1,134 research outputs found
Understanding Moral Psychology and Moral Education through the Lens of the Philosophy of Science
2009This article focuses on discussion concerning moral psychology and
moral education from the philosophy of science standpoint. The
theoretical model of Lakatos' program in the field of the philosophy of
science is introduced and the structure of moral psychology and moral
education is analyzed and evaluated by using Lakatos' scientific
research program as a theoretical framework. The article begins with a
review of the theoretical background of the philosophy of science, then
continues by analyzing and evaluating the structure of moral
psychology by using a theoretical framework from the philosophy of
science, and then considers the case of moral education. The authors
conclude with a brief description of significant directions for the
introduction of the natural sciences, such as neuroscience and
sociobiology, into moral psychology and moral education
Improving Neural Radiance Field using Near-Surface Sampling with Point Cloud Generation
Neural radiance field (NeRF) is an emerging view synthesis method that
samples points in a three-dimensional (3D) space and estimates their existence
and color probabilities. The disadvantage of NeRF is that it requires a long
training time since it samples many 3D points. In addition, if one samples
points from occluded regions or in the space where an object is unlikely to
exist, the rendering quality of NeRF can be degraded. These issues can be
solved by estimating the geometry of 3D scene. This paper proposes a
near-surface sampling framework to improve the rendering quality of NeRF. To
this end, the proposed method estimates the surface of a 3D object using depth
images of the training set and sampling is performed around there only. To
obtain depth information on a novel view, the paper proposes a 3D point cloud
generation method and a simple refining method for projected depth from a point
cloud. Experimental results show that the proposed near-surface sampling NeRF
framework can significantly improve the rendering quality, compared to the
original NeRF and a state-of-the-art depth-based NeRF method. In addition, one
can significantly accelerate the training time of a NeRF model with the
proposed near-surface sampling framework.Comment: 13 figures, 2 table
Homeobox gene Dlx-2 is implicated in metabolic stress-induced necrosis
<p>Abstract</p> <p>Background</p> <p>In contrast to tumor-suppressive apoptosis and autophagic cell death, necrosis promotes tumor progression by releasing the pro-inflammatory and tumor-promoting cytokine high mobility group box 1 (HMGB1), and its presence in tumor patients is associated with poor prognosis. Thus, necrosis has important clinical implications in tumor development; however, its molecular mechanism remains poorly understood.</p> <p>Results</p> <p>In the present study, we show that Distal-less 2 (Dlx-2), a homeobox gene of the Dlx family that is involved in embryonic development, is induced in cancer cell lines dependently of reactive oxygen species (ROS) in response to glucose deprivation (GD), one of the metabolic stresses occurring in solid tumors. Increased Dlx-2 expression was also detected in the inner regions, which experience metabolic stress, of human tumors and of a multicellular tumor spheroid, an <it>in vitro </it>model of solid tumors. Dlx-2 short hairpin RNA (shRNA) inhibited metabolic stress-induced increase in propidium iodide-positive cell population and HMGB1 and lactate dehydrogenase (LDH) release, indicating the important role(s) of Dlx-2 in metabolic stress-induced necrosis. Dlx-2 shRNA appeared to exert its anti-necrotic effects by preventing metabolic stress-induced increases in mitochondrial ROS, which are responsible for triggering necrosis.</p> <p>Conclusions</p> <p>These results suggest that Dlx-2 may be involved in tumor progression via the regulation of metabolic stress-induced necrosis.</p
Blockade of Airway Inflammation by Kaempferol via Disturbing Tyk-STAT Signaling in Airway Epithelial Cells and in Asthmatic Mice
