57 research outputs found
High Quality Factor Silicon Cantilever Driven by PZT Actuator for Resonant Based Mass Detection
A high quality factor (Q-factor) piezoelectric lead zirconat titanate (PZT)
actuated single crystal silicon cantilever was proposed in this paper for
resonant based ultra-sensitive mass detection. Energy dissipation from
intrinsic mechanical loss of the PZT film was successfully compressed by
separating the PZT actuator from resonant structure. Excellent Q-factor, which
is several times larger than conventional PZT cantilever, was achieved under
both atmospheric pressure and reduced pressures. For a 30 micrometer-wide 100
micrometer-long cantilever, Q-factor was measured as high as 1113 and 7279
under the pressure of 101.2 KPa and 35 Pa, respectively. Moreover, it was found
that high-mode vibration can be realized by the cantilever for the pursuit of
great Q-factor, while support loss became significant because of the increased
vibration amplitude at the actuation point. An optimized structure using
node-point actuation was suggested then to suppress corresponding energy
dissipation.Comment: Submitted on behalf of EDA Publishing Association
(http://irevues.inist.fr/handle/2042/16838
Interaction between lung cancer cells and astrocytes via specific inflammatory cytokines in the microenvironment of brain metastasis
The incidence of brain metastasis is increasing, however, little is known about molecular mechanism responsible for lung cancer-derived brain metastasis and their development in the brain. In the present study, brain pathology was examined in an experimental model system of brain metastasis as well as in human brain with lung cancer metastasis. In an experimental model, after 3–6 weeks of intracardiac inoculation of human lung cancer-derived (HARA-B) cells in nude mice, wide range of brain metastases were observed. The brain sections showed significant increase in glial fibrillary acidic protein (GFAP)-positive astrocytes around metastatic lesions. To elucidate the role of astrocytes in lung cancer proliferation, the interaction between primary cultured mouse astrocytes and HARA-B cells was analyzed in vitro. Co-cultures and insert-cultures demonstrated that astrocytes were activated by tumor cell-oriented factors; macrophage migration inhibitory factor (MIF), interleukin-8 (IL-8) and plasminogen activator inhibitor-1 (PAI-1). Activated astrocytes produced interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β), which in turn promoted tumor cell proliferation. Semi-quantitative immunocytochemistry showed that increased expression of receptors for IL-6 and its subunits gp130 on HARA-B cells. Receptors for TNF-α and IL-1β were also detected on HARA-B cells but down-regulated after co-culture with astrocytes. Insert-culture with astrocytes also stimulated the proliferation of other lung cancer-derived cell lines (PC-9, QG56, and EBC-1). These results suggest that tumor cells and astrocytes stimulate each other and these mutual relationships may be important to understand how lung cancer cells metastasize and develop in the brain
Iridoids and Anthraquinones from the Malaysian Medicinal Plant, Saprosma scortechinii (Rubiaceae)
A further investigation of the leaves and stems of Saprosma scortechinii afforded 13 compounds, of which 10 are new compounds. These were elucidated as the bis-iridoid glucosides, saprosmosides G (1) and H (2), the iridoid glucoside, 6-O-epi-acetylscandoside (3), and the anthraquinones, 1-methoxy-3-hydroxy-2-carbomethoxy-9,10-anthraquinone (4), 1-methoxy-3-hydroxy-2-carbomethoxy-9,10-anthraquinone 3-O-β-primeveroside (5), 1,3-dihydroxy-2-carbomethoxy-9,10-anthraquinone 3-O-β-primeveroside (6), 1,3,6-trihydroxy-2-methoxymethyl-9,10-anthraquinone (7), 1-methoxy-3,6-dihydroxy-2-hydroxymethyl-9,10-anthraquinone (8), 1,3,6-trihydroxy-2-hydroxymethyl-9,10-anthraquinone 3-O-β-primeveroside (9), and 3,6-dihydroxy-2-hydroxymethyl-9,10-anthraquinone (10). Structure assignments for all compounds were established by means of mass and NMR spectroscopies, chemical methods, and comparison with published data. The new anthraquinones were derivatives of munjistin and lucidin
Head-to-head comparison of the safety of tocilizumab and tumor necrosis factor inhibitors in rheumatoid arthritis patients (RA) in clinical practice: results from the registry of Japanese RA patients on biologics for long-term safety (REAL) registry
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