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Water mist is one of the important substitutes of halon fire extinguishing agents with the advantages of clean and environmental protection. However, there will be a short time of flame intensification in the fire extinguishing progress of water mist, which threatening the safety of surrounding combustibles and fire fighters. The main objective of this study is to assess the suppression performance of N2 twin-fluid water mist containing KQ compound additive (composed of 6% fluorine surfactant and K2CO3) on ethanol pool fire, and analyze the suppressing mechanism on the flame intensification phenomenon. Experimental results showed that: the fire extinguishing time of several fire extinguishing agents from low to high was N2 twin-fluid water mist containing KQ compound additive

Sodium bicarbonate (NaHCO3) was used to suppress the explosion of polyethylene (PE) dust. The maximum explosion pressure, flame propagation behaviour, and the minimum ignition temperature of PE dust mixed with NaHCO3 powder were measured, aiming to evaluate the suppression effect of NaHCO3 on PE dust explosion. The results showed that NaHCO3 powder can effectively suppress PE dust explosions and the suppression effect increases gradually as the inert ratio increases. PE dust explosions can be suppressed by NaHCO3 through physical and chemical mechanisms. From the physical aspect, the thermal decomposition of NaHCO3 particles can effectively absorb heat from the flame front of PE dust. From the chemical aspect, the Na-containing species generated can effectively react with and scavenge the radicals in the PE flame, especially the O radical. Both the rate of chain reaction and the rate of heat release are then decreased, leading to an effective suppression effect.

Oxaliplatin is a first-line clinical drug in cancer treatment and its side effects of peripheral neuropathic pain have also attracted much attention. Neuroinflammation induced by oxidative stress-mediated activation of nuclear factor-kappa B (NF-κB) plays an important role in the course. Current studies have shown that curcumin has various biological activities like antioxidant, anti-inflammatory, antitumor and so on, while few studies were conducted about its role in oxaliplatin-induced peripheral neuropathic pain. The aim of this study is to verify the mechanism of curcumin alleviating oxaliplatin-induced peripheral neuropathic pain. Intraperitoneal injection with oxaliplatin (4 mg/kg body weight) was given to the rats twice a week and last for four weeks to establish the model rats. Gavage administration of curcumin (12.5, 25, and 50 mg/kg body weight, respectively) was conducted for consecutive 28 d to explore the effects and potential mechanism. Our results showed that curcumin administration could increase mechanical withdrawal threshold and decrease the paw-withdrawal times of cold allodynia significantly; meanwhile, motor nerve conduction velocity (MNCV) and sense nerve conduction velocity (SNCV) were both increased and the injured neurons of the spinal cord were repaired. In addition, curcumin administration increased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and reduced malondialdehyde (MDA). Moreover, the curcumin operation inhibited the activated of NF-κB and level of inflammatory factors like tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). In conclusion, these findings suggested that curcumin could alleviate oxaliplatin-induced peripheral neuropathic pain; the mechanism might be inhibiting oxidative stress-mediated activation of NF-κB and mitigating neuroinflammation.

The inhibition and control of combustible gas explosions is an issue of interest in the field of industrial and public safety. Based on a self-built twin-fluid water mist explosion suppression system in pipeline, this paper carried out a series of methane/air explosion inhibition experimental studies by N2-twin-fluid water mist containing sodium chloride additive. The results showed that N2-twin-fluid water mist containing sodium chloride additive could obtain an better inhibition effect on methane/air explosions. The reason was that: N2-twin-fluid water mist containing sodium chloride additive enhanced the synergistic effects of physical and chemical inhibition. With the preferential diffusion and thermal effects of nitrogen, the flame speed was reduced, which prolonged the residence time of droplets in the flame zone and enhanced the cooling effect of the water mist; moreover, this prolonged the residence time of sodium chloride additive in the flame zone; therefore enhanced the heterogeneous chemistry and homogeneous chemistry inhibition effects on methane/air explosion.

An experiment of inhibition effects by porous media and ultra-fine water mist on stoichiometric methane/air (9.5% methane) explosion was investigated in a semi-confined transparent explosion vessel...