Asthma is characterized by bronchial inflammation causing increased airway hyperresponsiveness and eosinophilia. The interaction between airway epithelium and inflammatory mediators plays a key role in the asthmatic pathogenesis. The in vitro study elucidated inhibitory effects of kaempferol, a flavonoid found in apples and many berries, on inflammation in human airway epithelial BEAS-2B cells. Nontoxic kaempferol at ≤20 μM suppressed the LPS-induced IL-8 production through the TLR4 activation, inhibiting eotaxin-1 induction. The in vivo study explored the demoting effects of kaempferol on asthmatic inflammation in BALB/c mice sensitized with ovalbumin (OVA). Mouse macrophage inflammatory protein-2 production and CXCR2 expression were upregulated in OVA-challenged mice, which was attenuated by oral administration of ≥10 mg/kg kaempferol. Kaempferol allayed the airway tissue levels of eotaxin-1 and eotaxin receptor CCR3 enhanced by OVA challenge. This study further explored the blockade of Tyk-STAT signaling by kaempferol in both LPS-stimulated BEAS-2B cells and OVA-challenged mice. LPS activated Tyk2 responsible for eotaxin-1 induction, while kaempferol dose-dependently inhibited LPS- or IL-8-inflamed Tyk2 activation. Similar inhibition of Tyk2 activation by kaempferol was observed in OVA-induced mice. Additionally, LPS stimulated the activation of STAT1/3 signaling concomitant with downregulated expression of Tyk-inhibiting SOCS3. In contrast, kaempferol encumbered STAT1/3 signaling with restoration of SOCS3 expression. Consistently, oral administration of kaempferol blocked STAT3 transactivation elevated by OVA challenge. These results demonstrate that kaempferol alleviated airway inflammation through modulating Tyk2-STAT1/3 signaling responsive to IL-8 in endotoxin-exposed airway epithelium and in asthmatic mice. Therefore, kaempferol may be a therapeutic agent targeting asthmatic diseases
PPM1A Controls Diabetic Gene Programming through Directly Dephosphorylating PPAR?? at Ser273
Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a master regulator of adipose tissue biology. In obesity, phosphorylation of PPAR gamma at Ser273 (pSer273) by cyclin-dependent kinase 5 (CDK5)/extracellular signal-regulated kinase (ERK) orchestrates diabetic gene reprogramming via dysregulation of specific gene expression. Although many recent studies have focused on the development of non-classical agonist drugs that inhibit the phosphorylation of PPAR gamma at Ser273, the molecular mechanism of PPAR gamma dephosphorylation at Ser273 is not well characterized. Here, we report that protein phosphatase Mg2+/Mn2+-dependent 1A (PPM1A) is a novel PPAR gamma phosphatase that directly dephosphorylates Ser273 and restores diabetic gene expression which is dysregulated by pSer273. The expression of PPM1A significantly decreases in two models of insulin resistance: diet-induced obese (DIO) mice and db/db mice, in which it negatively correlates with pSer273. Transcriptomic analysis using microarray and genotype-tissue expression (GTEx) data in humans shows positive correlations between PPM1A and most of the genes that are dysregulated by pSer273. These findings suggest that PPM1A dephosphorylates PPAR gamma at Ser273 and represents a potential target for the treatment of obesity-linked metabolic disorders
A New Doherty Combiner with Wide Bandwidth for Magnitude and Phase Balance Compensation
This paper proposes a novel Doherty combiner that uses a series and parallel resonant circuit for wideband. Unlike conventional combiners, the aim of the proposed combiners is to extend bandwidth for not only the magnitude bandwidth, but also phase balance by employing series and parallel resonant circuits at the output impedance of the peaking amplifier. Considering the load impedance of the peaking amplifier, the Doherty combiners were analyzed in the theory of this study by deriving the series and parallel resonant circuit values. The output phase balances are determined for the targeted bandwidth to achieve uniform phase balance in the proposed combiner I using a series resonator. For better magnitude bandwidth, the slope of reflection coefficient (Γ) at port 3 in the combiner II using series resonator was derived using the derivative of Γ with respect to ω. Experimental results show that the proposed combiner I has 63.5% magnitude fractional bandwidth (FBW) and 118% FBW with the phase balance at ±2.5°. The proposed combiner II also has 85% magnitude FBW and 118% FBW with the phase balance at ±2.5°
