180 research outputs found
Variation of adsorption effects in coals with different particle sizes induced by differences in microscopic adhesion
Acknowledgements This research was funded by the National Natural Science Foundation of China (grant nos. 41830427, 42130806 and 41922016), the Fundamental Research Funds for Central Universities (grant no. 2-9-2021-067) and the 2021 Graduate Innovation Fund Project of China University of Geosciences, Beijing (grant no. ZD2021YC035). We are very grateful to the reviewers and editors for their valuable comments and suggestionsPeer reviewedPostprin
Blockage of transdifferentiation from fibroblast to myofibroblast in experimental ovarian cancer models
<p>Abstract</p> <p>Background</p> <p>Tumour stromal myofibroblasts can promote tumour invasion. As these cells are genetically more stable than cancer cells, there has been enormous interest in developing targeted molecular therapies against them. Chloride intracellular channel 4 (CLIC4) and reactive oxygen species (ROS) have been linked with promoting stromal cell transdifferentiation in various cancers, but little is known of their roles in ovarian cancer. In this study, we examined the functional roles that both CLIC4 and ROS play in the process of ovarian cancer cell-stimulated or TGF-β1 induced fibroblast-to-myofibroblast transdifferentiation. We also examine whether it is possible to reverse such a process, with the aim of developing novel therapies against ovarian cancer by targeting activated transdifferentiated myofibroblasts.</p> <p>Results</p> <p>We demonstrate that TGF-β1 induced or CM<sup>SKOV3 </sup>activate transdifferentiated myofibroblasts (fibroblasts). These fibroblasts mimic "reactive" stromal myofibroblasts and demonstrate significant up-regulation of CLIC4 expression and increased level of ROS production. Blocking the production of ROS with an antioxidant consequently reduces the expression of CLIC4, and is accompanied by disappearance of <it>α</it>-smooth-muscle actin (α-SMA), a myofibroblast marker, suggesting ROS acts as a signalling molecule that promotes and enhances CLIC4 activities in the myofibroblast transdifferentiaton process. Down-regulation of CLIC4 with a generic agent or specific siRNA both significantly reduces the expression of factors related to the phenotypes and functions of myofibroblasts, such as α-SMA, hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), thus reversing the myofibroblast phenotype back to fibroblasts. These results convincingly show that ROS and CLIC4 are responsible for TGF-β1 induced fibroblast-to-myofibroblast transdifferentiaton and down-regulation of both is sufficient to block transdifferentiated myofibroblasts.</p> <p>Conclusion</p> <p>Molecular targeting of ROS and CLIC4 has the potential to develop novel therapies for ovarian cancer.</p
Superior surface modification layer of poly(styrene) on SiO gate insulator in rubrene single crystal field-effect transistor
We conduct comparative research on the density of states of electron- and
hole- carrier trap levels (DTR(E)), dispersing inside the energy gap of a
rubrene single crystal in a field effect transistor (FET) struction with Ca and
Au hetero-electrodes for an ambipolar carrier injection mode, by using
polymeric protection-layer materials on a Si substrate. Three different types
of polymeric materials, poly(methyl-methacrylate) (PMMA), poly(styrene) (PS)
and poly(chloro-styrene) (PCS) are employed. From the temperature (T)-dependent
source-drain current and gate voltage (ISD-VG) transfer characteristics, the
values of DTR(E) are evaluated. PS exhibits the most efficiently-balanced
ambipolar carrier transport, which is superior to PMMA that is most typically
used as the standard protection layer on a SiO/doped-Si substrate.
Discussions are made in the framework of a carrier multiple trap and release
(CMTR) model.Comment: 9 pages, 5figure
Enhanced spin-orbit coupling in hydrogenated and fluorinated graphenes studied from first principles
The spin-orbit couplings (SOCs) of hydrogenated and fluorinated graphenes are
calculated from the first principles method. It is found that the SOC-induced
band splittings near their Fermi energies can be significantly enhanced to the
order of 10 eV from the original about 10 eV of the pure raphene,
which is comparable to those found in the diamond and even the archetypal
semiconductors. And two different mechanisms are proposed to explain the SOC
enhancements in these two systems. The huge SOC enhancements are found to come
not only from the sp hybridization of carbon atoms, but also from the
larger intrinsic SOC of the fluorine atom than the carbon one. We hope many
interesting phenomena caused by the SOCs (e.g. the spin Hall effect) can be
observed experimentally in these systems.Comment: 9 pages, 3 figures, and 1 tabl
Nutrient limitation of woody debris decomposition in a tropical forest:contrasting effects of N and P addition
1.Tropical forests represent a major terrestrial store of carbon (C), a large proportion of which is contained in the soil and decaying organic matter. Woody debris plays a key role in forest C dynamics because it contains a sizeable proportion of total forest C. Understanding the factors controlling the decomposition of organic matter in general, and woody debris in particular, is hence critical to assessing changes in tropical C storage. 2.We conducted a factorial fertilization experiment in a tropical forest in South China to investigate the influence of nitrogen (N) and phosphorus (P) availability onwoody debris decomposition using branch segments (5-cm diameter) of four species (Acacia auriculaeformis, Aphanamixis polystachya, Schefflera octophylla, Carallia brachiata) in plots fertilized with +N, +P, or +NP, and controls. 3.Fertilization with +P and +NP increased decomposition rates by 5-53% and the magnitude was species-specific. Contrary to expectations, we observed no negative effect of +N addition on decay rates or mass loss of woody debris in any of the four study species. Decomposition rates of woody debris were higher in species with lower C:P ratios regardless of treatment. 4.We observed significant accumulation of P in the woody debris of all species in plots fertilized with +P and +NP during the early stages of decomposition. N-release from woody debris of Acacia (N-fixing) was greater in the +P plots towards the end of the study, whereas fertilization with +N had no impact on the patterns of nutrient release during decomposition. 5.Synthesis: Our results indicate that decomposition of woody debris is primarily constrained by P availability in this tropical forest. However, contrary to expectations, +N addition did not exacerbate P-limitation. It is conceivable that decay rates of woody debris in tropical forests can be predicted by C:P or lignin:P ratios but additional work with more tree species is needed to determine whether the patterns we observed are more generally applicable
Reforestation in southern China: revisiting soil N mineralization and nitrification after 8 years restoration
Nitrogen availability and tree species selection play important roles in reforestation. However, long-term field studies on the effects and mechanisms of tree species composition on N transformation are very limited. Eight years after tree seedlings were planted in a field experiment, we revisited the site and tested how tree species composition affects the dynamics of N mineralization and nitrification. Both tree species composition and season significantly influenced the soil dissolved organic carbon (DOC) and nitrogen (DON). N-fixing Acacia crassicarpa monoculture had the highest DON, and 10-mixed species plantation had the highest DOC. The lowest DOC and DON concentrations were both observed in Eucalyptus urophylla monoculture. The tree species composition also significantly affected net N mineralization rates. The highest rate of net N mineralization was found in A. crassicarpa monoculture, which was over twice than that in Castanopsis hystrix monoculture. The annual net N mineralization rates of 10-mixed and 30-mixed plantations were similar as that of N-fixing monoculture. Since mixed plantations have good performance in increasing soil DOC, DON, N mineralization and plant biodiversity, we recommend that mixed species plantations should be used as a sustainable approach for the restoration of degraded land in southern China
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