Cellular instability is responsible for the self-acceleration of a flame, and such acceleration might cause considerable damage. This paper presents an experimental study on the inhibition effect of CO2 and an ultrafine water mist on the self-acceleration characteristics of a spherical flame in the initial stage of a 9.5% methane/air explosion in a constant volume combustion bomb. Results showed that insufficient water mist enhanced the self-acceleration of the spherical flame and the intensity of the explosion; nevertheless, the synergistic inhibition effect of CO2 and ultrafine water mist prevented enhancement of the explosion and significantly mitigated the self-acceleration of spherical flames, which observably delayed the appearance time of a cellular flame, and reduced the flame propagation speed, overpressure and the mean rate of pressure rise, indicating that suppression of flame self-acceleration could effectively mitigate the damage from a methane/air explosion. The reason for the synergistic effect was a result of a combination of physical suppression and chemical suppression: due to the preferential diffusion dilution effect of CO2, the initial flame speed was reduced, and the flame became thicker, which increased the evaporation time and quantity of droplets around the flame front, accordingly enhancing the cooling effect on the flame front. The increased flame thickness could withstand greater disturbance and inhibit the formation and development of a cellular flame. Meanwhile, CO2 and H2O can also reduce the concentration of active radicals (O, H and OH) and reduce the reaction rate and combustion rate of a methane/air explosion.

Porous materials offer an attractive pathway to enhance the nanofiltration performance of thin film nanocomposite (TFN) membranes. Widely studied porous materials, such as zeolite, and metal–organic frameworks suffer from interfacial defects and poor dispersion in a polymer matrix, which leads to less than optimal performance of the TFN membranes. Porous metal–organic molecular cages are an exciting new family of porous materials that could ameliorate these issues by their better dispersing ability and intimate integration within the polymer matrix. By using the interfacial polymerization (IP) process, we synthesized a novel polyamide (PA) TFN membrane with highly improved nanofiltration performance using porous iron–organic molecular cage (Fe-cage) as the filler. Owing to the porous tetrahedral structure and polar –SO3Na group of the Fe-cage, the as-synthesized PA/Fe-cage TFN membranes at 1.0 wt% Fe-cage concentration in the aqueous solution showed water flux up to 26.33 L m−2 h−1, which was 3 times more than that of neat PA thin film composite (TFC) membranes, while simultaneously increasing the rejection ratio to 89.3% for Na2SO4 and 96% for Congo red. Further, the addition of Fe-cages induced a significant improvement in the antifouling property of the membranes, which could be attributed to both increased hydrophilicity and smooth surface microstructure of the membranes. These results provide a starting point for the high-performance TFN NF membranes by utilizing porous metal–organic molecular cages.

Premixed hydrogen/air deflagrations were performed in a 100 mm × 100 mm × 1000 mm square duct closed at one end and opened at the opposite end under ambient conditions, concerning with the combined effect of ignition position IP and equivalence ratio ∅. A wide range of ∅ ranging from 0.4 to 5.0, as well as multiple IPs varying from 0 mm to 900 mm off the closed end of the duct were employed. It is indicated that IP and ∅ exerted a great impact on the flame structure, and the corresponding pressure built-up. Except for IP0, the flame can propagate in two directions, i.e., leftward and rightward. A regime diagram for tulip flames formation on the left flame front (LFF) was given in a plane of ∅ vs. IP. In certain cases (e.g. the combinations of ∅ = 0.6 and IP500 or IP700), distorted tulip flames were also observed on the right flame front (RFF). Furthermore, the combinations of IP and ∅ gave rise to various patterns of pressure profiles. The pressure profiles for ignition initiated at the right half part of the duct showed a weak dependence on equivalence ratio, and showed no dependence on ignition position. However, the pressure profiles for ignition initiated at the left half part of the duct were heavily dependent on the combination of IP and ∅. More specifically, in the leanest (∅ = 0.4) and the richest (∅ = 4.0–5.0) cases, intensive periodical oscillations were the prime feature of the pressure profiles. With the moderate equivalence ratios (∅ = 0.8–3.0), periodical pressure oscillations were only observed for IP900. The maximum pressure peaks Pmax were reached at ∅ = 1.25 rather than at the highest reactivity ∅ = 1.75 irrespective of ignition position. The ignition positions that produced the worst conditions were different, implying a complex influence of the combination of IP and ∅.

