Development and Application of Fire Video Image Detection Technology in China’s Road Tunnels

A large number of highway tunnels, urban road tunnels and underwater tunnels have been constructed throughout China over the last two decades. With the rapid increase in vehicle traffic, the number of fire incidents in road tunnels have also substantially increased. This paper aims to review the development and application of fire video image detection (VID) technology and their impact on fire safety in China’s road tunnels. The challenges of fire safety in China’s road tunnels are analyzed. The capabilities and limitations of fire detection technologies currently used in China’s road tunnels are discussed. The research and development of fire VID technology in road tunnels, including various detection algorithms, evolution of VID systems and evaluation of their performances in various tunnel tests are reviewed. Some cases involving VID applications in China’s road tunnels are reported. The studies show that the fire VID systems have unique features in providing fire protection and their detection capability and reliability have been enhanced over the decades with the advance in detection algorithms, hardware and integration with other tunnel systems. They have become an important safety system in China’s road tunnels

Bacterial cellulose membrane combined with BMSCs promotes wound healing by activating the notch signaling pathway

ObjectiveThe bacterial cellulose membrane (BCM) has been widely studied and applied as a new biomaterial for wound healing, but causes pain with frequent dressing changes. Local application of bone marrow mesenchymal stem cells (BMSCs) requires a niche. Furthermore, the effect and mechanism of the BCM combined with BMSCs have not been reported.MethodsMorphological and chemical identifications of BCMs were investigated by porosity analyses, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Biological wound dressings (BWDs) were prepared by the BCM in combination with BMSCs. The biological effects of BWDs on human dermal fibroblast (HDF) and VEGF-A in human vascular endothelial cells (HuVECs) were detected in vitro, and the effect of BWDs on acute wounds in mice was detected in vivo. Collagen and angiogenesis were evaluated through hematoxylin–eosin staining and Masson staining. The expressions of COL-1 and VEGF-A and the activation of the Notch signaling pathway in vivo and in vitro were detected by quantitative reverse-transcriptase polymerase chain reaction.ResultsThe BCM had a nanoscale structure and provided a partial niche for the survival and proliferation of BMSCs. BWDs were successfully prepared and regulated the biological behaviors of wound healing-related cells in vitro and upregulated the expressions of COL-1 in HDF and VEGF-A in HuVECs. BWDs promoted wound healing by increasing collagen type I synthesis and angiogenesis in acute wounds in mice.ConclusionsBWDs prepared by the combination of nanomaterial BCMs and BMSCs facilitated acute wound healing, which may be regulated by activating the Notch signaling pathway

Study on Rock Mass Stability Criterion Based on Catastrophe Theory

In rock mass engineering, the criterion of rock mass stability has complex nonlinear characteristics, so the process of instability for local rock mass system cannot be quantified by the traditional ways of displacement criterion and the criterion of development of plastic zones, which are strongly empirical. Based on the research about the criterion of rock mass stability, criterion of improved strain energy catastrophe is put forward by virtue of catastrophe theory in this paper. After regularizing potential function, the stability of the system can be determined by catastrophe characteristic values. Take a certain slope for example; the results show that the criterion can quantitatively reflect the behavioral process of instability for rock mass system, which is consistent with the engineering practice and possesses a certain engineering reference value

Inhibiting function of human fetal dermal mesenchymal stem cells on bioactivities of keloid fibroblasts

Abstract Background Keloid is one kind of benign skin disease caused by hyperplasia of fibroblasts and collagen fibrils. It is refractory due to the lack of an effective treatment at present, which puts pressure on seeking a new therapeutic regimen. Mesenchymal stem cells (MSCs) from fetal skin are considered to play a crucial role in scarless healing. Nevertheless, the efficacy of them in keloid disorders remains poorly understood. Methods Keloid fibroblasts (KFs), human adult dermal fibroblasts (ADFs), and human fetal dermal mesenchymal stem cells (FDMSCs) were isolated to single cells and cultured in Dulbecco’s modified Eagle’s medium (DMEM). ADFs and FDMSCs were used to generate ADF-conditioned medium (A-CM) and FDMSC-conditioned medium (F-CM). The effects of A-CM and F-CM on KFs were tested using MTT assay, BrdU assay, TUNEL assay, quantitative polymerase chain reaction, Western blot, and annexin V-FITC/PI binding assay,. Results FDMSCs inhibited the bioactivity of KFs, downregulated the expression of the antiapoptotic protein BCL-2, and upregulated the expression of the proapoptotic protein BAX of KFs by secreting some soluble substances, thus accelerating the apoptosis of KFs. Conclusion F-CM induces apoptosis of KFs, providing a novel treatment strategy for keloid disorders

Thioesterase domains of fungal nonreducing polyketide synthases act as decision gates during combinatorial biosynthesis

