36,705 research outputs found
Journey of water in pine cones
Pine cones fold their scales when it rains to prevent seeds from short-distance dispersal. Given that the scales of pine cones consist of nothing but dead cells, this folding motion is evidently related to structural changes. In this study, the structural characteristics of pine cones are studied on micro-/macro-scale using various imaging instruments. Raindrops fall along the outer scales to the three layers (bract scales, fibers and innermost lignified structure) of inner pine cones. However, not all the layers but only the bract scales get wet and then, most raindrops move to the inner scales. These systems reduce the amount of water used and minimize the time spent on structural changes. The result shows that the pine cones have structural advantages that could influence the efficient motion of pine cones. This study provides new insights to understand the motion of pine cones and would be used to design a novel water transport system.119Ysciescopu
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KWM: Knowledge-based Workflow Model for agile organization
The workflow management system (WFMS) in an agile organization should be highly adaptable to the frequent organizational changes. To increase the adaptability of contemporary WFMSs, a mechanism for managing changes within the organizational structure and changes in business rules needs to be reinforced. In this paper, a knowledge-based approach for workflow modeling is proposed, in which a workflow is defined as a set of business rules. Knowledge on the organizational structure and special workflow, such as role/actor mappings and complex routing rules, can be explicitly modeled in KWM (Knowledge-based Workflow Model).
Using knowledge representation scheme and dependency management facility, a change propagation mechanism is provided to adapt to the frequent changes in the organizational structure, business rules, and procedures
Twisted atrioventricular connections in double inlet right ventricle: evaluation by magnetic resonance imaging
Twisted atrioventricular connections occur almost exclusively in the hearts with biventricular atrioventricular connections. Only one example of double inlet left ventricle has been illustrated in which the axes of the two atrioventricular valves crossed each other. We describe herein three patients, and one autopsied specimen, with double inlet right ventricle in which magnetic resonance imaging clearly demonstrated twisted atrioventricular connections
Strengthening of RC slabs with large penetrations using anchored FRP composites
Large penetrations are routinely made in existing reinforced concrete (RC) slabs due to structural and/or functional changes. Externally bonded fibre-reinforced polymer (FRP) composites can in turn be bonded to the tension face of the slab in the immediate vicinity of the penetration in order to restore the strength of the slab due to the lost internal steel reinforcement. In order to prevent premature debonding failure of the FRP strengthening, anchors can be applied. The results of tests on the strength and behaviour of one-way spanning RC slabs with large central penetrations which have been strengthened with unanchored and anchored FRP composites are presented in this paper. The FRP strengthening was found to be effective in strengthening penetrated slabs and the anchors were found to be effective in controlling the propagation of debonding cracks.published_or_final_versionThe 2nd Official International Conference of International Institute for FRP in Construction for Asia-Pacific Region (APFIS 2009), Seoul, Korea, 9-11 December 2009. In Proceedings of the 2nd APFIS, 2009, p. 111-11
Electrical property improvements of high-k gate oxide by in situ nitrogen incorporation during atomic layer deposition
Atomic layer deposition (ALD) process for oxynitrides of high-k gate dielectrics employing NH4OH as a single source for reactants, water and NH3, was studied. By this method, nitrogen was incorporated up to 1-3 at. % for ALD Al2O3 and Ta2O5 films from metal organic precursors. A comparative study with water based ALD showed that the electrical properties were improved. The leakage current of oxide films from NH4OH based ALD had been reduced and, more importantly, the dielectric strength was found to be enhanced by more than two orders of magnitude from a time dependent dielectric breakdown measurement. (c) 2007 American Institute of Physics.X119sciescopu
High performance thin film transistor with low temperature atomic layer deposition nitrogen-doped ZnO
High performance thin film transistor (TFT) with atomic layer deposition (ALD) nitrogen doped ZnO (ZnO:N) as an active layer is demonstrated. The electrical properties of ZnO thin films were effectively controlled by in situ nitrogen doping using NH4OH as a source for reactants. Especially, the electron concentration in ZnO was lowered to below 10(15) cm(-3). Good device characteristics were obtained from the inverted staggered type TFTs with ZnO:N channel and ALD Al2O3 gate insulator; mu(sat)=6.7 cm(2)/V s, I-off=2.03x10(-12) A, I-on/off=9.46x10(7), and subthreshold swing=0.67 V/decade. The entire TFT fabrication processes were carried out at below 150 degrees C, which is a favorable process for plastic based flexible display. (C) 2007 American Institute of Physics.X11126sciescopu
