Existence and uniqueness of positive solutions for Neumann problems of second order impulsive differential equations

This work is concerned with the existence and uniqueness of positive solutions for Neumann boundary value problems of second order impulsive differential equations. The result is obtained by using a fixed point theorem of generalized concave operators

LBH589 Inhibits proliferation and metastasis of hepatocellular carcinoma via inhibition of gankyrin/stat3/akt pathway

Background: Gankyrin has shown to be overexpressed in human liver cancers and plays a complex role in hepatocarcinogenesis. Panobinostat (LBH589), a new hydroxamic acid-derived histone deacetylase inhibitor has shown promising anticancer effects recently. Here, we investigated the potential of LBH589 as a form of treatment for hepatocellular carcinoma (HCC). Methods: Gankyrin plasmid was transfected into HCC cells, and the cells were selected for more than 4 weeks by incubation with G418 for overexpression clones. The therapeutic effects of LBH589 were evaluated in vitro and in vivo. Cell proliferation, apoptosis, cell cycle, invasive potential, and epithelial-mesenchy-mal transition (EMT) were examined. Results: LBH589 significantly inhibited HCC growth and metastasis in vitro and in vivo. Western blotting analysis indicated that LBH589 could decrease the expression of gankyrin and subsequently reduced serine-phosphorylated Akt and tyrosine-phosphorylated STAT3 expression although the total Akt and STAT3 were unaffected. LBH589 inhibited metastasis in vitro via down-regulation of N-cadherin, vimentin, TWIST1, VEGF and up-regulation of E-cadherin. LBH589 also induced apoptosis and G1 phase arrest in HCC cell lines. Ectopic expression of gankyrin attenuated the effects of LBH589, which indicates that gankyrin might play an important role in LBH589 mediated anticancer effects. Lastly, in vivo study indicated that LBH589 inhibited tumor growth and metastasis, without discernable adverse effects comparing to control group, with abrogating gankyrin/STAT3/Akt pathway. Conclusions: Our results suggested that LBH589 could inhibit HCC growth and metastasis through down-regulating gankyrin/STAT3/Akt pathway. LBH589 may present itself as a novel therapeutic strategy for HCC

Effect of Water on Mechanical Properties and Fracture Evolution of Fissured Sandstone under Uniaxial Compression: Insights from Experimental Investigation

AbstractPreexisting discontinuities and the water affect the fracture evolution process as well as the rock stability the most extensively. To ensure operational safety, the effects of water on the mechanical properties of fissured rock masses must be understood well. In this study, a series of uniaxial compressive tests is conducted on both dry and saturated fissured specimens with varying fissure angles. Real-time acoustic emission and digital image correlation are applied to monitor the fracture evolution process. The failure mode is investigated by identifying the types of cracks present in the ultimate failure forms of the fissured specimens. The results indicate that (1) the saturated and dry specimens exhibit significantly different strengths and stiffnesses, wherein the saturated specimens exhibit weaker strength by 25.64%–32.59% and a lower elastic modulus by 20.30%–29.22%. (2) The fissure angle and water jointly control the failure mode of fissured sandstone. (3) The observed fracture evolution processes can be classified into six distinct stages to facilitate the understanding of rock failure mechanisms. (4) The presence of water accelerates the nucleation of microcracks at the tips of the prefabricated fissures, enlarges the range of microcrack coalescence, and facilitates the emergence of unstable cracks owing to an increase in pore water pressure and a decrease in the friction resistance of crack surfaces

3D printing of bone and cartilage with polymer materials

Damage and degeneration to bone and articular cartilage are the leading causes of musculoskeletal disability. Commonly used clinical and surgical methods include autologous/allogeneic bone and cartilage transplantation, vascularized bone transplantation, autologous chondrocyte implantation, mosaicplasty, and joint replacement. 3D bio printing technology to construct implants by layer-by-layer printing of biological materials, living cells, and other biologically active substances in vitro, which is expected to replace the repair mentioned above methods. Researchers use cells and biomedical materials as discrete materials. 3D bio printing has largely solved the problem of insufficient organ donors with the ability to prepare different organs and tissue structures. This paper mainly discusses the application of polymer materials, bio printing cell selection, and its application in bone and cartilage repair

