in the future.

A stereoselective annulation protocol was developed to construct dihydrofuranoindoles from readily available starting materials. In the presence of a bifunctional squaramide, the Friedel-Crafts alkylation/annulation cascade process occurred smoothly to provide dihydrofuranoindoles in 26-95% isolated yields exclusively as

As the miniaturization of electronic appliances and microprocessors progresses, low-permittivity interlayer materials are becoming increasingly important for their suppression of electronic crosstalk, signal propagation delay and loss, and so forth. Herein, a kind of copolyimide (CPI) film with a “fluorene” rigid conjugated structure was prepared successfully. By introducing 9,9-Bis(3-fluoro-4-aminophenyl) fluorene as the rigid conjugated structure monomer, a series of CPI films with different molecular weights were fabricated by in situ polymerization, which not only achieved the reduction of permittivity but also maintained excellent thermodynamic stability. Moreover, the hydrophobicity of the CPI film was also improved with the increasing conjugated structure fraction. The lowest permittivity reached 2.53 at 106 Hz, while the thermal decomposition temperature (Td5%) was up to 530 °C, and the tensile strength was ≥ 96 MPa. Thus, the CPI films are potential dielectric materials for microelectronic and insulation applications.

The physicochemical properties and antioxidant activities of two fucosylated chondroitin sulfate (ACP and HOP) isolated from sea cucumber Acaudina molpadioidea and Holothuria nobilis respectively were detected in this study. Their SEM and AFM images, conformation based on circular dichroism spectroscopy, specific optical rotation, intrinsic viscosity, and antioxidant activities were first determined. The SEM and AFM images demonstrated differences in the three-dimensional morphological features of the two polysaccharides. The CD results revealed the conformation variation of the two polysaccharides after thermal, acid and alkali treatments. The specific rotations of ACP and HOP were −46° and −22° respectively, and the intrinsic viscosity of ACP and HOP was 145.52 ml/g and 7.30 ml/g respectively. The antioxidant assay showed that ACP and HOP both exhibited moderate antioxidant activities against DPPH, hydroxyl, and superoxide radicals in a dose-dependent manner. Our study provides basic data for understanding the antioxidant activities of animals and exploring potential antioxidant from sea cucumber. The findings in this study also provide the basis on researching the relationship between antioxidant activities and physicochemical properties of FucCS.

The goal of our paper is to improve the accuracy of stock return forecasts by combining new technical indicators and a new two-step economic constraint forecasting model. Empirical results indicate the stock return forecasts generated by new technical indicators and new economic constraint forecasting model is statistically and economically significant both in-sample and out-of-sample prediction performance. In addition, the prediction performance of new technical indicators and new economic constraint forecasting model is robust for some extension and robustness analysis.

In this study, a sulfated polysaccharide with a high molecular weight was isolated from sea cucumber Holothuria nobilis. It is a fucosylated chondroitin sulfate and being named as HOP. We investigated the effects of several processing variables on the oxidative degradation of HOP using fractional factorial design (FFD) and central composite design (CCD). Moreover, the conditions of the hydroxyl free radical-induced degradation were optimized using response surface methodology (RSM). Our data showed that R ( H 2 O 2 – HOP ) , reaction pH and H2O2 flow rate could significantly (P R ( H 2 O 2 – HOP ) of 0.53; reaction pH of 6.91; H2O2 flow rate of 0.40 mL/min; reaction time of 2 h; reaction temperature of 30 °C; and HOP concentration of 4 mg/mL. Under these optimum conditions, the DH of HOP was 94.173 ± 0.232 (%), which well matched the value (94.152%) predicted by the RSM model. The preliminary structural characterization of o-HOP was analyzed. The results showed that o-HOP consisted of β- d -glucuronic acid, β- d -N-acetyl-galactosamine, α- l -fucose and sulfate groups. The specific rotation of o-HOP was -43.2°. Furthermore, the sulfation patterns of fucose residues in o-HOP were 2,4-O-disulfated fucose, 3-O-sulfated fucose, 4-O-sulfated fucose and non-sulfated fucose, which were consistent with HOP. In addition, we found that the in vitro antitumor activity of the degraded HOP fraction (o-HOP) was higher than that of HOP against human gastric carinoma SGC-7901 cells.

The purpose of this paper is to analyze whether the fluctuations of RMB/USD exchange rate can predict the Chinese industry return volatilities during post-financial crisis period. Our in-sample results show there is significant Granger causality from RMB/USD exchange rate fluctuations to China’s industry return volatilities. The out-of-sample results also indicate the RMB/USD exchange rate fluctuations extracts significantly useful information from the predictors. Further analysis about the energy industry shows that simple linear regression is sufficient for capturing predictive relationships between RMB/USD exchange rate fluctuations and energy industry volatility.

In this study, we isolated two fucosylated polysaccharide sulfates (ACP and HOP) from sea cucumber Acaudina molpadioidea and Holothuria nobilis, with an average molecular weight of 90.8 and 135.8 kDa, respectively. We investigated and compared their anticoagulant activities through anticoagulant assay. Our data showed that both polysaccharides possessed good anticoagulant activity, but HOP's activity was higher than that of ACP. Due to the different anticoagulant activities of ACP and HOP, we compared the preliminary structural characterizations of these two sulfated polysaccharides, and found that both ACP and HOP consisted of β- d -glucuronic acid, β- d -N-acetyl-galactosamine, α- l -fucose and sulfate groups. ACP and HOP had almost identical ratios of glucuronic acid, N-acetyl-galactosamine and fucose. However, the sulfate contents and sulfation patterns of fucose residues of ACP and HOP were obviously different. There were 4-O-sulfated fucose, 3,4-O-disulfated fucose and 2,4-O-disulfated fucose in ACP, but only 3-O-sulfated fucose and 2,4-O-disulfated fucose were present in HOP. Therefore, their distinct anticoagulant activities might be due to the different sulfate contents and sulfation patterns of their fucose residues.