218 research outputs found
Research Progress of Anti-tumor Active Ingredients in Dandelion
As a traditional Chinese herb, dandelion, containing complicated activeingredients which includes polysaccharide, flavonoid, terpene, pigment,phytosterol, coumarin, organic acid and etc, plays significant roles invarious physiological activities in organisms. The active ingredientsgenerally interfere in signal transduction of cancer cells, regulate cellcycle and apoptotic protein expression, inhibit cancer cells proliferationand migration and etc, which effectively restrains tumor developmentand deterioration. This article summarizes the anti-tumor mechanism offive active ingredients in dandelion through paper reading which providesthoughts and references for anti-tumor research
Load-balancing distributed outer joins through operator decomposition
High-performance data analytics largely relies on being able to efficiently execute various distributed data operators such as distributed joins. So far, large amounts of join methods have been proposed and evaluated in parallel and distributed environments.
However, most of them focus on inner joins, and there is little published work providing the detailed implementations and analysis
of outer joins. In this work, we present POPI (Partial Outer join & Partial Inner join), a novel method to load-balance large parallel
outer joins by decomposing them into two operations: a large outer join over data that does not present significant skew in the input
and an inner join over data presenting significant skew. We present the detailed implementation of our approach and show that
POPI is implementable over a variety of architectures and underlying join implementations. Moreover, our experimental evaluation
over a distributed memory platform also demonstrates that the proposed method is able to improve outer join performance under
varying data skew and present excellent load-balancing properties, compared to current approaches
SIRT6 protects against palmitate-induced pancreatic β-cell dysfunction and apoptosis
Chronic exposure of pancreatic β-cells to abnormally elevated levels of free fatty acids can lead to β-cell dysfunction and even apoptosis, contributing to type 2 diabetes pathogenesis. In pancreatic β-cells, SIRT6 has been shown to regulate insulin secretion in response to glucose stimulation. However, what roles SIRT6 play in β-cells in response to lipotoxicity remain poorly understood. Our data indicated that SIRT6 protein and mRNA levels were reduced in islets from diabetic and aged mice. High concentrations of palmitate also led to a decrease in SIRT6 expression in MIN6 β-cells and resulted in cell dysfunction and apoptosis. Knockdown of Sirt6 caused an increase in cell apoptosis and impairment in insulin secretion in response to glucose in MIN6 cells even in the absence of high palmitate. Furthermore, overexpression of SIRT6 alleviated the palmitate-induced lipotoxicity with improved cell viability and increased glucose-stimulated insulin secretion. In summary, our data suggest that SIRT6 can protect against palmitate-induced β-cell dysfunction and apoptosis
Strand-specific PCR of UV radiation-damaged genomic DNA revealed an essential role of DNA-PKcs in the transcription-coupled repair
<p>Abstract</p> <p>Background</p> <p>In eukaryotic cells, there are two sub-pathways of nucleotide excision repair (NER), the global genome (gg) NER and the transcription-coupled repair (TCR). TCR can preferentially remove the bulky DNA lesions located at the transcribed strand of a transcriptional active gene more rapidly than those at the untranscribed strand or overall genomic DNA. This strand-specific repair in a suitable restriction fragment is usually determined by alkaline gel electrophoresis followed by Southern blotting transfer and hybridization with an indirect end-labeled single-stranded probe. Here we describe a new method of TCR assay based on strand-specific-PCR (SS-PCR). Using this method, we have investigated the role of DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a member of the phosphatidylinositol 3-kinase-related protein kinases (PIKK) family, in the TCR pathway of UV-induced DNA damage.