Fire Research Articles

Post-Fire Changes in Canopy Solute Leaching in Pinus densiflora Forests

Fires can burn canopy fuel and replace leafy crowns with charred branches and trunks, thereby affecting hydrological flow and water chemistry. However, little is known about the effects of fire on throughfall volumes and chemical fluxes in temperate forests. Therefore, we aimed to monitor the volume and chemistry of throughfall in pine trees (Pinus densiflora) damaged by the 2022 Gangneung-Donghae Forest fire in the Republic of Korea. Immediately after the forest fire, funnel-type measurements were performed to collect the throughfall beneath five trees at foliage necrosis and crown consumption sites. The amount of water that penetrated in a specified period was continually measured and analyzed in terms of the water quality components. Crown consumption resulted in the passage of more water due to the removal of the tree canopy; however, the ratio of throughfall to total rainfall remained constant as the rainfall amount increased. The throughfall volume was not significantly different owing to the fire damage. The solute concentrations of Ca and TOC at the crown consumption site were higher than those at the foliage necrosis site after the fire; however, no significant difference was observed three months after the fire. In this study, the changes in the amount and water quality of throughfall due to fire were examined over a relatively short period, providing fundamental data for nutrient cycling management of wildfire-damaged soil.

Effect of Solution Heat-Treatment on the Oxidation Resistance of Ni-Base Single-Crystal Superalloy

To clarify the effect of solution heat-treatment on the oxidation resistance of Ni-base single-crystal superalloy TMS-238, the evaluation of dendrite/inter-dendrite segregation of alloying elements in the as-cast and heat-treated samples, and its effect on cyclic oxidation resistance were investigated. Cyclic oxidation test results at 1100 °C for up to 150 cycles clearly showed that the as-cast samples with element segregations had lower oxidation resistance compared to heat-treated samples with homogeneous structure. Further, for the as-cast sample, rapid growth and spallation of oxide consisting of NiO, Cr2O3, and Al2O3 were observed around the dendrite core for 10 cycles of oxidation. Analysis of sub-surface on sample isothermally oxidized at 1100 °C for 10 minutes showed that rapid oxide growth is due to the formation of discontinuous Al2O3 layer at dendrite core with lower Al concentration. Furthermore, in this study, the threshold value of Al concentration and Gibbs energy for the formation of continuous Al2O3 layer were estimated and determined to be around 5.2 wt pct and − 556.6 ± 0.5 kJ/mol, respectively. This indicated that the solution heat-treatment for TMS-238 should be conducted above 1305 °C for exhibiting oxidation resistance at 1100 °C, to meet the threshold value within the whole region between dendrite and inter-dendrite.

Forestry ecological security measurements and obstacle factor analysis in Yunnan

Forestry ecological security is not only a necessary condition for sustainable development of forestry economy, but also an important guarantee for protecting biodiversity and reducing carbon emissions. It plays a crucial role in achieving high-quality industrial development and ecological civilization construction goals. The ecological security of forestry in Yunnan was examined from 2011 to 2020 using the PSR model, entropy power technique, and barrier degree model. The results show that the forestry ecological safety composite index generally shows an improving trend, rising from 0.3495 in 2011 to 0.7290 in 2020. The index of forestry industry pressure subsystem and human response subsystem has an increasing trend, with an average annual increase of 22.36% and 34.05%, respectively. The index of forest ecological subsystem is on a decreasing trend. Urban sewage discharge intensity, forestry investment, per capita GDP, per capita water resources, per capita forest area, and per capita forest fire damage area were the main obstacle factors impacting forestry ecological security in Yunnan.

