Paramagnetic behaviour of silver nanoparticles generated by decomposition of silver oxalate

Silver oxalate Ag2C2O4, was already proposed for soldering applications, due to the formation when it is decomposed by a heat treatment, of highly sinterable silver nanoparticles. When slowly decomposed at low temperature (125 °C), the oxalate leads however to silver nanoparticles isolated from each other. As soon as these nanoparticles are formed, the magnetic susceptibility at room temperature increases from -3.14 10-7 emu.Oe-1.g-1 (silver oxalate) up to -1.92 10-7 emu.Oe-1.g-1 (metallic silver). At the end of the oxalate decomposition, the conventional diamagnetic behaviour of bulk silver, is observed from room temperature to 80 K. A diamagnetic-paramagnetic transition is however revealed below 80 K leading at 2 K, to silver nanoparticles with a positive magnetic susceptibility. This original behaviour, compared to the one of bulk silver, can be ascribed to the nanometric size of the metallic particles

Functional variants regulating LGALS1 (Galectin 1) expression affect human susceptibility to influenza A(H7N9)

The fatality of avian influenza A(H7N9) infection in humans was over 30%. To identify human genetic susceptibility to A(H7N9) infection, we performed a genome-wide association study (GWAS) involving 102 A(H7N9) patients and 106 heavily-exposed healthy poultry workers, a sample size critically restricted by the small number of human A(H7N9) cases. To tackle the stringent significance cutoff of GWAS, we utilized an artificial imputation program SnipSnip to improve the association signals. In single-SNP analysis, one of the top SNPs was rs13057866 of LGALS1. The artificial imputation (AI) identified three non-genotyped causal variants, which can be represented by three anchor/partner SNP pairs rs13057866/rs9622682 (AI P = 1.81 × 10-7), rs4820294/rs2899292 (2.13 × 10-7) and rs62236673/rs2899292 (4.25 × 10-7) respectively. Haplotype analysis of rs4820294 and rs2899292 could simulate the signal of a causal variant. The rs4820294/rs2899292 haplotype GG, in association with protection from A(H7N9) infection (OR = 0.26, P = 5.92 × 10-7) correlated to significantly higher levels of LGALS1 mRNA (P = 0.050) and protein expression (P = 0.025) in lymphoblast cell lines. Additionally, rs4820294 was mapped as an eQTL in human primary monocytes and lung tissues. In conclusion, functional variants of LGALS1 causing the expression variations are contributable to the differential susceptibility to influenza A(H7N9).link_to_OA_fulltex

Molecular Characterization and Possible Immune Function of Two Members of Interleukin Family from Trachinotus ovatus

Interleukins (ILs) are a group of cytokines which play a core regulatory role in the immune system. In the present study, two members of the IL family, IL7 and IL8, were detected in Trachinotus ovatus. IL7 and IL8 cDNAs of T. ovatus consist of a 492 bp and 300 bp ORF (open reading frame) encoding a polypeptide of 163 and 99 amino acids, respectively. Multiple sequence alignment revealed that IL7 and IL8 contain characteristic arrangements of several conserved cysteine residues, which in T. ovatus are in positions 20, 57, 67, 105, 140, 152 and 35, 37, 61, 78, respectively. The phylogenetic tree showed that all ILs fell into four categories. Moreover, IL7 and IL8 mRNA of T. ovatus were constitutively expressed at different levels in all examined tissues, except muscle. Transcripts of IL7 were mainly expressed in liver, intestine, kidney, stomach, and fin, while transcripts of IL8 were highly detected in the eye, liver, kidney, and intestine of healthy fish. After Photobacterium damselae innoculation, mRNA levels of IL7 were higher than IL8 in the spleen and intestine, however, mRNA expression levels of IL7 were lower than IL8 in kidney 3 h post-injection. These results suggest that the two IL molecules play an important role in the inflammatory response of T. ovatus

Molecular Characterization of MyD88 in Pinctada fucata and its Response to Lipopolysaccharides and Polyinosinic-cytidylic Acid

Myeloid differentiation factor 88 (MyD88) is a key and essential adapter involved in the interleukin-1 receptor (IL-1R) and toll-like receptor (TLR)-mediated activation signaling pathway. To investigate molecular characterization of MyD88 and its gene expression profile in response to stimulation by lipopolysaccharide (LPS) and polyinosinic-cytidylic acid (poly (I: C)), we isolated the MyD88 cDNA sequence in Pinctada fucata and analyzed expression patterns using quantitative real-time PCR. Sequence analysis indicated that Pf-MyD88 cDNA is 1463bp in length and contains a1050bp open reading frame that encodes a 349 α peptide. Pf-MyD88 has the highest similarity with homologues of Crassostrea gigas and highly conserved death and toll/IL-1R domains. Furthermore, during LPS and poly (I:C)-stimulated experiments in the gill, peak expression levels of Pf-MyD88 were detected at 2h and 8h with a 1.58-fold and 3.58-fold increase, respectively. The results revealed the existence of a MyD88-dependent signaling pathway in P. fucata and contributed to understanding the potential role of Pf-MyD88 in the TLR/IL-1R-mediated signaling pathway

Stable periodic oscillations in a two-stage cancer model of tumor and immune system interactions

This paper presents qualitative and bifurcation analysis near the degenerate equilibrium in a two-stage cancer model of interactions between lymphocyte cells and solid tumor and contributes to a better understanding of the dynamics of tumor and immune system interactions. We first establish the existence of Hopf bifurcation in the 3-dimensional cancer model and rule out the occurrence of the degenerate Hopf bifurcation. Then a general Hopf bifurcation formula is applied to determine the stability of the limit cycle bifurcated from the interior equilibrium. Sufficient conditions on the existence of stable periodic oscillations of tumor levels are obtained for the two-stage cancer model. Numerical simulations are presented to illustrate the existence of stable periodic oscillations with reasonable parameters and demonstrate the phenomenon of long-term tumor relapse in the model