273 research outputs found

    Does Rational Bubbles Exist in the Taiwan Stock Market? Evidence from a Nonparametric Cointegration Test

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    In this study, we revisit the issue as to the presence of rational bubbles in the Taiwan stock market during the June 1991 to February 2005 period using the Bierens (1997) nonparametric cointegration tests. The results from the Bierens nonparametric cointegration test attest to the absence of rational bubbles in the Taiwan stock market.Rational Bubbles Taiwan Stock Market Nonparametric Cointegration Test

    Investigating Thermal Comfort and User Behaviors in Outdoor Spaces: A Seasonal and Spatial Perspective

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    Numerous studies have examined the correlation between the number of attendants in a given outdoor environment and thermal indices to understand how the environmental planning has an impact on the users. However, extensive observations should be conducted to examine the detailed static and dynamic behavior patterns of users. We conducted dynamic observations at a stepped plaza to perform on-site measurements of the physical environment and observations of users behaviors, including their resting positions, movements, and stay durations. The results indicated that more people rested on the steps during the cool season than hot season. Compared to neutral temperatures, people demonstrated higher heat tolerance to the hot season. The results indicated that more than 75% of users preferred to remain in shaded areas and stayed longer than in the sunlight. The people tended to engage in static activities in environments that exhibit sufficient shading. The shaded areas were conducive to static activities as the summer grew hotter. The results verified that the people of Taiwan would avoid sunlight and desire shaded spaces based on their previous climate experiences and expectations, which can serve as a reference for outdoor space design to improve the usability and quality of open urban spaces

    Explore the Functional Connectivity between Brain Regions during a Chemistry Working Memory Task.

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    Previous studies have rarely examined how temporal dynamic patterns, event-related coherence, and phase-locking are related to each other. This study assessed reaction-time-sorted spectral perturbation and event-related spectral perturbation in order to examine the temporal dynamic patterns in the frontal midline (F), central parietal (CP), and occipital (O) regions during a chemistry working memory task at theta, alpha, and beta frequencies. Furthermore, the functional connectivity between F-CP, CP-O, and F-O were assessed by component event-related coherence (ERCoh) and component phase-locking (PL) at different frequency bands. In addition, this study examined whether the temporal dynamic patterns are consistent with the functional connectivity patterns across different frequencies and time courses. Component ERCoh/PL measured the interactions between different independent components decomposed from the scalp EEG, mixtures of time courses of activities arising from different brain, and artifactual sources. The results indicate that the O and CP regions' temporal dynamic patterns are similar to each other. Furthermore, pronounced component ERCoh/PL patterns were found to exist between the O and CP regions across each stimulus and probe presentation, in both theta and alpha frequencies. The consistent theta component ERCoh/PL between the F and O regions was found at the first stimulus and after probe presentation. These findings demonstrate that temporal dynamic patterns at different regions are in accordance with the functional connectivity patterns. Such coordinated and robust EEG temporal dynamics and component ERCoh/PL patterns suggest that these brain regions' neurons work together both to induce similar event-related spectral perturbation and to synchronize or desynchronize simultaneously in order to swiftly accomplish a particular goal. The possible mechanisms for such distinct component phase-locking and coherence patterns were also further discussed

    AMP-Activated Protein Kinase Activation during Cardioplegia-Induced Hypoxia/Reoxygenation Injury Attenuates Cardiomyocytic Apoptosis via Reduction of Endoplasmic Reticulum Stress

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    Cardioplegic-induced H/R injury results in cardiomyocytic apoptosis. AMPK has been shown to reduce ER stress and the unfolded protein response (UPR). Whether AMPK activation can attenuate cardiomyocytic apoptosis after cardioplegia-induced H/R injury is unknown. Cardiomyocytes were exposed to simulated ischemia by incubation in a hypoxic chamber with intermittent cold cardioplegia solution infusion at 20-minute intervals and subsequently reoxygenated in a normoxic environment. Various doses of AMPK activators (AICAR or metformin) were given 2 days before H/R injury. The cardiomyocytes were harvested after reoxygenation for subsequent examination. With both AMPK activators, the antiapoptotic genes of ER stress and UPR, the subsequent production of proapoptotic proteins was attenuated, and the antiapoptotic proteins were elevated. The activity of the apoptotic effectors of ER stress was also reduced with AMPK activation. Moreover, TUNEL staining showed that AMPK activation significantly reduced the percentage of apoptotic cardiomyocytes after cardioplegia-induced H/R injury. Our results revealed that AMPK activation during cardioplegia-induced H/R injury attenuates cardiomyocytic apoptosis, via enhancement of antiapoptotic and reduction of proapoptotic responses, resulting from lessening ER stress and the UPR. AMPK activation may serve as a future pharmacological target to reduce H/R injury in the clinical setting

    The nucleolar protein NIFK promotes cancer progression via CK1α/β-catenin in metastasis and Ki-67-dependent cell proliferation.