Fire in Hansŏng: Conflagrations and Arson in Fifteenth-Century Korea

The use of fire and its associated risks are universal across all cultures. In pre-industrial times, it was common for people to use open flames daily. Nonetheless, while fire brought many valuable aspects to their everyday lives, it could quickly get out of control and become a significant threat to human settlements and lives. The capital city of Chosŏn Kingdom 朝鮮 (1392–1897), Hansŏng 漢城, was no exception when it came to its susceptibility to conflagrations. Regardless of their origin, repeated fire incidents played a significant role in the formative processes of the city. While many English-language publications have been written on the fire history of various countries, the history of fire prevention and protection in pre-indus- trial Korea remains relatively unexplored and unknown to anglophone audiences. This paper aims to shed light on this lesser-known aspect of Korean history by addressing the topic of urban fires and arson in fifteenth-century Chosŏn, focusing on the capital city area and its struggles with anthropogenic fires. By examining some of the extant early Chosŏn administrative records, the paper explores how the administration of the capital city reacted to and coped with repeated incidences of fire. The paper shows that religious and practical approaches toward fire disasters coexisted alongside each other without being mutually exclusive, and introduces two major conflagrations that significantly influenced government policy towards fire incidents—the great fire of Hansŏng in 1426 and the Ch’angdŏk palace fire in 1467.

X-ray diagnostics of fire damage vessels of the abdominal cavity of the retroperitoneal space

This article deals with the analysis of damage to the main vessels of the abdominal cavity. In particular, the article is devoted to the radiological diagnosis of damage to the vessels of the abdominal cavity caused by gunshot wounds. The article examines various methods and technologies of using X-ray and computer tomographic imaging for accurate localization and characterization of damage to the vascular bed. The author of the article emphasizes the importance of the clinical significance of such a diagnosis, its advantages, and possible limitations in its use for effective treatment of victims. A detailed review of foreign research was conducted to adapt and study the existing world experience in the direction of research for the opportunity to provide timely and high-quality assistance to victims.
 The aim. The aim of the work is the theoretical substantiation of gunshot injuries to the main vessels of the abdominal cavity of the retroperitoneal space.
 Scientific novelty. For the first time, a detailed analysis of damage to the main vessels of the abdominal cavity of the retroperitoneal space was carried out.
 Materials and methods. Analysis of theoretical sources, comparison, induction of isolated analytical data. The research was conducted on the basis of the repository of scientific texts of the State Institution "Amosov National Institute of Cardiovascular Surgery of the National Academy of Medical Sciences of Ukraine".
 Results. It was determined that with the help of MSCT-angiography, signs of damage to the main vessels of the abdominal cavity can be accurately diagnosed, additional information about damage to bone structures, neighbouring organs and tissues is obtained.
 Conclusions. It was determined that MSCT-angiography has become the main method of assessing gunshot injuries to the vessels of the abdominal cavity. Using this method allows you to accurately determine the location and nature of injuries, which helps doctors in choosing the optimal treatment plan for affected patients. However, it is important to consider the possible limitations of this method and to develop additional diagnostic strategies for a complete and comprehensive assessment of vascular injuries

Postfire performance of pultruded wood-cored GFRP sandwich beams

Wood-cored sandwich components have been extensively used in constructions of buildings and bridges. However, the existing studies on the postfire behavior of these components are very limited. This study aims to quantitatively evaluate the postfire residual properties of the pultruded wood-cored GFRP sandwich (PWGS) beams. This paper mainly comprises three parts: (i) review of fire experiment of the PWGS beams; (ii) postfire bending experiments conducted on the PWGS beams with different fire scenarios and (iii) numerical study on thermal and postfire thermomechanical responses. It was found the failure modes mainly depended on the number of exposed sides and the fire damage degree. For the three-sided fire-exposed specimens (except for the one with a 25 mm-thick calcium silica board), the progressive tension rapture of the charred fibers was the dominant failure mode. The other specimens, however, exhibited the brittle in-plane shear failure of the web. Moreover, after cooling down from 250 °C to 20 °C, the GFRP and wood exhibited 68 % and 35 % of recoveries of elastic modulus respectively. A three-dimensional thermal model with kinetic thermophysical sub-models considering heat transfer, water evaporation and decomposition was developed. The developed thermal model accurately predicted the temperature responses and charring profiles. Furthermore, a thermomechanical model considering the material damage was developed to accurately predict the elastic modulus distribution, postfire residual bending capacity and failure modes. This study provides the basis for the retrofit and the reinforcement of the fire-damaged PWGS beams. In the future, study on the fire resistance of the PWGS components in fire will be required.

