Liposome-recruited activity of oxidized and fragmented superoxide dismutase

The peptide fragment of H2O2-treated Cu,Zn-superoxide dismutase (SOD) was found to be reactivated with liposomes prepared by 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). The fragmentation of SOD was observed by 2 mM H2O2 treatment as well as by SOD inactivation and the loss of an alpha-helix in the neighborhood of its activity center. The H2O2-treated SOD, which lost its activity at different incubation times, was dramatically reactivated only by adding POPC liposomes, resulting in 1.3-2.8 times higher enzymatic activity. The ultrafiltration analysis of H2O2-treated SOD co-incubated with liposomes shows that some specific peptide fragments of the oxidized SOD can interact with POPC liposomes. A comparison of the fractions detected in reverse-phase chromatography shows that specific SOD fragments are able to contribute to the reactivation of oxidized and fragmented SOD in the presence of POPC liposomes. The liposomes can recruit the potentially active fragment of SOD among the lethally damaged SOD fragments to elucidate the antioxidative function.     

Multiscale approach to explore the potential energy surface of water clusters (H2O)nn <or= 8

We propose a multiscale method to explore the energy landscape of water clusters. An asynchronous genetic algorithm is employed to explore the potential energy surface (PES) of OSS2 and TTM2.1-F models. Local minimum structures are collected on the fly, and the ultrafast shape recognition algorithm was used to remove duplicate structures. These structures are then refined at the B3LYP/6-31+G* level. The number of distinct local minima we found (21, 76, 369, 1443, and 3563 isomers for n = 4-8, respectively) reflects the complexity of the PES of water clusters.     

S100A9 in adult asthmatic patients: a biomarker for neutrophilic asthma

The biomarkers and therapeutic targets of neutrophilic asthma (NA) are poorly understood. Although S100 calcium-binding protein A9 (S100A9) has been shown to correlate with neutrophil activation, its role in asthma pathogenesis has not been clarified. This study investigated the mechanism by which S100A9 is involved in neutrophil activation, neutrophil extracellular trap (NET)-induced airway inflammation, and macrophage polarization in NA. The S100A9 levels (by ELISA) in sera/culture supernatant of peripheral blood neutrophils (PBNs) and M0 macrophages from asthmatic patients were measured and compared to those of healthy controls (HCs). The function of S100A9 was evaluated using airway epithelial cells (AECs) and PBNs/M0 macrophages from asthmatic patients, as well as a mouse asthma model. The serum levels of S100A9 were higher in NA patients than in non-NA patients, and there was a positive correlation between serum S100A9 levels and sputum neutrophil counts (r = 0.340, P = 0.005). Asthmatic patients with higher S100A9 levels had lower PC₂₀ methacholine values and a higher prevalence of severe asthma (SA) (P < .050). PBNs/M0 macrophages from SA released more S100A9 than those from non-SA patients. PBNs from asthmatic patients induced S100A9 production by AECs, which further activated AECs via the extracellular signal-regulated kinase (ERK) pathway, stimulated NET formation, and induced M1 macrophage polarization. Higher S100A9 levels in sera, bronchoalveolar lavage fluid, and lung tissues were observed in the mouse model of NA but not in the other mouse models. These results suggest that S100A9 is a potential serum biomarker and therapeutic target for NA.Subject terms: Prognostic markers, Adaptive immunity, Immunological disorders, Diagnostic markers     

Studies on thermal degradation of 1-4 and 1-2 polybutadienes in inert atmosphere

The degradation of 1,2 and 1,4 polybutadienes by heating in inert atmosphere was characterized by FTIR, NMR and TGA/TCT/GC/MS for the volatile organic compounds. Two distinct mass change stages in the thermogravimetric analysis indicated different temperature ranges of degradation. Below 300 °C, the predominant reactions depend on the chemical structure of PBs. Thus, M1 and M2 formation by heating 1,4-PB at 260 °C allows us to prove crosslinking reaction. On the other hand, heating 1,2-PB at 260 °C leads to decahydronaphthalene and methyl formation by cycloaddition and rearrangement. At about 300 °C, only radical scission occurs for 1,2-PB whereas Diels Alder and proton transfer mechanisms are described for 1,4-PB. The products of reaction are respectively conjugated diene, cyclic and linear unsaturated compounds sometimes with methyl groups. Above 400 °C, the main process is aromatisation for both PBs.     

Gain equalization of EDFA using a loop filter with a single polarization controller

A Sagnac loop filter with two pieces of high birefringence fiber having equal lengths,and spliced together at a fixed angle of 30°displacement between the two principle axes,is proposed in this letter.Gain equalization of erbium-doped fiber amplifiers(EDFAs) is implemented by tuning only the polarization controller in the loop filter.Experimental result shows that there remains a deviation of±1 dB in the region of the flattened profile with the useful bandwidth of about 23 nm,thereby demonstrating the effectiveness of the method.An effective mathematical model and mechanism is also given for further explanation.     

High-efficiency single and tandem fullerene solar cells with asymmetric monofluorinated diketopyrrolopyrrole-based polymer

Design and synthesis of low bandgap(LBG) polymer donors is inevitably challenging and their processability from a non-halogenated solvent system remains a hurdle to overcome in the area of highperformance polymer solar cells(PSCs).Due to a high aggregation tendency of LBG polymers,especially diketopyrrolopyrrole(DPP)-based polymers coupled with bithiophenes in the polymer backbones,their widespread adoption in non-ha logena ted solvent-processed PSCs has been limited.Herein,a novel LBG DPP-based...     

ChemInform Abstract: Theoretical Study of the Structural and Electronic Properties of SimGen and SimGen‐ (s = m + n ≤ 7) Clusters.

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