The preparation of poly(L-lactic acid) (PLLA) foam with well defined cell structure and high heat resistance is critical to broaden its applications.In this study, the stereocomplex crystallites (SC) with higher melting point and heat stability was introduced into PLLA foam by melt blending the PLLA with different amount of poly(D-lactic acid) (PDLA). The crystal structure of pure PLLA and PLLA/PDLA blends formed during blending and molding process was compared. It was found that no obvious crystallization was detected in pure PLLA, while SC formed in PLLA/PDLA blends. Crystal structure and morphology evolution of PLLA and PLLA/PDLA during CO 2 saturation and foaming process were investigated by combination of DSC, WAXD, FTIR and SEM techniques. The results suggested SC had higher melting peak, higher thermal stability, and smaller crystal domain size in relative to the homocrystal of PLLA, and it did not further develop with the CO 2 saturation and the foaming processes, while the CO 2 saturation induced the formation of the mesomorphic structure in PLLA and PLLA/PDLA blends. The mesomorphic structure transformed into more stable α form in the following foaming process. The resultant PLLA/PDLA foam exhibited significant and concurrent increase in cell density and cell structure uniformity relative to PLLA foam. The heat resistance measurement presented that thus prepared PLLA/PDLA foams had better heat resistance than PLLA foam, which was attributed to the higher melting point, higher heat stability and the higher cell nucleation ability of SC in PLLA/PDLA foams.

Mycoplasma pneumoniae, an obligate parasitic pathogen without cell wall, can cause severe upper and lower respiratory tract symptoms. It is the pathogen of human bronchitis and walking pneumonia, and named community-acquired pneumonia. In addition to severe respiratory symptoms, there are clinical extrapulmonary manifestations in the skin, brain, kidney, musculoskeletal, digestive system, and even blood system after M. pneumoniae infection. Hereby, we comprehensively summarized and reviewed the intrapulmonary and extrapulmonary pathogenesis of M. pneumoniae infection. The pathogenesis of related respiratory symptoms caused by M. pneumoniae is mainly adhesion damage, direct damage including nutrient predation, invasion and toxin, cytokine induced inflammation damage and immune evasion effect. The pathogenesis of extrapulmonary manifestations includes direct damage mediated by invasion and inflammatory factors, indirect damage caused by host immune response, and vascular occlusion. The intrapulmonary and extrapulmonary pathogenic mechanisms of M. pneumoniae infection are independent and interrelated, and have certain commonalities. In fact, the pathogenic mechanisms of M. pneumoniae are complicated, and the specific content is still not completely clear, further researches are necessary for determining the detailed pathogenesis of M. pneumoniae. This review can provide certain guidance for the effective prevention and treatment of M. pneumoniae infection. Abbreviations CARDSCommunity-acquired respiratory distress syndrome toxin GlpO L-α-glycerophosphate oxidase KATP channels ATP-sensitive K + channels ROS Reactive oxygen species LAMPS Lipid-associated membrane proteins HDAC 5 Histone deacetylase 5 IbpM Immunoglobulin binding protein of Mycoplasma NET Neutrophil extracellular traps EF-Tu Elongation factor thermo unstable MpEPDs Mycoplasma pneumoniae-related extrapulmonary diseases * Weimin Xie

The surface functionalization of cellulose nanocrystals (CNCs) is of significant importance for promoting its diverse applications. However, the efficient strategy reported so far for cation functionalization of CNCs remains limited owing to the electrostatic attraction between cationic modifiers and electronegative CNCs. Herein, a cationized CNC (CNC-LA-IL) has been successfully prepared in aqueous media by grafting the [VBIm]­[BF4], a kind of ionic liquid (IL), on the surface of a sulfated CNC using lactic acid (LA) as a linker molecule. This surface functionalization not only converts the negative charge of CNC suspensions to a positive charge (zeta potential reversed from −35 to +40 mV) but also leads to enhanced thermal stability and redispersibility of the dried CNC. To examine the reinforcing effect of IL-modified CNCs, poly­(vinyl alcohol) (PVA)/CNC-LA-IL nanocomposite films were further prepared by the solution casting method. To one’s surprise, the as-prepared PVA/CNC-LA-IL films exhibit extraordinary improvement in both the tensile strength (92%) and the toughness (166%) with only a 0.3 wt % CNC loading. This study provides a green and facile method to achieve ionic liquids grafted CNCs for high-performance nanocomposites.

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