Comparative studies on oxidation behaviour of cobalt-based D-gun coatings on boiler steel

The protection system against material degradation at elevated temperatures is gaining technological importance. Three cobalt-based coatings were developed on SAE213-T91 boiler steel using the detonation gun method. The oxidation performance of all the specimens was examined for 50 cycles of 1 h heating at 900 °C in a thermal cyclic furnace and 20 min cooling at 25 °C outside the furnace. All the oxidised samples were investigated through SEM/X-ray mapping and an X-ray diffraction analyser. All the specimens obeyed the parabolic rate law of oxidation approximately. The oxidation resistance of Stellite 6 coating was found to be superior among all coated and uncoated specimens due to the growth of protective oxide Cr2O3 and CoCr2O4 spinel in it. The development of Ni, Cr and Co oxides in Stellite 21 coating resulted into its slow oxidation rate, whereas the growth of the non-protective WO3 and CoWO4 phases in WC-Co coating caused its rapid oxidation.

Shock-induced atomisation of a liquid metal droplet

The present study uses Galinstan as a test fluid to investigate the shock-induced atomisation of a liquid metal droplet in a high-Weber-number regime $(We \sim 400\unicode{x2013}8000)$ . Atomisation dynamics is examined for three test environments: oxidizing (Galinstan–air), inert (Galinstan–nitrogen) and conventional fluids (deionised water–air). Due to the readily oxidizing nature of liquid metals, their atomisation in an industrial scale system is generally carried out in inert atmosphere conditions. However, no previous study has considered gas-induced secondary atomisation of liquid metals in inert conditions. Due to experimental challenges associated with molten metals, laboratory scale models are generally tested for conventional fluids like deionised water, liquid fuels, etc. The translation of results obtained from conventional fluid to liquid metal atomisation is rarely explored. Here a direct multiscale spatial and temporal comparison is provided between the atomisation dynamics of conventional fluid and liquid metals under oxidizing and inert conditions. The liquid metal droplet undergoes breakup through the shear-induced entrainment mode for the studied range of Weber number values. The prevailing mechanism is explained based on the relative dominance of droplet deformation and Kelvin–Helmholtz wave formation. The study provides quantitative and qualitative similarities for the three test cases and explains the differences in morphology of fragmenting secondary droplets in the oxidizing test case (Galinstan–air) due to rapid oxidation of the fragmenting ligaments. A phenomenological framework is postulated for predicting the morphology of secondary droplets. The formation of flake-like secondary droplets in the Galinstan air test case is based on the oxidation rate of liquid metals and the properties of the oxide layer formed on the atomizing ligament surface.

Masonry walls strengthened with Textile Reinforced Mortars (TRM) and subjected to in-plane cyclic loads after real fire exposure

A key feature that determines the seismic performance of masonry buildings is the ability of the walls to withstand in-plane cyclic loads. In this context, Textile Reinforced Mortars (TRM) have proven to be a very suitable strengthening solution, although their effectiveness after high temperature exposure is currently practically unexplored. This paper proposes an experimental campaign with full-scale brick walls and carbon fiber TRM, tested to failure under horizontal cyclic in-plane loads, after being exposed to temperatures of about 1000 °C by exposure to real fire. TRM is applied on one or both sides of the walls, and after or before exposure to fire, to simulate different scenarios that a real building could be exposed to. The results show that high temperatures can seriously compromise the integrity of the walls, while TRM can provide effective protection and prevent cracking of masonry from fire. Even after previous fire damage, the reinforcements can double the shear strength of unreinforced damaged walls, and provide high ductility and energy dissipation capacity. However, it is important to note that TRM, even undamaged, may not be able to properly retrofit a severely fire-damaged wall.

A regional modelling study of halogen chemistry within a volcanic plume of Mt Etna's Christmas 2018 eruption

