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Ganoderma tsugae is well known as a medicinal mushroom in China and many Asian countries, while its fermentation technique and corresponding pharmacological activity are rarely reported. In this study, a wild G. tsugae strain (G42) with high triterpenoid content was screened from nine strains by rice solid-state fermentation, and 53.86 mg/g triterpenoids could be produced under optimized conditions; that is, inoculation amount 20%, fermentation temperature 27 °C, and culture time 45 days. The hepatoprotective activity of G42 ethanol extract was evaluated by CCl4-induced liver injury in mice, in which changes in the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), oxidation-related factors, and inflammatory cytokines in serum or liver samples demonstrated the therapeutic effect. In addition, the ethanol extract of G42 reduced the incidence of necrosis and inflammatory infiltration, and decreased protein expression levels of phosphor-nuclear factor-κB (NF-κB), interleukin-Iβ (IL-1β), and nuclear factor erythroid-2-related factor 2 (NRF2). The chemical composition of the ethanol extract was analyzed by high-resolution mass spectrometry and molecular networking. Three main triterpenoids, namely platycodigenin, cucurbitacin IIb, and ganolecidic acid B were identified. This work provided an optimized fermentation method for G. tsugae, and demonstrated that its fermentation extract might be developed as a functional food with a hepatoprotective effect. [ABSTRACT FROM AUTHOR]

Low-density polyethylene single-polymer composites (SPCs) reinforced with sandwiched ultrahigh-molecular-weight polyethylene woven fabric were prepared by insert injection molding. The process combines aesthetic and processing advantages. A processing temperature window (135–155°C) of a very short cycle time (less than 30 s) could be realized. The mechanical properties and morphologies of the samples were evaluated. The results suggested that the polyethylene SPCs were prepared successfully with concurrent increases in flexural strength (∼57%), tensile strength (∼164%), and impact strength (∼69%). The effects of different processing parameters including the nozzle temperature, injection pressure, injection speed, and the holding time were discussed. Numerical simulation results were used in the analysis. [ABSTRACT FROM AUTHOR]

In a recent work published by Haugan et al. (ACS Macro Lett., 2018, 7, 525–530.), the linear viscoelastic behaviors of a series of random graft polymers as a function of grafting density (Z) and backbone degree of polymerization ( n b b ) for a constant side chain degree of polymerization was investigated. The results were interpreted to imply that as Z increases the backbone concentration decreases and the distance between entanglements increases (the number of backbone degree of polymerization between entanglements ( n e , b b ) increases from 55 for Z = 0 to 550 for Z = 1.). One evidence of entanglement formation was that the zero-shear rate viscosity ( η 0 ) showed a departure from Rouse scaling to reptation scaling as molecular weight increased. However, the values of η 0 from the dynamic modulus measurements used in that work were, for multiple cases, underestimated because the Newtonian plateau at low frequencies was not reached. In the present work, the rheological data for these graft polymers are reanalyzed, some samples are measured again, and the resulting new estimates of the zero shear-rate viscosity ( η 0 ) lead to changes in the interpretation of the results. Furthermore, we calculated the retardation spectra (L (τ)) for the samples, showing that the entanglement behavior of these systems is similar to but not identical to the behavior of the linear chain polymer. The results show that in the transition from Rouse-like to entangled behavior η 0 exhibits a M w 3.4 dependence on molecular weight rather than the M w 3 previously reported for these graft polymers. By plotting η 0 as a function of n b b at different Z , the data collapse into two families of behavior and the critical grafting density Z is approximately 0.2–0.25. The onset of entanglements as n b b or M w increases at fixed Z is confirmed from the retardation spectrum, However, the progressive development of the retardation spectrum for these side chain diluted systems differs from that of entangled polymer solutions in that the spectrum first broadens at short times before splitting into two distinct peaks, while for solutions the appearance and shifting to longer times of a second peak occur more abruptly. Image 1 • Bottle brush rheology follows linear chain viscosity-molecular weight dependence. • η 0 determined as a function of backbone DP n b b at different grafting densities Z • η 0 shows distinct behaviors at low grafting density and high grafting density. • When Z ≤ 0.2, η 0 follows a power law dependence of 3.4 on n b b • When Z ≥ 0.25, η 0 follows a power law on n b b that changes from 1 to 3.4 [ABSTRACT FROM AUTHOR]

[Display omitted] In this paper we report the synthesis and analysis of cyclic polydisulfides, their redox depolymerization as well as their interaction with carbon black. Cyclic poly(3,6-dioxa-1,8-octanedithiol)s (pDODT) were synthesized by Reversible Radical Recombination Polymerization (R3P). R3P is a scalable "green" polymerization process using triethylamine (TEA), H 2 O 2 and air for the polymerization of dithiol monomers. pDODTs were synthesized in 5 and 20 g batches. The effect of peroxide concentration (3, 5, 10, 20, 30 %) was investigated. It was found that the molecular weights increased exponentially with increasing peroxide concentrations. At 30 % peroxide concentration pDODTs with M n up to 400,000 g/mol and polydispersity of 2 were obtained. 700 and 800 MHz NMR were used for investigating the chemical structure of the polymers. The absence of thiol end group signals in polymers made with > 10 wt % H 2 O 2 and M n < 100,000 g/mol, including a sample of a fractionated polymer with starting M n = 600,000 g/mol, verified cyclic structures. Dithiothreitol reduced the polymers to monomer and a small percentage of oligomers. Carbon black was shown to increase the moduli of high molecular weight pDODTs. Swelling tests in chloroform showed that polymers made with 20 and 30 w% peroxide swelled 14 and 10 times of their starting weight without dissolving, indicating chemical interaction between the polymers and carbon black. Further analysis of these interesting elastomers, available at the 20 g scale, is in progress. [ABSTRACT FROM AUTHOR]

This paper investigates liquid chromatography at critical condition (LCCC) for polymer analysis. Based on controversial claims on the separation of cyclic polymers from linear analogues in the literature, the efficiency of LCCC for separation and purity analysis is questioned. Polyisobutylene (PIB) and poly(3,6-dioxa-1,8-octanedithiols) (polyDODT) were used for the study. The structure of low molecular weight cyclic and linear polyDODT was demonstrated by MALDI-ToF. NMR did not show the presence of thiol end groups in higher molecular weight PIB-disulfide and polyDODT samples, so they were considered cyclic polymers. When a low molecular weight polyDODT oligomer with only traces of cycles, as demonstrated by MALDI-ToF, was mixed with an M n = 27 K g/mol cyclic sample, LCCC did not detect the presence of linear oligomers at 6 wt%. Based on the data presented here, it can be concluded that the LCCC method is not capable of measuring <6 wt% linear contamination so earlier claims for cyclic polystyrene (PS) samples purified by LCCC having <3% linear contaminants are questioned. Unlabelled Image • Liquid chromatography at critical condition (LCCC) – capabilities and limitations • Investigation of poly(3,6-dioxa-1,8-octanedithiol) (polyDODT) and polyisobutylene-disulfide (PIB-SS) • Demonstration of linear and cyclic polyDODT structure by NMR and MALDI-ToF • Demonstration of cyclic PIB-SS by NMR • Limitations: solubility of low and high molecular weight samples; detection limit of <6 wt% [ABSTRACT FROM AUTHOR]