136 research outputs found
Preparation of Amidoxime Polyacrylonitrile Chelating Nanofibers and Their Application for Adsorption of Metal Ions.
Polyacrylonitrile (PAN) nanofibers were prepared by electrospinning and they were modified with hydroxylamine to synthesize amidoxime polyacrylonitrile (AOPAN) chelating nanofibers, which were applied to adsorb copper and iron ions. The conversion of the nitrile group in PAN was calculated by the gravimetric method. The structure and surface morphology of the AOPAN nanofiber were characterized by a Fourier transform infrared spectrometer (FT-IR) and a scanning electron microscope (SEM), respectively. The adsorption abilities of Cu2+ and Fe3+ ions onto the AOPAN nanofiber mats were evaluated. FT-IR spectra showed nitrile groups in the PAN were partly converted into amidoxime groups. SEM examination demonstrated that there were no serious cracks or sign of degradation on the surface of the PAN nanofibers after chemical modification. The adsorption capacities of both copper and iron ions onto the AOPAN nanofiber mats were higher than those into the raw PAN nanofiber mats. The adsorption data of Cu2+ and Fe3+ ions fitted particularly well with the Langmuir isotherm. The maximal adsorption capacities of Cu2+ and Fe3+ ions were 215.18 and 221.37 mg/g, respectively
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Transcriptional activation of CBFβ by CDK11p110 is necessary to promote osteosarcoma cell proliferation.
BACKGROUND:Aberrant expression of cyclin-dependent protein kinases (CDK) is a hallmark of cancer. CDK11 plays a crucial role in cancer cell growth and proliferation. However, the molecular mechanisms of CDK11 and CDK11 transcriptionally regulated genes are largely unknown. METHODS:In this study, we performed a global transcriptional analysis using gene array technology to investigate the transcriptional role of CDK11 in osteosarcoma. The promoter luciferase assay, chromatin immunoprecipitation assay, and Gel Shift assay were used to identify direct transcriptional targets of CDK11. Clinical relevance and function of core-binding factor subunit beta (CBFβ) were further accessed in osteosarcoma. RESULTS:We identified a transcriptional role of protein-DNA interaction for CDK11p110, but not CDK11p58, in the regulation of CBFβ expression in osteosarcoma cells. The CBFβ promoter luciferase assay, chromatin immunoprecipitation assay, and Gel Shift assay confirmed that CBFβ is a direct transcriptional target of CDK11. High expression of CBFβ is associated with poor outcome in osteosarcoma patients. Expression of CBFβ contributes to the proliferation and metastatic behavior of osteosarcoma cells. CONCLUSIONS:These data establish CBFβ as a mediator of CDK11p110 dependent oncogenesis and suggest that targeting the CDK11- CBFβ pathway may be a promising therapeutic strategy for osteosarcoma treatment
Effect of histamine-2-receptor antagonists versus sucralfate on stress ulcer prophylaxis in mechanically ventilated patients: a meta-analysis of 10 randomized controlled trials
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Correction to: Transcriptional activation of CBFβ by CDK11p110 is necessary to promote osteosarcoma cell proliferation.
Following publication of the original article [1], it was reported that Figs. 4 and 5 were not updated during the production process
Noninflammatory Changes of Microglia Are Sufficient to Cause Epilepsy.