Abstract. Volcanoes are known to be important emitters of atmospheric gases and aerosols, which for certain volcanoes can include halogen gases and in particular HBr. HBr emitted in this way can undergo rapid atmospheric oxidation chemistry (known as the bromine explosion) within the volcanic emission plume, leading to the production of bromine oxide (BrO) and ozone depletion. In this work, we present the results of a modelling study of a volcanic eruption from Mt Etna that occurred around Christmas 2018 and lasted 6 d. The aims of this study are to demonstrate and evaluate the ability of the regional 3D chemistry transport model Modèle de Chimie Atmosphérique de Grande Echelle (MOCAGE) to simulate the volcanic halogen chemistry in this case study, to analyse the variability of the chemical processes during the plume transport, and to quantify its impact on the composition of the troposphere at a regional scale over the Mediterranean basin. The comparison of the tropospheric SO2 and BrO columns from 25 to 30 December 2018 from the MOCAGE simulation with the columns derived from the TROPOspheric Monitoring Instrument (TROPOMI) satellite measurements shows a very good agreement for the transport of the plume and a good consistency for the concentrations if considering the uncertainties in the flux estimates and the TROPOMI columns. The analysis of the bromine species' partitioning and of the associated chemical reaction rates provides a detailed picture of the simulated bromine chemistry throughout the diurnal cycle and at different stages of the volcanic plume's evolution. The partitioning of the bromine species is modulated by the time evolution of the emissions during the 6 d of the eruption; by the meteorological conditions; and by the distance of the plume from the vent, which is equivalent to the time since the emission. As the plume travels further from the vent, the halogen source gas HBr becomes depleted, BrO production in the plume becomes less efficient, and ozone depletion (proceeding via the Br+O3 reaction followed by the BrO self-reaction) decreases. The depletion of HBr relative to the other prevalent hydracid HCl leads to a shift in the relative concentrations of the Br− and Cl− ions, which in turn leads to reduced production of Br2 relative to BrCl. The MOCAGE simulations show a regional impact of the volcanic eruption on the oxidants OH and O3 with a reduced burden of both gases that is caused by the chemistry in the volcanic plume. This reduction in atmospheric oxidation capacity results in a reduced CH4 burden. Finally, sensitivity tests on the composition of the emissions carried out in this work show that the production of BrO is higher when the volcanic emissions of sulfate aerosols are increased but occurs very slowly when no sulfate and Br radicals are assumed to be in the emissions. Both sensitivity tests highlight a significant impact on the oxidants in the troposphere at the regional scale of these assumptions. All the results of this modelling study, in particular the rapid formation of BrO, which leads to a significant loss of tropospheric ozone, are consistent with previous studies carried out on the modelling of volcanic halogens.

Innovating fire safety with recombinant hydrophobic proteins for textile fire retardancy.

Fire retardancy for textiles is important to prevent the rapid spread of fire and minimize damage to property and harm to human life. To infer fire-resistance on textile materials such as cotton or nylon, chemical coatings are often used. These chemicals are usually toxic, and economically and environmentally unsustainable, however, some naturally produced protein-based fire retardants could be an alternative. A biofilm protein from Bacillus subtilis (BslA) was identified and recombinantly expressed in Escherichia coli with a double cellulose binding domain. It was then applied to a range of natural and synthetic fabric materials. A flame retardancy test found that use of BslA reduced fire damage by up to 51% and would pass fire retardancy testing according to British standards. It is therefore a viable and sustainable alternative to current industrial fire-retardant coatings.

Facile microwave synthesis of multi‐walled carbon nanotubes for modification of elastomer used as heaters

AbstractMulti‐walled carbon nanotubes (MWCNTs) were synthesized by a microwave method. MWCNTs had filamentous shapes (10 μm) and were intertwined in bundles (40–60 nm diameter). The rapid oxidation of MWCNTs with a loss of 90% of weight was observed from 530 to 630°C. 2% Residue was present at 630°C, which gradually decreased to 1.2% at 1000°C. In a silicone elastomer, increased thermal conductivity at a concentration of 8% MWCNTs was observed. The highest thermal conductivity of the nano‐modified elastomer was 0.48 W/m°C with 8.0 wt% MWCNTs. The highest electrical conductivity was 2.4 × 10−5 S cm−1 at 8.0 wt% MWCNTs. Both the thermal and electrical conductivities showed percolation behavior with the percolation thresholds at 6 and 5 wt%, respectively. The MWCNTs synthesized by microwave method gave a good power economy in comparison to MWCNTs obtained by chemical vapor deposition (CVD) on NiMg catalyst. Microwave‐synthesized MWCNTs showed high stability at a potential of 250 V in an electrical resistance heater application due to the presence of Fe on the surface of MWCNTs. The developed heater can effectively operate at 220 V, which enables the use of the tubes in household appliances, such as heat fans, irons, and washing machines.Highlights Synthesis of MWCNTs by microwave plasma treatment of ferrocene and graphite. Characterization of MWCNTs by different techniques. Concentration dependence of electro‐ and thermal conductivity of MWCNTs in elastomers. Electro‐physical parameters studies of elastomers modified with MWCNTs. Heat generation studies in elastomeric matrix with MWCNTs.