At present, there have been large numbers of methane transport pipelines in coal mine in china. Explosion accident is most likely to be triggered if affected by leakage or external fire. In order to improve the suppression effect of single fluid water spray technology, this paper studied the suppression performance of two fluid water mist system on methane/air explosion. A transparent organic glass pipeline was designed for gas explosion, with the dimensions of 0.84 × 0.12 × 0.12 m. A two fluid nozzle was used to suppress methane/air explosion. Then testing was performed on the explosion suppression properties of two fluid water mist system by adjusting the spray time and N2 and CO2 pressure. The explosion suppression effect of the inert gas two fluid water mist was examined by analyzing the methane explosion overpressure and flame propagation speed. The experimental results showed that: when using N2 or CO2 for the driving force, the explosion suppression effect of the inert gas two fluid water mist was significant, and the peak explosion overpressure, average rise rate of pressure rise and peak speed value of the explosion flame were all gradually decreased by extending the spray time. Such as when the spray time was 3 s and the CO2 pressure was 0.4 MPa, the average velocity of the flame decreased by 81.32%, peak explosion overpressure decreased by 51.44%, and average pressure rise rate decreased by 72%.

In this work, the new laminar flame speeds of hydrogen/dimethyl-ether/methane/air mixtures (H2/DME/CH4) covering wide ranges of equivalence ratios (0.6–1.6) and hydrogen enrichment ratios (0%–100%) were measured using spherical expansion flame method. Four DME chemical reaction kinetic mechanisms (Zhao mechanism, Wang mechanism, Sandiego mechanism and Chen mechanism) were used to calculate the laminar flame speeds and compared with the experimental measured data. Results showed that the experimental data agreed well with the calculated values using Zhao mechanism. The laminar flame speeds were observed to increase significantly with hydrogen enrichment ratio and they can be divided into three stages depending on the hydrogen enrichment ratio in the H2/DME/CH4 fuel. Furthermore, the laminar flame speeds at fuel-rich conditions were more sensitive to hydrogen enrichment than fuel-lean conditions. In the increasing hydrogen atmosphere, the diffusional-thermal instability was enhanced for fuel-lean conditions, while it was effectively suppressed for fuel-rich conditions. The hydrodynamic instability was enhanced for all cases, which was mainly due to the decrease of flame thickness. Numerical simulation revealed that with the enrichment of hydrogen, the laminar flame speeds have the strongest correlation with H + O radicals for the fuel-lean and fuel-rich conditions, while H radicals have the strongest correlation for the stoichiometric condition. Furthermore, the adiabatic flame temperature and thermal diffusivity can be enhanced with the enrichment of hydrogen.

In this study an experiment system was built to explore the suppression of methane/air explosion in pipe via water mist. And droplet size of water mist and pipe size were investigated to shed light on their influence on explosion. It was found that for water mist droplet diameter of 45 μm and 100 μm it was impossible to suppress the explosion. Instead it promoted the explosion and the larger the diameter, the more easily the gas exploded. But it was effective to suppress the explosion with the presence of fine water mist with droplet more than 160 μm in diameter and the larger the ratio of the pipe length to its diameter, the better its effectiveness in decreasing flame propagation velocity and suppressing gas explosion. This study can provides theoretical foundation for the designing of water mist explosion suppression system in different industry occasions.