Effects of Understory Vegetation Heterogeneity on Soil Organic Carbon Components in <i>Cunninghamia lanceolata</i> Plantation

As one of the important factors affecting forest soil organic carbon stocks, the effect of understory vegetation types on soil organic carbon and its components was explored to provide a theoretical basis for understory vegetation management and sustainable management in plantation forests. In order to determine the characteristics of soil organic carbon and its components under different understory vegetation types in Subtropical Cunninghamia lanceolata plantation, Indocalamus tessellatus, Diplazium donianum and Oreocnide frutescenssp were taken as research objects. The mass fractions of total organic carbon, recalcitrant organic carbon, readily oxidizable organic carbon, microbial biomass carbon and dissolved organic carbon in each soil layer at 0–10, 10–20, 20–40 and 40–60 cm were measured, and the change characteristics of soil organic carbon components were also studied and compared. The results showed that: (1) The mass fractions of total organic carbon, recalcitrant organic carbon, readily oxidizable organic carbon and microbial biomass carbon in the soils of the three understory vegetation types showed significant decreasing trends along the profile, while the mass fraction of dissolved organic carbon in 0–40 cm soil layer was significantly higher than those in 40–60 cm soil layer. (2) The mass fraction of total organic carbon (5.98–20.66 g·kg−1) had no significant difference among understory vegetation types. The mass fraction and proportion of microbial biomass carbon were higher in the 0–60 cm soil layer under cover of Indocalamus tessellatus, and the mass fractions of recalcitrant organic carbon in the 20–40 cm soil layer under Indocalamus tessellatus cover (8.57 g·kg−1) was significantly higher than that of Oreocnide frutescenssp (5.73 g·kg−1). The soil layer of 0–20 cm under the Diplazium donianum community has a higher mass fraction and proportion of readily oxidizable organic carbon. (3) Correlation analysis showed that soil organic carbon and its components were positively correlated with total nitrogen, dissolved total nitrogen, dissolved organic nitrogen and microbial biomass nitrogen. There is a significant positive correlation among the components of soil organic carbon. (4) Redundancy analysis showed that soil bulk density (41.6%), microbial biomass nitrogen (41.2%), dissolved total nitrogen (43.7%), total nitrogen (9.9%), dissolved organic nitrogen (43.6%) and pH (6.6%) were the most significant environmental factors affecting organic carbon components in four soil layers. Understory vegetation type can influence the distribution characteristics of soil organic carbon components in Cunninghamia lanceolata plantation, and soil active organic carbon components are more susceptible to the influence of understory vegetation type than total organic carbon and recalcitrant organic carbon

Preparation of a Novel Solid Phase Microextraction Fiber for Headspace GC-MS Analysis of Hazardous Odorants in Landfill Leachate

The practice of odorant analysis can often be very challenging because odorants are usually composed of a host of volatile organic compounds (VOCs) at low concentrations. Preconcentration with solid phase microextraction (SPME) is a conventional technique for the enrichment of these volatile compounds before analysis by headspace gas chromatography-mass spectrometry (GC-MS). However, commercially available SPME products usually bear the defects of weak mechanical strength and high cost. In this work, novel SPME fibers were prepared by a one-pot synthesis procedure from divinylbenzene (DVB), porous carbon powder (Carbon) and polydimethylsiloxane (PDMS). Factors that influence the extraction efficiency, such as extraction temperature, extraction time, salting effects, pH, stirring rate, desorption temperature and time, were optimized. VOCs in landfills pose a great threat to human health and the environment. The new SPME fibers were successfully applied in the analysis of VOCs from the leachate of a cyanobacteria landfill. Quantification methods of major odor contributors were established, and a good linearity (r &gt; 0.998) was obtained, with detection limits in the range of 0.30&ndash;0.50 ng/L. Compared to commercial SPME fibers, the new material has higher extraction efficacy and higher precision. Hence, it is suitable for the determination of hazardous odorants of various sources

