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The intrinsic drawback of slow crystallization rate of poly(l-lactide) (PLLA) inevitably deteriorates its final properties of the molded articles. In this work, we proposed a new strategy towards poly(l-lactide) with enhanced crystallization rate by ring opening polymerization (ROP) of l-lactide (l-LA) catalyzed by biocompatible zinc salts of amino acids. For the first time we developed a one-pot facile method of zinc salts of amino acids acting dual roles of catalysis of l-LA polymerization and in situ nucleation of the as-prepared PLLA. Nine zinc salts of different amino acids, including three kinds of amino acids ligands (alanine, phenylalanine, and proline) with l/d-enantiomers and their equimolar racemic mixtures, were first prepared and tested as catalysts of l-LA polymerization. A partial racemization was observed for zinc salts of amino acids whereas no racemization was detected for the reference stannous octoate. The polymerization mechanism study showed that the interaction of zinc salts of amino acids and benzyl alcohol forms the actual initiator for l-LA polymerization. Isothermal crystallization kinetics analysis showed that the residual zinc salts of amino acids exhibited a significant nucleation effect on PLLA, evidenced by the promotion of the crystallization rate, depending on the amino acid ligand and its configuration. Meanwhile, the residual zinc salts of amino acids did not compromise the thermal stability of the pristine PLLA. [ABSTRACT FROM AUTHOR]

• Zinc salts of amino acids were developed as a new class of biocompatible NAs for PLLA. • The nucleation mechanism was explained by epitaxial nucleation based on lattice matching. • The difference in nucleation ability was attributed to the size and uniformity of NA particles. • Zinc d -phenylalaninate is a promising NA as bioresource additive of PLLA. The slow crystallization speed of poly(l -lactide) (PLLA) during practical processing results in the low degree of crystallinity and thus poor heat resistance of the molded articles, which prevents the wider applications of PLLA. The additive of biocompatible nucleating agents is one of the most effective means to promote the crystallization of PLLA, which synchronously preserves the bio-advantages of PLLA materials for biomedical and food applications. In this work, a series of zinc salts of amino acids, including nine kinds of l -amino acids and six types of d - or dl -configuration amino acids, was prepared and evaluated as nucleating agents (NAs) for PLLA. The nucleation effect of NAs was compared in terms of the nonisothermal melt crystallization peak temperature of PLLA with 1 wt% loading of NAs under a cooling rate of 10 °C/min. It was found that the nucleation effect of the zinc salts of amino acids depends on the ligand and its configuration. The nucleation mechanism and the difference of nucleation ability were also discussed and explained. Among these tested NAs, zinc d -phenylalaninate (Zn(d -Phe) 2) is the most effective one, which is comparable to the current outstanding NAs, evidenced by the crystallization peak temperature at 130 °C accompanying with the crystallization enthalpy up to 48 J/g. It is expected that Zn(d -Phe) 2 is a promising nucleating agent providing high nucleation activity in injection molding and extrusion processing of PLLA articles. [ABSTRACT FROM AUTHOR]

Ring opening copolymerization of ethylene brassylate (EB) and δ-valerolactone (δ-VL) with various feeding ratios catalyzed by triphenyl bismuth was performed to prepare poly(ethylene brassylate-co-δ-valerolactone) copolyesters. The reactivity ratios of EB and δ-VL were firstly determined to be r EB = 0.64 and r VL = 2.54 , respectively. Then the copolymerization kinetics was traced and microstructure analysis showed that the chain structure of copolyesters were rearranged towards complete random as a consequence of transesterification reaction. The resulting random copolymers were found to cocrystallize to exhibit isodimorphism phenomenon with a pseudo-eutectic point of melting temperatures and lattice spacings at 80 mol% δ-VL units. Moreover, the variation of the lattice spacings confirmed that the comonomer units have better miscibility in the case of incorporation of shorter units into longer unit crystal than the opposite case. Finally, the continuously tunable mechanical properties of these copolyesters showed a similar pseudo-eutectic behavior at the same eutectic point of isodimorphism, which indicated that the correlation between isodimorphism and mechanical properties depending on composition is highly significant. [ABSTRACT FROM AUTHOR]

A rapid expansion of HFMD with enterovirus 71 infection outbreaks has occurred and caused deaths in recent years in China, but no vaccine or antiviral drug is currently available for EV71 infection. This study aims to provide treatment programs for HFMD patients. We conducted a randomized, double-blind, controlled trial and evaluated clinical efficacy of therapy with rHuIFN-α1b in HFMD patients with EV71 infection. There were statistical differences in outcomes including the fever clearance time, healing time of typical skin or oral mucosa lesions, and EV71 viral load of the HFMD patients among ultrasonic aerosol inhalation group, intramuscular injection group and control group. rHuIFN-α1b therapy reduced the fever clearance time, healing time of typical skin or oral mucosa lesions, and EV71 viral load in children with HFMD. Trial Registration: Chinese Clinical Trial Registry [ABSTRACT FROM AUTHOR]

Background: Hand-food-mouth disease (HFMD) cases can be fatal. These cases develop rapidly, and it is important to predict the severity of HFMD from mild to fatal and to identify risk factors for mild HFMD. The objective of this study was to correlate the levels of serum inflammatory cytokines with HFMD severity. Methods: This study was designed as a nested serial case-control study. The data collected included general information, clinical symptoms and signs, laboratory findings and serum cytokine levels. Results: The levels of IL-4, IL-6, IL-10, TNF-α and IFN-γ in patients with severe HFMD were significantly higher than in mild patients during the 2nd to 5th day after disease onset. The levels of IL-4, IL-6, IL-10 and IFN-γ increased from the 2nd day to the 4th day and later decreased. The levels of TNF-α were high on the first two days and subsequently decreased. The changes of IL-10, TNF-α and IFN-γ in the controls were similar for all cases. The levels of IL-4, IL-6 and IL-17 in the controls were not significantly different with the progression of HFMD. Conclusions: Our findings indicate that the IL-4, IL-6, IL-10, TNF-α and IFN-γ levels correlate with HFMD severity. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via the original article. [ABSTRACT FROM AUTHOR]