Effect of oxygen-supply on the reburning reactivity of pyrolyzed residual from sub-bituminous coal: A reactive force field molecular dynamics simulation

The lean-oxygen combustion of incompletely pyrolyzed char dominated at the combustion front of coalfield fires. Functional group distributions and carbon micro-crystal dimensions were characterized for developing the molecular model (C184H124N2O16S) of pyrolyzed coal char at 400 °C (TLG P400). The overall combustion process of TLG P400 under various oxygen/fuel ratios (Ω) were simulated in an intuitive approach with ReaxFF. The findings indicated that the primary carbon-containing intermediates transformed from large pieces of aromatic fragments C40+ with self-similarity to heavy components of C15–C40 in initial combustion stage, then to light components of C5–C14 in late stage. With Ω increasing from 1.0 to 5.0, the final carbon conversion was found to rise from 78.50% to 96.32%, while the CO/CO2 ratio in the products sharply decreased from 2.575 to 0.213. The apparent activation energy was calculated as 194.49 kJ/mol for TLG P400 combustion at Ω = 1.0. Higher oxygen concentration enhanced the adsorption proportion of edge carbon, resulting in the generation of unstable intermediates featuring meta- or para-semiquinone. These transformations promoted the detachment of edge carbon and weakened the bottle-neck effect of the single-benzene ring on rapid oxidation. This study provides valuable insights into combustion mechanism and monitoring approaches for controlling coalfield fires.

Oxidation performance and limitations of additively manufactured SiC/Si─O─C composites at elevated temperatures

AbstractSiC preforms were infiltrated with polycarbosiloxane preceramic polymer to create low‐cost SiC—SixOyCz matrix composites for possible high temperature application. The effect of specimen annealing conditions on the steam and air oxidation resistance was analyzed. Air exposures from 900–1500°C showed stability of the SixOyCz matrix phase with moderate oxidation resistance. After 900°C exposures, oxidation of the composite is primarily limited to the matrix phase, and only at 1200 and 1500°C was SiC consumption visualized. Steam cycle exposures at 1200°C resulted in rapid linear oxidation of the composites with induced specimen swelling from volume expansion associated with internal oxidation. Specimens annealed in argon were found to be the most oxidation resistant due to increased matrix crystallinity and carbon retention. The results of this work were used to develop clear strategies for improving the high‐temperature properties of SiC—SixOyCz composites.

Combining heterointerface/surface oxygen vacancies engineering of bismuth oxide to synergistically improve its solar water splitting performance

Solar-powered photoelectrochemical (PEC) water splitting is recognized as a strategy for addressing fossil resource and global warming concerns. The purpose of this paper is to demonstrate for the first time a facile method to fabricate dendritic nanostructured (DN) Bi:Bi2O3 heterointerface engineering junctions that possess abundant surface oxygen vacancies (OVs, DN Bi:Bi2O3-OVs/FTO), with outstanding PEC performance. The surface OVs serve as shallow donors and active reaction sites, whereas the Bi-metal bridges are used for fast electron transport. Furthermore, surface OVs can enhance the surface features of Bi:Bi2O3 heterointerfaces and boost their electrical conductivity and donor density. This greatly enhances electrolyte ion and electron mobility, resulting in rapid water oxidation reactions at the Bi:Bi2O3/electrolyte interfaces. By combining the Bi:Bi2O3 heterointerface junction and surface OVs, we are able to create an effective photoanode with 95 % charge injection efficiency, applied bias photon-to-current efficiency (ABPE) of 0.112 %, and a photocurrent response of 0.334 mA.cm−2 at 1.23 V vs. the reversible hydrogen electrode (RHE), which represents improvements of about 4.5 and 10 folds over that of pure DN Bi2O3 photoanode. It is possible to construct a variety of unique nanostructured electrodes with adjustable optical and electronic properties to be used in solar cells, energy storage, and PEC applications.