Microglia are well known to play a critical role in maintaining brain homeostasis. However, their role in epileptogenesis has yet to be determined. Here, we demonstrate that elevated mTOR signaling in mouse microglia leads to phenotypic changes, including an amoeboid-like morphology, increased proliferation, and robust phagocytosis activity, but without a significant induction of pro-inflammatory cytokines. We further provide evidence that these noninflammatory changes in microglia disrupt homeostasis of the CNS, leading to reduced synapse density, marked microglial infiltration into hippocampal pyramidal layers, moderate neuronal degeneration, and massive proliferation of astrocytes. Moreover, the mice thus affected develop severe early-onset spontaneous recurrent seizures (SRSs). Therefore, we have revealed an epileptogenic mechanism that is independent of the microglial inflammatory response. Our data suggest that microglia could be an opportune target for epilepsy prevention
The role of clinically significant portal hypertension in hepatic resection for hepatocellular carcinoma patients: a propensity score matching analysis
An improved ARX model for hourly cooling load prediction of office buildings in different climates
An attempt was made to develop an improved autoregressive with exogenous (ARX) model for office buildings cooling load prediction in five major climates of China. The cooling load prediction methods can be arranged into three categories: regression analysis, energy simulation, and artificial intelligence. Among them, the regression analysis methods using regression models are much simple and practical for real applications. However, traditional regression models are often helpless to manage multiparameter dynamic changes, making it not accurate as the other two categories. Many of the existing cooling load prediction studies use piecewise linearization to manage nonlinearity. To improve the prediction accuracy of regression analysis methods, higher order and interaction terms are included in improved ARX based on traditional ARX model. The improved ARX model consists of eight variables, with eleven coefficients accessed at a time. For applications and evaluations, an office building in major cities within each climatic zone was selected as a representation. These cities were Harbin, Beijing, Nanjing, Kunming and Guangzhou respectively. The coefficient of determination R2 is greater than 0.9 in five cities. The prediction results show that the improved ARX model can adapt to different climatic conditions, including those nonlinearity cases
Memory-Efficient Searching of Gas-Chromatography Mass Spectra Accelerated by Prescreening
The number of metabolomics studies and spectral libraries for compound annotation (i.e., assigning possible compound identities to a fragmentation spectrum) has been growing steadily in recent years. Accompanying this growth is the number of mass spectra available for searching through those libraries. As the size of spectral libraries grows, accurate and fast compound annotation becomes more challenging. We herein report a prescreening algorithm that was developed to address the speed of spectral search under the constraint of low memory requirements. This prescreening has been incorporated into the Automated Data Analysis Pipeline Spectral Knowledgebase (ADAP-KDB) and can be applied to compound annotation by searching other spectral libraries as well. Performance of the prescreening algorithm was evaluated for different sets of parameters and compared to the original ADAP-KDB spectral search and the MSSearch software. The comparison has demonstrated that the new algorithm is about four-times faster than the original when searching for low-resolution mass spectra, and about as fast as the original when searching for high-resolution mass spectra. However, the new algorithm is still slower than MSSearch due to the relational database design of the former. The new search workflow can be tried out at the ADAP-KDB web portal
Combustion Performance of Methane/Air in a Micro Combustor Embedded Hollow Hemispherical Slotted Bluff Body
With the rapid development of micro-energy power systems, the performance of micro-combustors as key components is in urgent need of further improvement. Aimed at enhancing combustion performance, a hollow hemispherical bluff body was used to analyze the methane combustion process. In this paper, we exploited the detailed reaction mechanism of methane/air with a laminar finite-rate model; the numerical analysis of methane combustion in the micro-combustor was carried out by Ansys Fluent software. The combustion, flow and thermal characteristics of the micro-combustor embedded with a hollow hemisphere bluff body (MCEHB) and the micro combustor embedded with a slotted hollow hemisphere bluff body (MCESHB) are compared, and the effect of slot width ratio on the combustion characteristics and thermal performance is discussed in detail. The results showed that the bluff body slotting treatment is not only beneficial to improving the velocity and temperature distribution behind the bluff body but also can improve the conversion rate of methane, especially at high inlet velocities. However, the conversion rate of methane is also affected by the slot width. When the slot width ratio below 0.5, the slot width corresponding to the peak methane conversion increased with the inlet velocity. Moreover, the bluff body slotting treatment can improve the wall temperature distribution, meanwhile expanding the high temperature area at the inner wall, thereby reducing the wall temperature fluctuation in the rear part of the micro-combustor. In addition, the optimal slot width ratio B increases with the inlet velocity. Since the inlet velocity is lower than 0.5 m/s, the optimal slot width ratio B is in the range of 0.3–0.375. However, as the inlet velocity exceeds 0.5 m/s, the optimal slot width ratio B moves to the range of 0.375–0.553. Furthermore, both large and small slot widths bring obvious temperature fluctuations to the micro combustor; the uneven wall temperature distribution phenomenon is detrimental to working performance. Therefore, the slot width ratio B of 0.375 only brings slight temperature fluctuations, indicating this is an optimal slot width ratio that should be chosen. This work has reference value for optimizing the design of the bluff body structure and improving the combustion performance of methane in the micro combustor
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