Landfill stabilized waste (LSW) is the aged municipal solid waste mined from old landfills. It is a soil-like material containing high value of organic matter and nutrients and thus may be used as ...topsoil substitute. To evaluate the potential harmful effects, LSW was sampled from five landfills around Beijing, China. The concentration of 150 semi-volatile organic compounds (SVOCs), total soluble salt, cation exchange capacity (CEC) and the distribution of water-stable aggregate size fractions were determined. According to the results, 14 SVOCs were detected in LSW, including phenol, cresol, 9 PAHs, 2 PAEs and 1 OCP. The concentrations of all detected SVOCs were below the critical limits for soil quality published by Chinese authority, but further studies are needed when it is applied in areas for residential use. The total soluble salt content of LSW ranged from 2.9 to 7.6 g kg
−1
, and CEC ranged from 3.13 to 6.06 cmol kg
−1
, indicating that LSW had a high level of salinity but a poor ability of holding and releasing positive-charged elements by clay minerals and humus colloids. Compared to agricultural soil (sandy clay), LSW had more and larger water-stable aggregates, and generally, plants grew better in LSW. LSW of 7–10 mm in size was best for plant growth. The results confirm LSW as a promising topsoil substitute which can be used in afforestation.
Spinal cord injury (SCI) causes severe neural tissue damage and motor/sensory dysfunction. Since the injured spinal cord tissue has limited self-regeneration ability, several strategies, including ...cell therapy, drug delivery, and tissue engineering scaffold implantation, have been employed to treat SCI. However, each of these strategies fails to obtain desirable outcomes due to their respective limitations. In comparison, advanced tissue engineering scaffolds with appropriate topographical features, favorable composition, and sustained drug delivery capability can be employed to recruit endogenous neural stem cells (NSCs), induce neuronal differentiation, and facilitate neuron maturation. This can lead to the regeneration of injured spinal cord tissue and the recovery of motor function. In this study, fiber bundle-reinforced spinal cord extracellular matrix hydrogel scaffolds loaded with oxymatrine (OMT) were produced through nearfield direct write electrospinning. The spinal cord extracellular matrix-based hydrogel was then coated with OMT. The physical/chemical properties and in vitro degradation behavior of the composite scaffolds were investigated. The in vitro cell culture results showed that composite scaffolds loaded with OMT promoted the differentiation of NSCs into neurons and inhibited differentiation into astrocytes. The in vivo results showed that the composite scaffolds loaded with OMT recruited NSCs from the host tissue, promoted neuronal differentiation and axon extension at the lesion site, inhibited glial scar formation at/around the lesion site, and improved the recovery of motor function in rats with SCI. To sum up, 3D-printed microfiber-reinforced spinal cord extracellular matrix hydrogel scaffolds loaded with OMT are promising biomaterials for the treatment of SCI.
Multiple forging cycles are required to reach a steady-state temperature distribution in forging dies, which can lead to thermoelastic deformation and impact on the dimensional accuracy of the final ...forging components. The steady-state temperature fields of a three-layer combined die with constant, convection, conduction and convection thermal boundary conditions were determined in the present study. Thermoelastic deformation and the contact stresses between layers were directly related to geometric and material properties, external stresses and the temperature distribution. Warm/hot and cold forging case studies were studied using finite-element analysis. In warm/hot forging, the contact stress of the steady-state temperature distribution was smaller than the hypothetical non-uniform temperature distribution. During cold forging, the difference in total deformation between steady-state and uniform temperature distributions at the same temperature was 0.025 mm, which may reduce the geometrical accuracy of cold forging parts.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Glioma stem cells (GSCs) are considered the source for development, recurrence, and poor prognosis of glioma, so treatment targeted GSCs is of great interest. The frequently rearranged in advanced T ...cell lymphomas-1 (FRAT1) gene is an important member of the Wnt/β-catenin signaling transduction pathway, and aberrantly activation of Wnt signaling has been identified to contribute to the tumorigenesis, proliferation, invasion of a variety kinds of cancer stem cells. However, correlations between FRAT1 and GSCs and the specific mechanisms remain unclear. In this study, we aimed to investigate the effect of FRAT1 on GSCs proliferation, colony formation, sphere formation and tumorigenesity in vitro and in vivo and its underlying mechanism. Lentiviral transfection was used to construct GSCs with low FRAT1 expression. The expression of FRAT1 on GSCs proliferation in vitro was assessed by cell counting kit-8(CCK-8). Colony formation and sphere formation assays were conducted to assess the colony and sphere formation ability of GSCs. Then, an intracranial glioma nude mouse model was built to measure the effect of low FRAT1 expression on GSCs proliferation and tumorigenesity in vivo. Real-time PCR, Western blot, and Immunohistochemistry were processed to detect the mRNA and protein expressions of FRAT1, β-catenin in the glioma tissue of xenograft mice to study their correlations. The functional assays verifed that low FRAT1 expression inhibited CD133
Nestin
GSCs proliferation, colony formation, sphere formation ability in vitro. In vivo GSCs xenograft mice model showed that low FRAT1 expression suppressed the proliferation and tumorigenesity of CD133
Nestin
GSCs and reduced β-catenin mRNA and protein expression. Furthermore, the expression of FRAT1 and β-catenin were positively correlated. Altogether, results indicate that FRAT1 enhances the proliferation, colony formation, sphere formation and tumorigenesity of CD133
Nestin
glioma stem cells in vitro and in vivo as well as the expression of β-catenin. Therefore, inhibiting proliferation of GSCs and FRAT1 may be a molecular target to GSCs in treating human glioma in the future.