</p> <p>Results</p> <p>Although depletion of DNA-PKcs sensitized HeLa cells to UV radiation, it did not affect the ggNER efficiency of UV-induced cyclobutane pyrimidine dimers (CPD) damage. We postulated that DNA-PKcs may involve in the TCR process. To test this hypothesis, we have firstly developed a novel method of TCR assay based on the strand-specific PCR technology with a set of smart primers, which allows the strand-specific amplification of a restricted gene fragment of UV radiation-damaged genomic DNA in mammalian cells. Using this new method, we confirmed that siRNA-mediated downregulation of Cockayne syndrome B resulted in a deficiency of TCR of the UV-damaged dihydrofolate reductase (<it>DHFR</it>) gene. In addition, DMSO-induced silencing of the c-myc gene led to a decreased TCR efficiency of UV radiation-damaged c-myc gene in HL60 cells. On the basis of the above methodology verification, we found that the depletion of DNA-PKcs mediated by siRNA significantly decreased the TCR capacity of repairing the UV-induced CPDs damage in <it>DHFR </it>gene in HeLa cells, indicating that DNA-PKcs may also be involved in the TCR pathway of DNA damage repair. By means of immunoprecipitation and MALDI-TOF-Mass spectrometric analysis, we have revealed the interaction of DNA-PKcs and cyclin T2, which is a subunit of the human transcription elongation factor (P-TEFb). While the P-TEFb complex can phosphorylate the serine 2 of the carboxyl-terminal domain (CTD) of RNA polymerase II and promote transcription elongation.</p> <p>Conclusion</p> <p>A new method of TCR assay was developed based the strand-specific-PCR (SS-PCR). Our data suggest that DNA-PKcs plays a role in the TCR pathway of UV-damaged DNA. One possible mechanistic hypothesis is that DNA-PKcs may function through associating with CyclinT2/CDK9 (P-TEFb) to modulate the activity of RNA Pol II, which has already been identified as a key molecule recognizing and initializing TCR.</p
Mesenchymal Stem Cell Transplantation for Liver Cell Failure: A New Direction and Option
Background and Aims. Mesenchymal stem cell transplantation (MSCT) became available with liver failure (LF), while the advantages of MSCs remain controversial. We aimed to assess clinical advantages of MSCT in patients with LF. Methods. Clinical researches reporting MSCT in LF patients were searched and included. Results. Nine articles (n=476) related with LF patients were enrolled. After MSCT, alanine aminotransferase (ALT) baseline decreased largely at half a month (P<0.05); total bilirubin (TBIL) baseline declined to a certain stable level of 78.57 μmol/L at 2 and 3 months (P<0.05). Notably, the decreased value (D value) of Model for End-Stage Liver Disease score (MELD) of acute-on-chronic liver failure (ACLF) group was higher than that of chronic liver failure (CLF) group (14.93 ± 1.24 versus 4.6 ± 5.66, P<0.05). Moreover, MELD baseline of ≥20 group was a higher D value of MELD than MELD baseline of <20 group with a significant statistical difference after MSCT (P=0.003). Conclusion. The early assessment of the efficacy of MSCT could be based on variations of ALT at half a month and TBIL at 2 and 3 months. And it had beneficial effects for patients with LF, especially in ACLF based on the D value of MELD
MPC-CSAS: multi-party computation for real-time privacy-preserving speed advisory systems
As a part of Advanced Driver Assistance Systems (ADASs), Consensus-based Speed Advisory Systems (CSAS) have been proposed to recommend a common speed to a group of vehicles for specific application purposes, such as emission control and energy management. With Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) technologies and advanced control theories in place, state-of-the-art CSAS can be designed to get an optimal speed in a privacy-preserving and decentralized manner. However, the current method only works for specific cost functions of vehicles and its execution usually involves many algorithm iterations leading long convergence time. Therefore, the state-of-the-art design method is not applicable to a CSAS design which requires real-time decision making. In this paper, we address the problem by introducing MPC-CSAS, a Multi-Party Computation (MPC) based design approach for privacy-preserving CSAS. Our proposed method is simple to implement and applicable to all types of cost functions of vehicles. Moreover, our simulation results show that the proposed MPC-CSAS can achieve very promising system performance in just one algorithm iteration without using extra infrastructure for a typical CSAS
Effects of Normal Stress and Joint Inclination Angle on Rock Failure Characteristics Under Compression–Shear Conditions
