214 research outputs found
Radiation by cavity-backed antennas on a circular cylinder
Conformal antenna arrays are popular antennas for aircraft, spacecraft and land vehicle platforms due to their inherent low weight, cost and drag properties. However, to date there has been a dearth of rigorous analytical or numerical solutions to aid the designer. In fact, it has been common practice to use limited measurements and planar approximations in designing such non-planar antennas. The finite element-boundary integral method is extended to radiation by cavity-backed structures in an infinite, metallic cylinder. The formulation is used to investigate the effect of cavity size on the radiation pattern for typical circumferentially and axially polarized patch antennas. Curvature effect on the gain, pattern shape, and input impedance is also studied. Finally, the accuracy of the FE-BI approach for a microstrip patch array is demonstrated
Analysis of cylindrical wrap-around and doubly conformal patch antennas by way of the finite element-artificial absorber method
The goal of this project was to develop analysis codes for computing the scattering and radiation of antennas on cylindrically and doubly conformal platforms. The finite element-boundary integral (FE-BI) method has been shown to accurately model the scattering and radiation of cavity-backed patch antennas. Unfortunately extension of this rigorous technique to coated or doubly curved platforms is cumbersome and inefficient. An alternative approximate approach is to employ an absorbing boundary condition (ABC) for terminating the finite element mesh thus avoiding use of a Green's function. A FE-ABC method is used to calculate the radar cross section (RCS) and radiation pattern of a cavity-backed patch antenna which is recessed within a metallic surface. It is shown that this approach is accurate for RCS and antenna pattern calculations with an ABC surface displaced as little as 0.3 lambda from the cavity aperture. These patch antennas may have a dielectric overlay which may also be modeled with this technique
Diaquabis[3-(hydroxyimino)butanoato]nickel(II)
In the neutral, mononuclear title complex, [Ni(C4H6NO3)2(H2O)2], the Ni atom lies on a crystallographic inversion centre within a distorted octahedral N2O4 environment. Two trans-disposed anions of 3-hydroxyiminobutanoic acid occupy four equatorial sites, coordinated by the deprotonated carboxylate and protonated oxime groups and forming six-membered chelate rings, while the two axial positions are occupied by the water O atoms. The O atom of the oxime group forms an intramolecular hydrogen bond with the coordinated carboxylate O atom. The complex molecules are linked into chains along b by hydrogen bonds between the water O atom and the carboxylate O of a neighbouring molecule. The chains are linked by further hydrogen bonds into a layer structure
Recommended from our members
Optical-based smart structures for tamper-indicating applications
This report is a compilation of several related projects performed from 1991 through 1996 concerning the design, construction, and application of optical-based smart structure to tamper-indicating and sensing secure containers. Due to several influences, the projects were carried through to varying degrees of completion. Cancellation of the overall project at the client level motivated the authors to gather all of the technology and ideas about smart structures developed during these several projects, whether completed or just conceptualized, into one document. Although each section individually discusses a specific project, the overall document is written chronologically with each successive section showing how increased smart structure complexity was integrated into the container
Diaquabis[3-(hydroxyimino)butanoato]nickel(II): a triclinic polymorph
The title centrosymmetric mononuclear complex, [Ni(C4H6NO3)2(H2O)2], is a polymorph of the previously reported complex [Dudarenko et al. (2010 ▶). Acta Cryst. E66, m277–m278]. The NiII atom, lying on an inversion center, is six-coordinated by two carboxylate O atoms and two oxime N atoms from two trans-disposed chelating 3-hydroxyiminobutanoate ligands and two axial water molecules in a distorted octahedral geometry. The hydroxy group forms an intramolecular hydrogen bond with the coordinated carboxylate O atom. The complex molecules are linked in stacks along [010] by a hydrogen bond between the water O atom and the carboxylate O atom of a neighboring molecule. The stacks are further linked by O—H⋯O hydrogen bonds into a layer parallel to (001)
Phellinus linteus suppresses growth, angiogenesis and invasive behaviour of breast cancer cells through the inhibition of AKT signalling
The antitumour activity of a medicinal mushroom Phellinus linteus (PL), through the stimulation of immune system or the induction of apoptosis, has been recently described. However, the molecular mechanisms responsible for the inhibition of invasive behaviour of cancer cells remain to be addressed. In the present study, we demonstrate that PL inhibits proliferation (anchorage-dependent growth) as well as colony formation (anchorage-independent growth) of highly invasive human breast cancer cells. The growth inhibition of MDA-MB-231 cells is mediated by the cell cycle arrest at S phase through the upregulation of p27Kip1 expression. Phellinus linteus also suppressed invasive behaviour of MDA-MB-231 cells by the inhibition of cell adhesion, cell migration and cell invasion through the suppression of secretion of urokinase-plasminogen activator from breast cancer cells. In addition, PL markedly inhibited the early event in angiogenesis, capillary morphogenesis of the human aortic endothelial cells, through the downregulation of secretion of vascular endothelial growth factor from MDA-MB-231 cells. These effects are mediated by the inhibition of serine-threonine kinase AKT signalling, because PL suppressed phosphorylation of AKT at Thr308 and Ser473 in breast cancer cells. Taken together, our study suggests potential therapeutic effect of PL against invasive breast cancer