Rapid arsenite oxidation by Paenarthrobacter nicotinovorans strain SSBW5: unravelling the role of GlpF, aioAB and aioE genes.

A novel arsenite resistant bacterial strain SSBW5 was isolated from the battery waste site of Corlim, Goa, India. This strain interestingly exhibited rapid arsenite oxidation with an accumulation of 5mM arsenate within 24h and a minimum inhibitory concentration (MIC) of 18mM. The strain SSBW5 was identified as Paenarthrobacter nicotinovorans using 16S rDNA sequence analysis. Fourier-transformed infrared (FTIR) spectroscopy of arsenite-exposed cells revealed the interaction of arsenite with several important functional groups present on the cell surface, possibly involved in the resistance mechanism. Interestingly, the whole genome sequence analysis also clearly elucidated the presence of genes, such as GlpF, aioAB and aioE encoding transporter, arsenite oxidase and oxidoreductase enzyme, respectively, conferring their role in arsenite resistance. Furthermore, this strain also revealed the presence of several other genes conferring resistance to various metals, drugs, antibiotics and disinfectants. Further suggesting the probable direct or indirect involvement of these genes in the detoxification of arsenite thereby increasing its tolerance limit. In addition, clumping of bacterial cells was observed through microscopic analysis which could also be a strategy to reduce arsenite toxicity thus indicating the existence of multiple resistance mechanisms in strain SSBW5. In the present communication, we are reporting for the first time the potential of P. nicotinovorans strain SSBW5 to be used in the bioremediation of arsenite via arsenite oxidation along with other toxic metals and metalloids.

MACHINE LEARNING APPLICATION IN RESPONSE TO DISASTER RISK REDUCTION OF FOREST AND PEATLAND FIRE

Peat forest is a natural swamp ecosystem containing buried biomass from biomass deposits originating from past tropical swamp vegetation that has not been decomposed. Once it burns, smoldering peat fires consume huge biomass. Peat smoldering fires are challenging to extinguish. These will continuously occur for weeks to months. Experts and practitioners of peat smoldering fires are the most recommended effort to prevent them before they occur with the strategy: 'detect early, locate the fire, deliver the most appropriate technology.' Monitoring methods and early detection of forest and land fires or 'wildfire' have been highly developed and applied in Indonesia, for example, monitoring with hotspot data, FWI (Fire Weather Index), and FDRS (Fire Danger Rating System). These 'physical simulator' based methods have some weaknesses, and soon such methods will be replaced by the Machine Learning method as it is developing recently. What about the potential application of Machine Learning in the forest and land fires, particularly smoldering peat fires in Indonesia? This paper tries to answer this question. This paper recommends a conceptual design: impact-based Learning for Disaster Risk Reduction (DRR) of Forest, Land Fire, and Peat Smouldering.

Rapid and Versatile Biosensing of Liposome Encapsulation Efficiency Using Electrical Conductivity Sensor.

Liposomes are prominent nanosystems for drug delivery, with potential extending beyond isolated drugs. Ethanol-aqueous plant extracts can be encapsulated within liposomes to protect bioactive compounds (secondary metabolites) from rapid oxidation and enable sustained release. Determining which compound classes are present in each extract and the encapsulation efficiency (EE) of these extracts in liposomes is crucial for nanocarrier functionality. This involves assessing the ratio of bioactive substances within liposomes to the total content. However, quantifying EE for non-isolated compounds poses challenges due to the need for advanced analytical equipment and biosensing approaches. This study introduces an innovative method for EE quantification, using a conductivity electrode (k = 0.842/cm) to establish an EE biosensing technology. By correlating dynamic light scattering (DLS), zeta potential (ZP), and electrical conductivity (Cnd) data with the conductivity meter's calibration curve, a robust relationship between the free extract concentration and Cnd (r2 ≥ 0.950) was established. Lavender-loaded liposomes demonstrated an EE of 56.33%, while wormwood and oregano formulations exhibited high EEs of 94.33% and 91.70%, respectively. In contrast, sage-loaded liposomes exhibited an inadequate EE, encapsulating only approximately 0.57% of the extract. The straightforward quantification of the free extract within liposome formulations, compared to more complex approaches, could facilitate EE determination and support future characterizations.