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    Nucleolar protein interacting with the FHA domain of pKi-67 (NIFK) is a Ki-67-interacting protein. However, its precise function in cancer remains largely uninvestigated. Here we show the clinical significance and metastatic mechanism of NIFK in lung cancer. NIFK expression is clinically associated with poor prognosis and metastasis. Furthermore, NIFK enhances Ki-67-dependent proliferation, and promotes migration, invasion in vitro and metastasis in vivo via downregulation of casein kinase 1α (CK1α), a suppressor of pro-metastatic TCF4/β-catenin signaling. Inversely, CK1α is upregulated upon NIFK knockdown. The silencing of CK1α expression in NIFK-silenced cells restores TCF4/β-catenin transcriptional activity, cell migration, and metastasis. Furthermore, RUNX1 is identified as a transcription factor of CSNK1A1 (CK1α) that is negatively regulated by NIFK. Our results demonstrate the prognostic value of NIFK, and suggest that NIFK is required for lung cancer progression via the RUNX1-dependent CK1α repression, which activates TCF4/β-catenin signaling in metastasis and the Ki-67-dependent regulation in cell proliferation

    Intensity modulated radiotherapy for elderly bladder cancer patients

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    <p>Abstract</p> <p>Background</p> <p>To review our experience and evaluate treatment planning using intensity-modulated radiotherapy (IMRT) and helical tomotherapy (HT) for the treatment of elderly patients with bladder cancer.</p> <p>Methods</p> <p>From November 2006 through November 2009, we enrolled 19 elderly patients with histologically confirmed bladder cancer, 9 in the IMRT and 10 in the HT group. The patients received 64.8 Gy to the bladder with or without concurrent chemotherapy. Conventional 4-field "box" pelvic radiation therapy (2DRT) plans were generated for comparison.</p> <p>Results</p> <p>The median patient age was 80 years old (range, 65-90 years old). The median survival was 21 months (5 to 26 months). The actuarial 2-year overall survival (OS) for the IMRT vs. the HT group was 26.3% <it>vs </it>.37.5%, respectively; the corresponding values for disease-free survival were 58.3% <it>vs</it>. 83.3%, respectively; for locoregional progression-free survival (LRPFS), the values were 87.5% <it>vs</it>. 83.3%, respectively; and for metastases-free survival, the values were 66.7% <it>vs</it>. 60.0%, respectively. The 2-year OS rates for T1, 2 <it>vs</it>. T3, 4 were 66.7% <it>vs</it>. 35.4%, respectively (<it>p </it>= 0.046). The 2-year OS rate was poor for those whose RT completion time greater than 8 weeks when compared with the RT completed within 8 wks (37.9% vs. 0%, <it>p </it>= 0.004).</p> <p>Conclusion</p> <p>IMRT and HT provide good LRPFS with tolerable toxicity for elderly patients with invasive bladder cancer. IMRT and HT dosimetry and organ sparing capability were superior to that of 2DRT, and HT provides better sparing ability than IMRT. The T category and the RT completion time influence OS rate.</p

    Combined Application Therapies of Stem Cells and Drugs in the Neurological Disorder Attenuation

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    Neurological disorders (NDs) are diseases of the central and peripheral nervous system that affected the hundreds of millions of people worldwide. Temporal lobe epilepsy (TLE) is a common NDs with hallucinations and disturbance of consciousness that cause the abnormal neurological activity in any part of brain. Neuroinflammation (NI) has been identified in epilepsy-related tissue from both experimental and clinical evidence and suspected to participate in the formation of neuronal cell death, reactive gliosis and neuroplastic changes in the hippocampus, may contribute to epileptogenesis. The NI is tightly regulated by microglia, but it is thought that excessive or chronic microglial activation can contribute to neurodegenerative processes. Therefore, the modulation of microglia responses may provide a therapeutic target for the treatment of severe or chronic NI conditions. Although the condition responds well to antiepileptic drugs (AEDs), there are still unresponsive to AEDs in about 1/3 of cases. Neural stem cells are the origin of various types of neural cells during embryonic development. Currently, many results of stem cell therapies in the animal experiments and clinical trials were demonstrated the efficacious therapeutic effects in the attenuated symptoms of ND. Therefore, the combined application therapies of stem cells and drugs may be a promising candidate for the therapeutic strategies of NDs, especially TLE

    Triggering Apoptotic Death of Human Malignant Melanoma A375.S2 Cells by Bufalin: Involvement of Caspase Cascade-Dependent and Independent Mitochondrial Signaling Pathways

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    Bufalin was obtained from the skin and parotid venom glands of toad and has been shown to induce cytotoxic effects in various types of cancer cell lines, but there is no report to show that whether bufalin affects human skin cancer cells. The aim of this investigation was to study the effects of bufalin on human malignant melanoma A375.S2 cells and to elucidate possible mechanisms involved in induction of apoptosis. A375.S2 cells were treated with different concentrations of bufalin for a specific time period and investigated for effects on apoptotic analyses. Our results indicated that cells after exposure to bufalin significantly decreased cell viability, and induced cell morphological changes and chromatin condensation in a concentration-dependent manner. Flow cytometric assays indicated that bufalin promoted ROS productions, loss of mitochondrial membrane potential (ΔΨm), intracellular Ca2+ release, and nitric oxide (NO) formations in A375.S2 cells. Additionally, the apoptotic induction of bufalin on A375.S2 cells resulted from mitochondrial dysfunction-related responses (disruption of the ΔΨm and releases of cytochrome c, AIF, and Endo G), and activations of caspase-3, caspase-8 and caspase-9 expressions. Based on those observations, we suggest that bufalin-triggered apoptosis in A375.S2 cells is correlated with extrinsic- and mitochondria-mediated multiple signal pathways
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