Ginseng and Ganoderma lucidum Use after Breast Cancer Diagnosis and Quality of Life: A Report from the Shanghai Breast Cancer Survival Study
Objective: To evaluate associations between quality of life (QOL) and use of ginseng and Ganoderma lucidum (G. lucidum) among breast cancer survivors. Methods: Included in this study were 4,149 women with breast cancer who participated in the Shanghai Breast Cancer Survival Study. Ginseng use was assessed at 6-, 18-, and 36-month post-diagnosis surveys; G. lucidum use was assessed at the 6- and 36-month surveys. QOL was evaluated at the 6- and 36-month surveys. Multiple linear regression models were used to examine associations between ginseng and G.lucidum use and QOL assessed at the 36-month survey, with adjustment for potential confounders and baseline QOL. Results: At 6 months post-diagnosis, 14.2 % of participants reported regular use of ginseng and 58.8 % reported use of G. lucidum. We found no significant associations between ginseng use at 6, 18, and 36 months post-diagnosis and participants’ total QOL score or individual scores for psychological, physical, or social well-being. Post-diagnosis G. lucidum use was positively associated with social well-being (adjusted mean difference: 1.26; 95 % CI: 0.66, 1.86), but was inversely associated with physical well-being (adjusted mean difference: 21.16; 95 % CI: 21.86, 20.47) with a dose-response pattern observed for cumulative number of times of use (P for trend,0.001 for both). Conclusion: We found no evidence that post-diagnosis ginseng use improved the QOL of breast cancer survivors. Post
Anti-inflammatory activity of edible oyster mushroom is mediated through the inhibition of NF-κB and AP-1 signaling
<p>Abstract</p> <p>Background</p> <p>Mushrooms are well recognized for their culinary properties as well as for their potency to enhance immune response. In the present study, we evaluated anti-inflammatory properties of an edible oyster mushroom (<it>Pleurotus ostreatus</it>) <it>in vitro </it>and <it>in vivo</it>.</p> <p>Methods</p> <p>RAW264.7 murine macrophage cell line and murine splenocytes were incubated with the oyster mushroom concentrate (OMC, 0-100 μg/ml) in the absence or presence of lipopolysacharide (LPS) or concanavalin A (ConA), respectively. Cell proliferation was determined by MTT assay. Expression of cytokines and proteins was measured by ELISA assay and Western blot analysis, respectively. DNA-binding activity was assayed by the gel-shift analysis. Inflammation in mice was induced by intraperitoneal injection of LPS.</p> <p>Results</p> <p>OMC suppressed LPS-induced secretion of tumor necrosis factor-α (TNF-α, interleukin-6 (IL-6), and IL-12p40 from RAW264.7 macrophages. OMC inhibited LPS-induced production of prostaglandin E2 (PGE<sub>2</sub>) and nitric oxide (NO) through the down-regulation of expression of COX-2 and iNOS, respectively. OMC also inhibited LPS-dependent DNA-binding activity of AP-1 and NF-κB in RAW264.7 cells. Oral administration of OMC markedly suppressed secretion of TNF-α and IL-6 in mice challenged with LPS <it>in vivo</it>. Anti-inflammatory activity of OMC was confirmed by the inhibition of proliferation and secretion of interferon-γ (IFN-γ), IL-2, and IL-6 from concanavalin A (ConA)-stimulated mouse splenocytes.</p> <p>Conclusions</p> <p>Our study suggests that oyster mushroom possesses anti-inflammatory activities and could be considered a dietary agent against inflammation. The health benefits of the oyster mushroom warrant further clinical studies.</p
GPR50 Interacts with TIP60 to Modulate Glucocorticoid Receptor Signalling
GPR50 is an orphan G-protein coupled receptor most closely related to the melatonin receptors. The physiological function of GPR50 remains unclear, although our previous studies implicate the receptor in energy homeostasis. Here, we reveal a role for GPR50 as a signalling partner and modulator of the transcriptional co-activator TIP60. This interaction was identified in a yeast-two-hybrid screen, and confirmed by co-immunoprecipitation and co-localisation of TIP60 and GPR50 in HEK293 cells. Co-expression with TIP60 increased perinuclear localisation of full length GPR50, and resulted in nuclear translocation of the cytoplasmic tail of the receptor, suggesting a functional interaction of the two proteins. We further demonstrate that GPR50 can enhance TIP60-coactiavtion of glucocorticoid receptor (GR) signalling. In line with in vitro results, repression of pituitary Pomc expression, and induction of gluconeogenic genes in liver in response to the GR agonist, dexamethasone was attenuated in Gpr50−/− mice. These results identify a novel role for GPR50 in glucocorticoid receptor signalling through interaction with TIP60
- …