PL02.1.A DELINEATING AND TARGETING A NOVEL METABOLISM-BASED POST-TRANSLATIONAL MECHANISM REGULATING THE ABUNDANCE OF THE ‘UNDRUGGABLE’ ONCOPROTEIN C-MYC IN MEDULLOBLASTOMA

Abstract BACKGROUND Brain tumors are the leading cause of cancer death in children, and medulloblastoma (MB) is one of the most common pediatric central nervous system malignancies. Amplification of the c-MYC oncogene is frequently observed in the most aggressive and lethal subgroup of this disease, group 3 (G3), but not in other subgroups. Patients that have G3 MB tumors with high c-MYC abundance are more likely to present as metastatic and are prone to develop fatal recurrent tumors. Unfortunately, the functional ubiquity and disordered structure of c-MYC makes it difficult to target for cancer treatment. Therefore, it is critical to identify novel, out-of-the-box strategies to suppress oncogenic c-MYC in highly aggressive G3 MB brain tumors. Recently, metabolism has emerged as a major regulator of overall cellular signaling processes through post-translational and epigenetic mechanisms. While c-MYC is known to regulate cellular metabolism, whether metabolism plays a role in reciprocally supporting enhanced c-MYC abundance in cancer is unknown. We hypothesize that an intrinsic feedback mechanism may exist where metabolic activity modulates c-MYC abundance that could be exploited as a therapeutic strategy to improve outcomes for G3 MB patients. MATERIAL AND METHODS Using various well-characterized G3 MB cells, patient-derived G3 MB cells, orthotopic intracerebellar xenograft models, patient tumor bioinformatics, detailed biochemical characterization, and point-mutation analyses, we have identified a novel metabolism-dependent post-translational modification that regulates c-MYC stability in G3 MB. RESULTS In-depth molecular analyses unveiled that c-MYC is susceptible to oxidation and proteasomal degradation under conditions of metabolic stress. Targeting mitochondrial respiration via inhibition of complex-I promotes the accumulation of reactive oxygen species (ROS) and leads to rapid cysteine oxidation and proteasomal degradation of c-MYC in G3 MB cells, but not normal human brain astrocytes or neural stem cells (NSCs). Point mutation analysis combined with biochemical oxidation assays identified the specific cysteine residues of c-MYC that are susceptible to oxidation and ultimately responsible for enhanced c-MYC degradation following complex-I inhibition. Importantly, oral administration of a blood-brain barrier permeable complex-I inhibitor impaired the growth of intracerebellar MB xenograft tumors in mice, significantly prolonging animal survival. CONCLUSION Altogether, these findings unveil a novel mechanism through which metabolism regulates the post-translational stability of c-MYC and provides insights for designing rationale therapeutic strategies for the treatment of MB patients. SUPPORT This work is supported by a project grant from the Canadian Institutes of Health Research (CIHR).

Coaxial Electrospun Tai Chi-Inspired Lithium-Ion Battery Separator with High Performance and Fireproofing Capacity.

Organic flame-retardant-loaded battery separator offers a new opportunity for battery safety. However, its poor thermal stability still poses serious safety issues. Inspired by Tai Chi, an "internal-cultivating and external-practicing" core-shell nanofibrous membrane was prepared by coaxial electrospinning, wherein the shell layer was a mixture of polyvinylidene fluoride, silicon dioxide (SiO2), and graphene oxide (GO) and the core layer contained triphenyl phosphate (TPP). SiO2 and GO enhanced the thermal stability and electrochemical performance. The encapsulated TPP prevented heat transfer and the degradation of electrochemical performance caused by its direct dissolution. This separator exhibited outstanding thermal stability and flame retardancy: it did not burn and remained relatively intact (91.2%) in an open flame for 15 s. The battery assembled with a composite separator showed excellent performance: the initial capacity reached 164 mA h/g and maintained 95% after 100 charge-discharge cycles. This novel strategy endows high-performance lithium batteries with relatively higher safety.