Melt Processable Novolac Cyanate Ester/Biphenyl Epoxy Copolymer Series with Ultrahigh Glass-Transition Temperature.

The rapid progress in silicon carbide (SiC)-based technology for high-power applications expects an increasing operation temperature (up to 250 °C) and awaits reliable packaging materials to unleash their full power. Epoxy-based encapsulant materials failed to provide satisfactory protection under such high temperatures due to the intrinsic weakness of epoxy resins, despite their unmatched good adhesion and processability. Herein, we report a series of copolymers made by melt blending novolac cyanate ester and tetramethylbiphenyl epoxy (NCE/EP) that have demonstrated much superior high-temperature stability over current epoxies. Benefited from the aromatic, rigid backbone and the highly functional nature of the monomers, the highest values achieved for the copolymers are as follows: glass-transition temperature (Tg) above 300 °C, decomposition onset above 400 °C, and char yield above 45% at 800 °C, which are among the highest of the known epoxy chemistry by far. Moreover, the high-temperature aging (250 °C) experiments showed much reduced mass loss of these copolymers compared to the traditional high-temperature epoxy and even the pure NCE in the long term by suppressing hydrolysis degradation mechanisms. The copolymer composition, i.e., NCE to EP ratio, has found to have profound impacts on the resin flowability, thermomechanical properties, moisture absorption, and dielectric properties, which are discussed in this paper with in-depth analysis on their structure-property relationships. The outstanding high-temperature stability, preferred and adjustable processability, and the dielectric properties of the reported NCE/EP copolymers will greatly stimulate further research to formulating robust epoxy molding compounds (EMCs) or underfill for packaging next-generation high-power electronics.

Pregnancy in postpartum estrus induces inflammatory milk production and catagen specific pup skin inflammation in interleukin-10 deficient mice.

BACKGROUND: The interleukin 10 deficient mice (IL-10(-/-)) showed high incidence of pup alopecia compared to other strains, and pup alopecia was caused by skin inflammation and was recoverable. Pup alopecia of B6.IL-10(-/-) might be related with maternal factor and interleukin-10 deficient phenotype. OBJECTIVE: The objectives of this study were elucidating of maternal factors for inflammatory milk production and characterization of pup alopecia in IL-10(-/-) mice. METHODS: Incidences of pup alopecia were analyzed with 13 breeding cases. Comparison between control and alopecia pups and its dams, were conducted with histological examination (H&E, TUNEL assay, immunohistochemistry for F4/80, iNOS, CD206, Gr-1, CD4, CD8, CD11c and CD326), fostering test, forced weaning test, qPCR for tyrosine hydroxylase, flow cytometry, IL-10 inhibition test, BMDM stimulation test and LC/MS analysis. RESULTS: Presence of pregnancy in postpartum estrus showed significant correlation with inflammatory milk production and mammary gland involution in B6.IL-10(-/-) mice. There were no different mass in inflammatory milk, but different ionization intensity was detected. Inflammatory milk directly induced hepatocyte steatosis, catagen stage specific hair breaking and alopeicia in pups. Histologically, hypertropy of outer root sheath and macrophage/neutrophil infiltration were typical. CONCLUSION: B6.IL-10(-/-) dam with stress such as PPE could produce untimely mammary gland involution and inflammatory milk production. Interleukin 10 is important for maternal stress regulation and protecting inflammatory milk production, also influence severity of pup skin inflammation and alopecia. Remarkably, inflammatory milk induced hepatocyte steatosis, and it could indicate there is abnormal lipid metabolism. This was first report for catagen specific alopecia in mouse.

Action of lipopolysaccharide on interstitial cells of cajal from mouse small intestine.

BACKGROUND AND PURPOSE: Lipopolysaccharide (LPS) induces intestinal dysmotility by alteration of smooth muscle and enteric neuronal activities. However, there is no report on the modulatory effects of LPS on the interstitial cells of Cajal (ICCs). We investigated the effect of LPS and its signal transduction in ICCs. METHODS: We performed whole-cell patch clamp and RT-PCR in cultured ICCs from mouse small intestine. RESULTS: LPS suppressed the generation of pacemaker currents of ICCs. The mRNA transcripts for Toll-like receptor 4 (TLR4) were expressed in ICCs. However, the inhibitory action of LPS on pacemaker currents from TLR4(+/+) mice was not present in TLR4(-/-) mice. The inhibitory effects of LPS on ICCs were blocked by glibenclamide (an inhibitor of ATP-sensitive K(+) channels), NS-398 (a COX-2 inhibitor), AH6808 [a prostaglandin E(2) (PGE(2))-EP(2) receptor antagonist], ODQ (an inhibitor of guanylate cyclase) and L-NAME [an inhibitor of nitric oxide synthase (NOS)]. Furthermore, genistein and herbimycin A (tyrosine kinase inhibitors) blocked the LPS-induced inhibitory action on pacemaker activity in ICCs. CONCLUSIONS: LPS can activate ICCs to release NO and PGE(2) through TLR4 activation. The released NO and PGE(2) inhibit pacemaker currents by activating ATP-sensitive K(+) channels. The LPS actions are mediated by tyrosine kinase signaling pathways.