Experiments of synergistic inhibition effects by N2 or CO2, and ultrafine water mist on methane/air explosion were carried out in a semi-confined transparent explosion vessel. The maximum flame propagation speed, maximum temperature, and maximum overpressure were found to be significantly decreased in the presence of a lower amount of gas-liquid two phase medium. It was also found that the CO2 had a better synergistic inhibiting effect with the ultrafine water mist than the N2. In the present study, 14% N2 or CO2 and 2 min mist spraying time were necessary to achieve better inhibition effects, such as declines of the maximum overpressure were 69.8% and 74.4%; and the declines of the maximum temperature were 43.4% and 51.9%; and the maximum flame propagation speed was between 2.13 m.s−1 and 3.6 m.s−1, respectively. The experimental results obtained from the present study could potentially facilitate the designs of explosion suppression engineering using water mist inerting systems.

Based on the self-designed sliding porous media system, the suppression effect of sliding porous devices with different elastic coefficients and different pore diameter on the propagation characteristics of premixed methane/air explosions with φ = 1 was investigated. The results show that the sliding porous media has a significant inhibition effect on the explosion flame and overpressure, which can reduce the propagation speed and duration of the flame and the maximum value of the downstream overpressure. The advantage of sliding porous media is to increase the contact time and distance between the device and the flame and shock wave produced by explosion, so as to increase the explosion energy consumption and achieve the purpose of explosion suppression.

In order to study the influences of coal dust components on the explosibility of hybrid mixture of methane and coal dust, four kinds of coal dust with different components were selected in this study. Using the standard 20 L sphere, the maximum explosion pressure, explosion index and lower explosion limits of methane/coal dust mixtures were measured. The results show that the addition of methane to different kinds of coal dust can all clearly increase their maximum explosion pressure and explosion index and decrease their minimum explosion concentration. However, the increase in the maximum explosion pressure and explosion index is more significant for coal dust with lower volatile content, while the decrease in the minimum explosion concentration is more significant for coal dust with higher volatile content. It is concluded that the influence of methane on the explosion severity is more pronounced for coal dust with lower volatile content, but on ignition sensitivity it is more pronounced for coal dust with higher volatile content. Bartknecht model for predicting the lower explosion limits of methane/coal dust mixture has better applicability than Le Chatelier model and Jiang model. Especially, it is more suitable for hybrid mixtures of methane and high volatile coal dust.

In recent years, Chinese medicine has played an important role in the prognosis of gastric cancer. Precancerous lesions of gastric carcinoma (PLGC) is a class of gastric cancer which is closely related to the gastric mucosal pathology changes in the role of carcinogenic incentives, and plays key role in the progression of normal gastric mucosal cells into gastric cancerous cells. In current experiment, we explore the relationship between Chinese traditional medicine (Xiao Tan He Wei Decoction) and gastric cancer in the PLGC rat animal models and epithelial-mesenchymal transitioned GES-1 cells which were induced useing 1- Methyl-3-nitro-1-nitrosoguanidine (MNNG). PLGC rat model showed significant deterioration in the gastric mucosa with terrible growth rate in body weight and more atypical hyperplasia in gastric mucosa. MC cells, MNNG induced GES-1 cells which epithelial- mesenchymal-transition (EMT)-related proteins have a great change compare with normal GES-1 cells. The cells had characteristics of malignant cells including proliferation, invasion and metastasis ability. Our research founds that Xiao Tan He Wei Decoction could inhibit cell proliferation and increased apoptosis by increase the level of pro-apoptotic proteins like Bax and caspase-3 and decreased the level of anti-apoptotic protein Bcl-2, block the cells in G0/G1 phase simultaneously. Furthermore, Xiao Tan He Wei Decoction could inhibit nuclear factor kappa-light-chain-enhancer (NF-kB) activity and inhibit its transfer from the cytoplasm to the nucleus. However, when we incubated with NF-κB activator PMA, the effect of Xiao Tan He Wei Decoction was reversed. These results suggested that Xiao Tan He Wei Decoction could be used as a method for the treatment of gastric precancerous lesions, and possibly provide a theoretical basis for the clinical treatment of gastric cancer and gastric precancerous lesions.