UDP-Induced Phagocytosis and ATP-Stimulated Chemotactic Migration Are Impaired in STIM1
STIM1 is the only currently known intracellular calcium sensor that functions as the calcium influx regulator controlling immune cell activation. STIM1 function in immune cell calcium signalling has been studied extensively; however, its role in microglia, innate immune cells in brain, has not been fully understood. Here, we report that STIM1−/− murine microglia lost store-operated calcium influx and displayed aberrant immunological functions. Microglial functions regulated by chronic and global Ca2+i changes were reduced significantly, including cytokine releases and opsonin-dependent phagocytosis. More dramatically, cellular functions governed by Ca2+ regulation in local microdomains at the cell periphery, such as UDP-induced phagocytosis and ATP-stimulated chemotactic migration, were severely reduced in STIM1−/− microglia. Interestingly, UDP-induced Orai1 mobilization to the peripheral region was greatly attenuated in STIM1−/− microglia. Their chemotactic migration defect was reproduced in vivo in embryonic brain; the aggregated number of STIM1−/− microglia in LPS- (lipopolysaccharide-) injected lesions was much smaller than that in wild-type microglia. Furthermore, the neuron phagoptosis activities of activated microglia were significantly diminished in the STIM1−/− microglia. These in vitro and in vivo results suggest that STIM1-mediated store-operated calcium entry is important for the regulation of global Ca2+i changes which differentiates into active immune state of microglia, but it is more crucial for the regulation of local [Ca2+] microdomains which mediates the acute motility of murine microglia
JNK pathway is involved in the inhibition of inflammatory target gene expression and NF-kappaB activation by melittin
<p>Abstract</p> <p>Background</p> <p>Bee venom therapy has been used to treat inflammatory diseases including rheumatoid arthritis in humans and in experimental animals. We previously found that bee venom and melittin (a major component of bee venom) have anti-inflammatory effect by reacting with the sulfhydryl group of p50 of nuclear factor-kappa B (NF-κB) and IκB kinases (IKKs). Since mitogen activated protein (MAP) kinase family is implicated in the NF-κB activation and inflammatory reaction, we further investigated whether activation of MAP kinase may be also involved in the anti-inflammatory effect of melittin and bee venom.</p> <p>Methods</p> <p>The anti-inflammatory effects of melittin and bee venom were investigated in cultured Raw 264.7 cells, THP-1 human monocytic cells and Synoviocytes. The activation of NF-κB was investigated by electrophoretic mobility shift assay. Nitric oxide (NO) and prostaglandin E<sub>2 </sub>(PGE<sub>2</sub>) were determined either by Enzyme Linked Immuno Sorbent Assay or by biochemical assay. Expression of IκB, p50, p65, inducible nitric oxide synthetase (iNOS), cyclooxygenase-2 (COX-2) as well as phosphorylation of MAP kinase family was determined by Western blot.</p> <p>Results</p> <p>Melittin (0.5–5 μg/ml) and bee venom (5 and 10 μg/ml) inhibited lipopolysaccharide (LPS, 1 μg/ml) and sodium nitroprusside (SNP, 200 μM)-induced activation of c-Jun NH2-terminal kinase (JNK) in RAW 264.7 cells in a dose dependent manner. However, JNK inhibitor, anthra [1,9-cd]pyrazole-6 (2H)-one (SP600215, 10–50 μM) dose dependently suppressed the inhibitory effects of melittin and bee venom on NF-κB dependent luciferase and DNA binding activity via suppression of the inhibitory effect of melittin and bee venom on the LPS and SNP-induced translocation of p65 and p50 into nucleus as well as cytosolic release of IκB. Moreover, JNK inhibitor suppressed the inhibitory effects of melittin and bee venom on iNOS and COX-2 expression, and on NO and PGE<sub>2 </sub>generation.</p> <p>Conclusion</p> <p>These data show that melittin and bee venom prevent LPS and SNP-induced NO and PGE<sub>2 </sub>production via JNK pathway dependent inactivation of NF-κB, and suggest that inactivation of JNK pathways may also contribute to the anti-inflammatory and anti-arthritis effects of melittin and bee venom.</p
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