Suppression of inflammation response by a novel A3 adenosine receptor agonist thio-Cl-IB-MECA through inhibition of Akt and NF-κB signaling.

Adenosine, a purine nucleoside, is released from metabolically active cells into extracellular space and plays an important role in various pathophysiological processes. Adenosine regulates many biological responses including inflammation by the interaction with their receptors such as A1, A(2A), A(2B), and A3. Especially, A3 adenosine receptor (A3AR) is considered to be expressed in macrophage cells. To the end, A3AR agonists have been reported to have an anti-inflammatory activity. In our continuous efforts to develop new anti-inflammatory agents, we found a novel adenosine analog, 2-chloro-N6-(3-iodobenzyl)-4'-thioadenosine-5'-N-methyluronamide (thio-Cl-IB-MECA), was a potent human A3AR agonist. The study was designed to investigate whether thio-Cl-IB-MECA has an anti-inflammatory potential in mouse macrophage RAW 264.7 cells and mouse sepsis model in vivo. Thio-Cl-IB-MECA exhibited an effective anti-inflammatory activity. The expression of pro-inflammatory biomarkers including inducible nitric oxide synthase (iNOS), interleukin-1ß (IL-1ß), and tumor necrosis factor (TNF-α) was suppressed by the treatment of thio-Cl-IB-MECA in the protein and mRNA levels in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells. Further examination revealed that thio-Cl-IB-MECA inhibited LPS-induced phosphatidylinositol 3-kinase (PI3 kinase)/Akt activation, NF-kB binding activity, and ß-catenin expression. In addition, in in vivo LPS-induced mouse endotoxemia model, thio-Cl-IB-MECA exerted the increase of survival rate compared to vehicle-treated mouse. The analysis of the protein levels of iNOS, IL-1ß, and TNF-α was also suppressed by the compound-treated groups in lung tissues. These results suggest that thio-Cl-IB-MECA might have an anti-inflammatory activity through the inhibition of pro-inflammatory cytokine expression by modulating PI3K/Akt and NF-κB signaling pathways.

Modulation of acute and chronic inflammatory processes by a traditional medicine preparation GCSB-5 both in vitro and in vivo animal models.

AIM OF THIS STUDY: GCSB-5 is a traditional medicine preparation composed with six oriental herbs which have been widely used for the inflammatory diseases in Asia. In the present study, we have demonstrated the anti-inflammatory effects of GCSB-5 in vivo and in vitro along with its underlying mechanism of action. METHODS: The acute and chronic inflammation models in animals were applied to investigate the anti-inflammatory effects of GCSB-5. To further investigate the mechanism of the anti-inflammatory activity, lipopolysaccharide (LPS)-induced murine macrophage RAW264.7 cells were also employed. RESULTS: In in vivo animal model, oral administration of GCSB-5 significantly inhibited TPA- and carrageenan-induced acute edema and adjuvant-induced arthritis. The vascular permeability, leukocyte migration, and granuloma formation were also inhibited by GCSB-5. In accordance, GCSB-5 suppressed the LPS-induced nitric oxide (NO) production by the downregulation of mRNA and protein expressions of inducible nitric oxide synthase (iNOS). GCSB-5 also suppressed the expressions of cyclooxygenase-2 (COX-2) and inflammatory cytokines such as interleukin-1beta and interferon-beta. The activation of NF-kappaB by LPS was also alleviated by GCSB-5, which correlated with its inhibitory effect on IkB degradation. The signaling pathway with the activation of Akt was also attenuated by the treatment by GCSB-5. CONCLUSIONS: Taken together, our results demonstrate that GCSB-5 reduces the development of acute and chronic inflammation and its anti-inflammatory property might in part be a function of the inhibition of iNOS and COX-2 expression via down-regulation of the Akt signal pathway and inhibition of NF-kappaB activation. These findings suggest that GCSB-5 might be an applicable therapeutic traditional medicine in the regulation of the inflammatory response.