In this study, in order to research the synergistic inhibition effect of nitrogen and ultrafine water mist on gas explosion in a vented duct, a semi-confined transparent chamber was designed with the size of 120 × 120 × 840 mm, and the experiments were carried out with stoichiometric methane/air premixed mixture (fraction of methane: 9.5%), adding different fractions of nitrogen and ultrafine water mist. The experimental results showed the following: The combination of nitrogen and ultrafine water mist had a synergistic inhibiting effect on methane/air explosion, which was preferable to the single use of any kind. With the increase of spraying time of water mist and fraction of nitrogen, the initial shape of the explosion flame became snakelike, and at the same time the peak flame propagation speed and peak overpressure decreased significantly. When the nitrogen fraction was increased to 10% and the mist spraying time was increased to 2min, synergistic inhibiting effect on overpressure was high efficient. However, with the increase of spraying time of water mist and fraction of nitrogen going on, the amount of increase of explosion inhibition efficiency was gradually reduced.

La-B-TiO2photocatalysts were prepared using tetrabutyl titanate, tributyl borate, and lanthanum chloride as the precursors by solvothermal method. The prepared sample is composed of irregular particles with fairly rough surface in the size within 5 μm. Large surface area and pore volume are benefit to adsorption and photocatalytic degradation activity of the materials. Pore size of the 1%La-3%B-TiO2sample mainly distributes in the range between 5-35 nm. Specific surface area of the material is 101.45 m2/g. The sample containing 0.5% La presents the maximum decoloration efficiency. When La content is 0.5%, methyl orange adsorption rate on the material is less than 5%, and photocatalytic degradation rate is 39.9%.

In order to study the inhibition effect of gas⁻solid two-phase inhibitors on a methane explosion, the influence of these parameters was investigated and compared with that of single-phase inhibitors. The results show that the inhibition effect of gas⁻solid two-phase inhibitors on a methane explosion is better than the added effect of two single-phase inhibitors, indicating that a synergistic effect can be obtained by gas⁻solid two-phase inhibitors. The two-phase inhibitors which are composed of NaHCO3 (BC) powders and inert gas have a better suppressing property than those composed of NH4H2PO4 (ABC) powders and inert gas. The two-phase inhibitors composed of CO2 and powders have a better suppressing property than those composed of N2 and powders. The 9.5% premixed methane⁻air mixture can be completely inhibited by 0.10 g/L BC powders mixed with 8% CO2. The suppression mechanisms of the gas⁻solid two-phase inhibitors on the methane explosion were discussed.

Radiation-induced bystander effects (RIBE) have been demonstrated to occur widely in various cell lines. However, very little data is available on the genotoxic effects of RIBE combined with other factor(s). We reported previously that with a low dose of alpha-particle irradiation, the fraction of gamma-H2AX foci-positive cells in non-irradiated bystander cells was significantly increased under elevated NaCl culture conditions. In this study, we further investigated the functional role of NaCl in the enhancement of RIBE using a specially designed co-culture system and micronucleus (MN) test. It was shown that the MN frequency was not increased significantly by elevated NaCl (9.0 g/L) alone or by medium exposure. However, with 1.0 cGy alpha-particle irradiation, the induced MN frequency increased significantly in both irradiated and non-irradiated bystander regions. Additional studies showed that elevated NaCl made the non-irradiated bystander cells more vulnerable to bystander factors. Furthermore, it was found that the induced MN frequency in cells both in irradiated and non-irradiated bystander regions was weakened when the hypertonic medium was changed to normotonic medium for 2h before irradiation. Such observations were quite similar to the co-effect of NaCl and hydrogen peroxide (H(2)O(2)), indicating that elevated NaCl might sensitize non-irradiated cells to bystander factors-induced oxidative stress.