In this study, the α-Fe
2
O
3
nanoparticles were successfully fabricated by chemical method. Smelting technique has been used to prepare the Sn–1.0Ag–0.7Cu–xFe
2
O
3
composite solders, while the ...weight percent of α-Fe
2
O
3
in the solders ranged from 0 to 1 wt%. The influences of α-Fe
2
O
3
nanoparticles on microstructure, melting temperature, microhardness, and coefficient of thermal expansion (CTE) of the composite solders and on mechanical properties of the composite solders joints were investigated. The results indicate that added α-Fe
2
O
3
nanoparticles can remarkably improve the Vickers microhardness of the composite solders and decrease the CTE of composite solders, while the melting temperature of the composite solders have no obvious change, compared to the original Sn–1.0Ag–0.7Cu solder. The shear strength and tensile strength of the solder joints will be increased firstly and then decreased with the increasing of α-Fe
2
O
3
in the composite solders. And the Sn–1.0Ag–0.7Cu–0.4Fe
2
O
3
solder joint possesses the best shear strength and tensile strength.
Deformation behavior was investigated in detail from cold extrusion and upsetting tests on medium carbon steel. A new "cold forging after quenching and tempering" (CFAQT) process was proposed. ...Compared with conventional processes, including annealing before cold forging, plus quenching and tempering after forging, the CFAQT process could shorten the process chain and avoid subsequent heat treatment distortion with clear energy-saving and cost-reduction benefits. The CFAQT process was applied successfully in the mass production of a lock set for industrial automobile wheels and in laboratory spline extrusions.
An intrinsic high‐barrier polyimide (2,7‐CPAPPI) containing rigid planar carbazole moiety and amide group in main chain was prepared. The 2,7‐CPAPPI shows very attractive barrier performances, ...possessing water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) low to 0.04 g m−2 day−1 and 0.11 cm3 m−2 day−1, respectively. Meanwhile, 2,7‐CPAPPI also displays exceptional thermal stability with a glass transition temperature (Tg) of 552°C and coefficient of thermal expansion (CTE) of 15.48 ppm/K. The barrier performances of 2,7‐CPAPPI are compared with those of a structural analog (2,7‐CPPI, containing only carbazole moiety in the main chain) and a typical polyimide (Kapton). The structure–barrier performances relationship was investigated by molecular simulations, wide angle X‐ray diffraction (WAXD), and positron annihilation lifetime spectroscopy (PALS). The results show that 2,7‐CPAPPI has more number of intermolecular hydrogen bonds among the three PIs, which leads to close chain packing and thereby high crystallinity, low free volume, and poor chains mobility. That is, the high crystallinity and low free volume of 2,7‐CPAPPI decrease the diffusion and solubility of gases. Meanwhile, the poor chains mobility further reduces the gases diffusion. The decreased diffusion and solubility of gases consequently promote the improvement of barrier properties for 2,7‐CPAPPI.
An intrinsic high‐barrier polyimide (2,7‐CPAPPI) has been prepared through the polycondensation of pyromellitic dianhydride (PMDA) with a novel diamine (2,7‐CPAPDA), which contains rigid planar carbazole moiety and amide group. With the introduction of carbazole moiety and amide group into the main chain of 2,7‐CPAPPI, the crystallinity increases, and the free volume and chains mobility reduce. Those factors lead to the decrease of gases diffusion and solubility in the PI matrix and consequently improve the barrier properties.
Dominance hierarchy reflects resource competition in male primates as well as females. In this study, we collected data on the social rank and mating competition of female Sichuan snub-nosed monkeys ...from September 2009 to June 2010 in the Qinling Mountains, Shaanxi, China. Displacement was used to determine social hierarchy of the studied wild females. A total of 1223 displacement bouts between adult females and 316 mating behaviors within one-male units （OMUs） were recorded. Competitive displacement among females was very low （0.22 displacements per observation hour）. The dominant ranks of females in target OMUs were determined by displacement, from one OMU to another： JB unit： YL 〉 DBC 〉 YCM 〉XBC 〉 BD; JZT unit： XHW 〉 JG 〉 DT; PK unit： QQ 〉 TM 〉 HF; LP unit： SK 〉 TH 〉 WM. Higher-ranking females performed significantly more sexual behavior than lower-ranking females in this rare monkey. High-ranking females were more likely to win mating contests within those OMUs. Based on these studies, we assessed the social relationships among adult females and clarified possible explanations for the strategies of female mating competition in the OMUs. Furthermore, the notion that reproductive success may also be related to female dominance hierarchies in this polygynous species should be considered in future research.
The comparison analysis of social structures and spatial distributions of golden snub-nosed monkeys(Rhinopithecus roxellana) in different regions is of significance in understanding the mutual ...response among populations and the surrounding environments. This study observes three different groups(Dapingyu troop, Yuhuangmiao troop and Zharugou troop) of golden snub-nosed monkeys in the Qinling Mountains(altitude of 1150-2890 m above sea level) and the Minshan Mountains(altitude of 1996-4764 m above sea level) to compare the differences regarding the social structure and spatial distribution. The results indicate that, due to the different habitat environments, the social structure and spatial distribution show some similarities in common and exists certain differences. All three groups present features of the multi-level system regarding the social structure. The proportion of male and female within One-male unit(OMU) shows significant difference not only among three observe troops, but among other snub-nosed monkeys species as well. For spatial distribution, due to the different effects of food competition and predation pressure on natural enemies in different habitats, the spatial distribution of the three observation groups shows a gradient change relationship. This research facilitates in the current study on Rhinopithecus roxellana regarding its developments and adaptation ability to the environments. Lastly, it is expected that this research could inspire further research and guide conservation works on endangered non-human primates.
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