A crucial step during the programmed biosynthesis of fungal polyketide natural products is the release of the final polyketide intermediate from the iterative polyketide synthases (iPKSs), most frequently by a thioesterase (TE) domain. Realization of combinatorial biosynthesis with iPKSs requires TE domains that can accept altered polyketide intermediates generated by hybrid synthase enzymes and successfully release “unnatural products” with the desired structure. Achieving precise control over product release is of paramount importance with O—C bond-forming TE domains capable of macrocyclization, hydrolysis, transesterification and pyrone formation that channel reactive, pluripotent polyketide intermediates to defined structural classes of bioactive secondary metabolites. By exploiting chimeric iPKS enzymes to offer substrates with controlled structural variety to two orthologous O—C bond-forming TE domains in situ, we show that these enzymes act as non-equivalent decision gates, determining context-dependent release mechanisms and overall product flux. Inappropriate choice of a TE could eradicate product formation in an otherwise highly productive chassis. Conversely, a judicious choice of a TE may allow the production of a desired hybrid metabolite. Finally, a serendipitous choice of a TE may reveal the unexpected productivity of some chassis. The ultimate decision gating role of TE domains influences the observable outcome of combinatorial domain swaps, emphasizing that the deduced programming rules are context dependent. These factors may complicate engineering the biosynthesis of a desired “unnatural product”, but may also open additional avenues to create biosynthetic novelty based on fungal nonreduced polyketides

Heat waves reduce ecosystem carbon sink strength in a Eurasian meadow steppe

Background: As a consequence of global change, intensity and frequency of extreme events such as heat waves (HW) have been increasing worldwide. Methods: By using a combination of continuous 60-year meteorological and 6-year tower-based carbon dioxide (CO2) flux measurements, we constructed a clear picture of a HWs effect on the dynamics of carbon, water, and vegetation on the Eurasian Songnen meadow steppe. Results: The number of HWs in the Songnen meadow steppe began increasing since the 1980s and the rate of occurrence has advanced since the 2010s to higher than ever before. HWs can reduce the grassland carbon flux, while net ecosystem carbon exchange (NEE) will regularly fluctuate for 4-5 days during the HW before decreasing. However, ecosystem respiration (Re) and gross ecosystem production (GEP) decline from the beginning of the HW until the end, where Re and GEP will decrease 30% and 50%, respectively. When HWs last five days, water-use efficiency (WUE) will decrease by 26%, soil water content (SWC) by 30% and soil water potential (SWP) will increase by 38%. In addition, the soil temperature will still remain high after the HW although the air temperature will recover to its previous state. Conclusions: HWs, as an extreme weather event, have increased during the last two decades in the Songnen meadow steppe. HWs will reduce the carbon flux of the steppe and will cause a sustained impact. Drought may be the main reason why HWs decrease carbon flux. At the later stages of or after a HW, the ecosystem usually lacks water and the soil becomes so hot and dry that it prevents roots from absorbing enough water to maintain their metabolism. This is the main reason why this grassland carbon exchange decreases during and after HWs. (C) 2015 Elsevier Inc. All rights reserved

Water- and Plant-Mediated Responses of Ecosystem Carbon Fluxes to Warming and Nitrogen Addition on the Songnen Grassland in Northeast China

<div><h3>Background</h3><p>Understanding how grasslands are affected by a long-term increase in temperature is crucial to predict the future impact of global climate change on terrestrial ecosystems. Additionally, it is not clear how the effects of global warming on grassland productivity are going to be altered by increased N deposition and N addition.</p> <h3>Methodology/Principal Findings</h3><p>In-situ canopy CO₂ exchange rates were measured in a meadow steppe subjected to 4-year warming and nitrogen addition treatments. Warming treatment reduced net ecosystem CO₂ exchange (NEE) and increased ecosystem respiration (ER); but had no significant impacts on gross ecosystem productivity (GEP). N addition increased NEE, ER and GEP. However, there were no significant interactions between N addition and warming. The variation of NEE during the four experimental years was correlated with soil water content, particularly during early spring, suggesting that water availability is a primary driver of carbon fluxes in the studied semi-arid grassland.</p> <h3>Conclusion/Significance</h3><p>Ecosystem carbon fluxes in grassland ecosystems are sensitive to warming and N addition. In the studied water-limited grassland, both warming and N addition influence ecosystem carbon fluxes by affecting water availability, which is the primary driver in many arid and semiarid ecosystems. It remains unknown to what extent the long-term N addition would affect the turn-over of soil organic matter and the C sink size of this grassland.</p> </div

Additional file 1: Figure S1. of Inhibiting function of human fetal dermal mesenchymal stem cells on bioactivities of keloid fibroblasts

Direct effect of ADFs and FDMSCs on KFs. ***:P<0.001, ns: no significance. Figure S2. Morphology and characterization of KFs, ADFs, and FDMSCs. Figure S3. Immunofluorescent staining showed that FDMSCs were positive for the mesenchymal stem cell markers CD44, CD90, and CD105. Figure S4. Immunofluorescent staining showed that FDMSCs were negative for the hematopoietic stem cell markers CD14, CD34, and CD45. Figure S5. Flow cytometry showed that FDMSCs were positive for the mesenchymal stem cell markers CD44, CD90, and CD105 (A, B, C) and negative for the hematopoietic stem cell markers CD14, CD34, and CD45 (D, E, F). Figure S6. FDMSCs expressed embryonic markers including SSEA-4 and OCT-4. Figure S7. Immunofluorescent staining showed that KFs, ADFs, and FDMSCs were positive for the dermal cell marker vimentin. Figure S8. Immunofluorescent staining showed that KFs, ADFs, and FDMSCs were negative for the epidermal cell marker CK19. Figure S9. Immunofluorescent staining and BrdU staining showed that F-CM did not alter the nature of KFs. Figure S10. Multilineage differentiation potential of FDMSCs. Alizarin red staining for osteocytes, Oil-red O staining for adipocytes, and Alcian blue staining for Chondrocytes. (DOCX 1210 kb