Inhibitory Effect of the root of Polygala tenuifolia on Bradykinin and COX 2-Mediated Pain and Inflammatory Activity
Purpose: To gain insight into the mechanisms of analgesic and anti-inflammatory activities of the root extract of Polygala tenuifolia.Methods: Polygala tenuifolia was extracted with 70 % methanol and tested for analgesic and antiinflammatory activities (0.1, 1, 10 and 100 mg/kg) using the following models: acetic acid-induced writhing, rat paw edema, bradykinin inhibtion with rat ileum, and prostaglandin assay.Results: Administration of the Polygala tenuifolia extract at 100 mg/kg dose produced significant analgesic effect on acetic acid-induced writhing (97 % inhibition) but its effect in the tail-flick test was not significant (p < 0.05). In addition, the extract exerted significant anti-inflammatory effect in the rat paw edema model (8 to 33 % inhibition) at doses ranging from 0.1 - 100.0 mg/kg). A significant inhibitory action (53%) on the bradykinin-mediated contractions of rat ileum was also observed. Furthermore, the extract significantly (p < 0.05) inhibited the production of lipopolysaccharides-induced 6-keto-PGF1α by 28% in macrophage cultures.Conclusion: These results provide evidence that the Polygala tenuifolia root extract exerts analgesic and anti-inflammatory effects via its significant inhibitory effect on acetic acid writhing test, bradykinin-mediated actions as well as on 6-keto-PGF1α induction.Keywords: Polygalae radix, Bradylinin, Prostaglandin, COX-2, Inflammation, Analgesi
Inhibition of iNOS and DNA Oxidation by Methanol Extract of Schizonepeta tenuifolia
Purpose: To investigate the antioxidant properties of the methanol extract of S. tenuifolia as well as its effect on inducible nitric oxide synthase (iNOS) and cycleooxygenase-2 (COX-2) expression in lipopolysaccharides (LPS)-induced cell damage in macrophage cells.Methods: The antioxidant activities of the plant extract were explored by measuring free radical scavenging activity, viz, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO), and deoxyribose oxidation levels. The mechanism of antioxidant action of the extract was determined by Western blot analysis for iNOS and COX-2 expression in LPS-stimulated RAW 264.7 cells.Results: The extract contained antioxidant components, including phenolics, flavonoids and anthocyanin and exerted significant radical scavenging activity in a dose-dependent manner. It also produced deoxyribose oxidation and dramatic reducing power. Production of iNOS induced by LPS was significantly inhibited by the extract, suggesting that the extract inhibits nitric oxide (NO) production by suppressing iNOS expression. However, COX-2 induced by LPS was not significantly affected by the extract.Conclusion: These results suggest that the methanol extract of S. tenuifolia exerts significant antioxidant activity via inhibition of free radicals, iNOS and DNA oxidation
Weakening of the stratospheric polar vortex by Arctic sea-ice loss
Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea-ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea-ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhances the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January-February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.open11167174Ysciescopu
Cisplatin induces tolerogenic dendritic cells in response to TLR agonists via the abundant production of IL-10, thereby promoting Th2-and Tr1-biased T-cell immunity
Although many advantageous roles of cisplatin (cis-diamminedichloroplatinum (II), CDDP) have been reported in cancer therapy, the immunomodulatory roles of cisplatin in the phenotypic and functional alterations of dendritic cells (DCs) are poorly understood. Here, we investigated the effect of cisplatin on the functionality of DCs and the changes in signaling pathways activated upon toll-like receptor (TLR) stimulation. Cisplatin-treated DCs down-regulated the expression of cell surface molecules (CD80, CD86, MHC class I and II) and up-regulated endocytic capacity in a dose-dependent manner. Upon stimulation with various TLR agonists, cisplatin-treated DCs showed markedly increased IL-10 production through activation of the p38 MAPK and NF-kappa B signaling pathways without altering the levels of TNF-alpha and IL-12p70, indicating the cisplatin-mediated induction of tolerogenic DCs. This effect was dependent on the production of IL-10 from DCs, as neither DCs isolated from IL-10(-/-) mice nor IL-10-neutralized DCs generated tolerogenic DCs. Interestingly, DCs that were co-treated with cisplatin and lipopolysaccharide (LPS) exhibited a decreased immunostimulatory capacity for inducing the proliferation of Th1- and Th17-type T cells; instead, these DCs contributed to Th2-type T cell immunity. Furthermore, in vitro and in vivo investigations revealed a unique T cell population, IL-10-producing CD3(+)CD4(+)LAG-3(+)CD49b(+)CD25(-)Foxp3(-) Tr1 cells, that was significantly increased without altering the Foxp3(+) regulatory T cell population. Taken together, our results suggest that cisplatin induces immune-suppressive tolerogenic DCs in TLR agonist-induced inflammatory conditions via abundant IL-10 production, thereby skewing Th cell differentiation towards Th2 and Tr1 cells. This relationship may provide cancer cells with an opportunity to evade the immune system.1123Ysciescopu
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