Effects of Understory Vegetation Heterogeneity on Soil Organic Carbon Components in Cunninghamia lanceolata Plantation

As one of the important factors affecting forest soil organic carbon stocks, the effect of understory vegetation types on soil organic carbon and its components was explored to provide a theoretical basis for understory vegetation management and sustainable management in plantation forests. In order to determine the characteristics of soil organic carbon and its components under different understory vegetation types in Subtropical Cunninghamia lanceolata plantation, Indocalamus tessellatus, Diplazium donianum and Oreocnide frutescenssp were taken as research objects. The mass fractions of total organic carbon, recalcitrant organic carbon, readily oxidizable organic carbon, microbial biomass carbon and dissolved organic carbon in each soil layer at 0&ndash;10, 10&ndash;20, 20&ndash;40 and 40&ndash;60 cm were measured, and the change characteristics of soil organic carbon components were also studied and compared. The results showed that: (1) The mass fractions of total organic carbon, recalcitrant organic carbon, readily oxidizable organic carbon and microbial biomass carbon in the soils of the three understory vegetation types showed significant decreasing trends along the profile, while the mass fraction of dissolved organic carbon in 0&ndash;40 cm soil layer was significantly higher than those in 40&ndash;60 cm soil layer. (2) The mass fraction of total organic carbon (5.98&ndash;20.66 g&middot;kg&minus;1) had no significant difference among understory vegetation types. The mass fraction and proportion of microbial biomass carbon were higher in the 0&ndash;60 cm soil layer under cover of Indocalamus tessellatus, and the mass fractions of recalcitrant organic carbon in the 20&ndash;40 cm soil layer under Indocalamus tessellatus cover (8.57 g&middot;kg&minus;1) was significantly higher than that of Oreocnide frutescenssp (5.73 g&middot;kg&minus;1). The soil layer of 0&ndash;20 cm under the Diplazium donianum community has a higher mass fraction and proportion of readily oxidizable organic carbon. (3) Correlation analysis showed that soil organic carbon and its components were positively correlated with total nitrogen, dissolved total nitrogen, dissolved organic nitrogen and microbial biomass nitrogen. There is a significant positive correlation among the components of soil organic carbon. (4) Redundancy analysis showed that soil bulk density (41.6%), microbial biomass nitrogen (41.2%), dissolved total nitrogen (43.7%), total nitrogen (9.9%), dissolved organic nitrogen (43.6%) and pH (6.6%) were the most significant environmental factors affecting organic carbon components in four soil layers. Understory vegetation type can influence the distribution characteristics of soil organic carbon components in Cunninghamia lanceolata plantation, and soil active organic carbon components are more susceptible to the influence of understory vegetation type than total organic carbon and recalcitrant organic carbon

Working memory inspired hierarchical video decomposition with transformative representations

Video decomposition is very important to extract moving foreground objects from complex backgrounds in computer vision, machine learning, and medical imaging, e.g., extracting moving contrast-filled vessels from the complex and noisy backgrounds of X-ray coronary angiography (XCA). However, the challenges caused by dynamic backgrounds, overlapping heterogeneous environments and complex noises still exist in video decomposition. To solve these problems, this study is the first to introduce a flexible visual working memory model in video decomposition tasks to provide interpretable and high-performance hierarchical deep architecture, integrating the transformative representations between sensory and control layers from the perspective of visual and cognitive neuroscience. Specifically, robust PCA unrolling networks acting as a structure-regularized sensor layer decompose XCA into sparse/low-rank structured representations to separate moving contrast-filled vessels from noisy and complex backgrounds. Then, patch recurrent convolutional LSTM networks with a backprojection module embody unstructured random representations of the control layer in working memory, recurrently projecting spatiotemporally decomposed nonlocal patches into orthogonal subspaces for heterogeneous vessel retrieval and interference suppression. This video decomposition deep architecture effectively restores the heterogeneous profiles of intensity and the geometries of moving objects against the complex background interferences. Experiments show that the proposed method significantly outperforms state-of-the-art methods in accurate moving contrast-filled vessel extraction with excellent flexibility and computational efficiency