Many studies have shown that arsenite is a potent inducer of apoptosis both in cells and tissues. However, there is a lack of appropriate in vivo animal models to study the underlying mechanisms of arsenite-induced apoptosis. Caenorhabditis elegans is an excellent model organism for studying many biological processes. We showed previously that C. elegans could be used as an in vivo system to investigate the genotoxic effects of arsenite. In order to elucidate the underlying mechanisms of arsenite-induced apoptosis in vivo, in the present study, we used the mutated alleles of the C. elegans homologue of known mammalian genes that are involved in the regulation of apoptosis. Our results showed that the loss-of-function mutations of p53/ cep-1 and DNA damage response (DDR) genes hus-1, clk-2, and egl-1 exhibited significant increase in germline apoptosis under arsenite exposure, whereas arsenite-induced germline apoptosis was blocked in loss-of-function alleles of extracellular signal-regulated kinase (ERK) (lin-45 (ku51), mek-2 (n1989), and mpk-1 (ku1)), c-Jun N-terminal kinase (JNK) (jkk-1 (km2), mek-1 (ks54), jnk-1 (gk7), mkk-4 (ju91)), and p38 ( nsy-1 (ag3), sek-1 (ag1), and pmk-1 (km25)) MAPK cascades. These results suggest that arsenite-induced apoptosis occurs independently of p53/ cep-1 and the DNA damage response (DDR) genes hus-1, clk-2, and egl-1 and that the C. elegans caspase gene ced-3, Apaf-1 homologue ced-4, and the MAPK signaling pathways are essential for germline apoptosis. Moreover, our study demonstrates that C. elegans could be a mammalian in vivo substitute model to study the mechanisms of apoptosis.

International audience; The shelterin proteins protect telomeres against activation of the DNA damage checkpoints and recombinational repair. We show here that a dimer of the shelterin subunit TRF2 wraps ∼ 90 bp of DNA through several lysine and arginine residues localized around its homodimerization domain. The expression of a wrapping-deficient TRF2 mutant, named Top-less, alters telomeric DNA topology, decreases the number of terminal loops (t-loops), and triggers the ATM checkpoint, while still protecting telomeres against non-homologous end joining (NHEJ). In Top-less cells, the protection against NHEJ is alleviated if the expression of the TRF2-interacting protein RAP1 is reduced. We conclude that a distinctive topological state of telomeric DNA, controlled by the TRF2-dependent DNA wrapping and linked to t-loop formation, inhibits both ATM activation and NHEJ. The presence of RAP1 at telomeres appears as a backup mechanism to prevent NHEJ when topology-mediated telomere protection is impaired.

A major issue in telomere research is to understand how the integrity of chromosome ends is controlled. The fact that different types of nucleoprotein complexes have been described at the telomeres of different organisms raises the question of whether they have in common a structural identity that explains their role in chromosome protection. We will review here how telomeric nucleoprotein complexes are structured, comparing different organisms and trying to link these structures to telomere biology. It emerges that telomeres are formed by a complex and specific network of interactions between DNA, RNA, and proteins. The fact that these interactions and associated activities are reinforcing each other might help to guarantee the robustness of telomeric functions across the cell cycle and in the event of cellular perturbations. We will also discuss the recent notion that telomeres have evolved specific systems to overcome the DNA topological stress generated during their replication and transcription. This will lead to revisit the way we envisage the functioning of telomeric complexes since the regulation of topology is central to DNA stability, replication, recombination, and transcription as well as to chromosome higher-order organization.

TRF1 and TRF2 are key proteins in human telomeres, which, despite their similarities, have different behaviors upon DNA binding. Previous work has shown that unlike TRF1, TRF2 condenses telomeric, thus creating consequential negative torsion on the adjacent DNA, a property that is thought to lead to the stimulation of single-strand invasion and was proposed to favor telomeric DNA looping. In this report, we show that these activities, originating from the central TRFH domain of TRF2, are also displayed by the TRFH domain of TRF1 but are repressed in the full-length protein by the presence of an acidic domain at the N-terminus. Strikingly, a similar repression is observed on TRF2 through the binding of a TERRA-like RNA molecule to the N-terminus of TRF2. Phylogenetic and biochemical studies suggest that the N-terminal domains of TRF proteins originate from a gradual extension of the coding sequences of a duplicated ancestral gene with a consequential progressive alteration of the biochemical properties of these proteins. Overall, these data suggest that the N-termini of TRF1 and TRF2 have evolved to finely regulate their ability to condense DNA.