In this study, cement mortar was used to make specimens containing groups of parallel joints with different inclination angles to simulate natural rock mass, and the specimens were subjected to shear tests under different normal stresses. By analyzing the crack propagation path, failure modes, and strength characteristics of these rock specimens, the effects of normal stress and joint inclination angles on the strength and failure characteristics of this type of rock mass were studied. The following conclusions are drawn: 1) when the inclination angles of the joints are 0° and 15°, the changing of the normal stress did not affect the failure mode of the rock mass. The rock mass was mainly in the mode of shear failure, and the increase in the normal stress only increased the spalling area of the rock mass. 2) When the inclination angles of the joints are 30°, 45°, and 60°, with the increasing of the normal stress, the number of those approximately parallel cracks in the specimens increased, the friction marks caused by shearing increased, and the failure mode of the rock mass changed from tension failure to tension–shear composite failure. 3) Under different joint inclination angles, the propagation and penetration paths of cracks generated in the rock mass and the damage mode of the rock mass were different. With an increase in the joint inclination angles, the damage mode of the rock mass gradually changes from shear damage to tensile–shear composite damage and the α and β angles between the through cracks and the vertical direction on the left and right sides of the specimens tended to decrease. 4) The shear resistance of the rock mass was affected by the inclination angle of the joints and the normal pressure. The shear resistance of rock mass was improved due to the increasing of normal stress. Within a certain range, with the increasing of the inclination angles of the joint, the shear resistance of the rock mass tended to decrease first and then to increase
Eco-physiological response mechanism of Tamarix chinensis to soil water changes in coastal wetlands of the Yellow River Delta
Elucidating the effect of soil moisture on the adaptation of dominant plants in coastal wetlands is important for predicting the evolution of vegetation in the region. In this paper, Tamarix chinensis, a dominant species in the Yellow River Delta, was used as the object to study the changes of its growth and physiological parameters with increasing soil salinity under different moisture conditions (normal watering, persistent drought and persistent waterlogging). Different salt stress (2‰, 5‰, 8‰, 12‰, 16‰, and 20‰) using pot experiments was also used to reveal the mechanism of soil moisture on its salt tolerance. The results showed that the relative growth rate between 5‰-8‰ soil salinity was the largest, and growth was significantly inhibited above 20‰. Among different moisture conditions, the difference in relative growth rate under normal watering and persistent drought were nonsignificant, while both were significantly lower than those under persistent waterlogging. With increasing soil salinity, relative water content and total chlorophyll content significantly decreased, and cell membrane permeability (malondialdehyde), sodium ion, osmoregulatory substances (proline, soluble protein), and protective enzyme activity (SOD) significantly increased, while changes in non-structural carbohydrates (NSC) were not significant. Compared with normal watering and persistent waterlogging, persistent drought had the lowest leaf relative water content, total chlorophyll content, and sodium ions, and the highest cell membrane permeability, osmoregulatory substances and protective enzyme activity. With increasing treatment time, the relative leaf water content and total chlorophyll content significantly decreased, and cell membrane permeability, osmoregulatory substances and protective enzyme activity increased more significantly than normal watering and persistent waterlogging. NSC increased under normal watering and persistent waterlogging, while significantly decreased under persistent drought. Correlation analysis showed that the relationships between sodium ions, total chlorophyll content and malondialdehyde were various under different moisture conditions. Under persistent drough, malondialdehyde was significantly positively correlated with relative conductivity, superoxide dismutase, proline, soluble protein and soluble sugar. Total chlorophyll content was the key indicator reflecting the salt and waterlogging tolerance of T. chinensis under normal watering and persistent waterlogging, while cell membrane damage was under persistent drought. In summary, T. chinensis has strong salt and waterlogging tolerance, but persistent drought with salt stress can have serious impacts on its growth and survival
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