Experimental Burn Research Articles

GAMBUT field measurement of emissions from a tropical peatland fire experiment: from ignition to spread to suppression

Background Accurate quantification of emissions from peatland wildfire is crucial for understanding their feedback to the atmospheric and Earth system. However, current knowledge on this topic is limited to a few laboratory and field studies, which report substantial variability in terms of the fire emission factors (EFs). Aims We aim to understand how emissions vary across the life cycle of a peatland fire. Methods In August/September 2018, we conducted the largest and longest to-date field-scale experimental burn on a tropical peatland in Sumatra, Indonesia. Field measurements of gas emissions from the fire experiment were conducted using an open-path Fourier transform infrared spectroscopy to retrieve mole fractions of 11 gas species. Key results For the first time, we calculated and reported EFs from 40 measurement sessions conducted over 2 weeks of burning, encompassing different fire stages (e.g. ignition, smouldering spread, and suppression) and weather events (e.g. rainfall). Our findings provide field evidence to indicate that EFs vary significantly among fire stages and weather events. We also observed that the heterogeneous physicochemical properties of peatland site (e.g. moisture content) influenced the EFs. We also found that modified combustion efficiency was highly sensitive to complex field variables and could introduce large uncertainties when determining the regimes of a peat fire. Conclusions and implications Further studies to investigate peat fire emissions are needed, and more comprehensive mapping of peatland heterogeneity and land use for emissions inventories, accounting for spatial and temporal variability in EFs since the initiation of a fire event is required.

Wound Healing Activity of Two Honeys from the Southern Regions of Senegal (Casamance)

Aim: The aim of this study was to evaluate the healing activity of two honeys from Casamance (Senegal) in a second-degree experimental burn model in the Wistar strain rat. Methodology: Experimental burns were induced using a metal cylinder 3 cm in diameter and heated for 5 min. The cylinder was applied for 20 seconds, pressing lightly on the surface of the rats' shaved skin to induce second-degree burns. Results: The daily application of honey induces a healing dependent on concentration and typology. The healing rate is higher with AF, with a score of 0.60 ± 0.48 vs 1.00 ± 0.00 for MZ which induces almost complete tissue repair after 21 days of treatment. Conclusion: The results of this study demonstrate the use of traditional honey in wound healing and burns.

Repeated Tree Inventories of Pine Forests in South Florida's Big Cypress National Preserve.

The natural forest ecosystems of South Florida, USA, support a high biodiversity of plant and animal species and provide valuable ecosystem services. However, these ecosystems remain poorly represented in global studies, primarily due to a paucity of standardized data. Here, we present previously unpublished data from 332 censuses of 54 permanent 1-ha tree inventory plots in the Racoon Point area of Big Cypress National Preserve, Florida, USA, including a total of nearly 100,000 measurements (diameter or height) of > 17,000 individual living trees and palms (with additional measurements of nearly 6000 dead pine snags) collected sporadically over a 19-year period (1993-2012). These data, which were originally collected as part of a project to investigate tree responses to different experimental burning regimes, provide unique insight into the diversity, composition, structure, and dynamics of South Florida's unique and endangered pine forest ecosystems. Data files include the species identity, size (dbh = diameter at breast height), and location of all trees ≥ 5 cm dbh in 54 individual tree plots. Additional data are provided about heights of palm trees, and the location and burn history of each plot. These data are freely available for noncommercial scientific use under a Creative Commons license; users are encouraged to cite this paper when using the data.

The impacts of fire vary among vertical strata: Responses of ant communities to long-term experimental burning.

Fire is a powerful tool for conservation management at a landscape scale, but a rigorous evidence base is often lacking for understanding its impacts on biodiversity in different biomes. Fire-induced changes to habitat openness have been identified as an underlying driver of responses of faunal communities, including for ants. However, most studies of the impacts of fire on ant communities consider only epigeic (foraging on the soil surface) species, which may not reflect the responses of species inhabiting other vertical strata. Here, we examine how the responses of ant communities vary among vertical strata in a highly fire-prone biome. We use a long-term field experiment to quantify the effects of fire on the abundance, richness, and composition of ant assemblages of four vertical strata (subterranean, leaf litter, epigeic, and arboreal) in an Australian tropical savanna. We first document the extent to which each stratum harbors distinct assemblages. We then assess how the assemblage of each stratum responds to three fire-related predictors: fire frequency, fire activity, and vegetation cover. Each stratum harbored a distinct ant assemblage and showed different responses to fire. Leaf litter and epigeic ants were most sensitive to fire because it directly affects their microhabitats, but they showed contrasting negative and positive responses, respectively. Subterranean ants were the least sensitive because of the insulating effects of soil. Our results show that co-occurring species of the same taxonomic group differ in the strength and direction of their response to fire depending on the stratum they inhabit. As such, effective fire management for biodiversity conservation should consider species in all vertical strata.

Experimental burn models for evaluating wound healing agents and its current situation and existing disadvantages: a literature review

BACKGROUND: Burns remain a crucial part of the structure of injuries in Russia and abroad. Therefore, providing high-quality medical care to burn victims is relevant. Despite the large number of proposed solutions to this condition, developments in the field of tissue engineering and medical materials science still lack standardization and consideration of specific features of animal burn models for their testing. Many studies showed minor and major disadvantages from a technical and descriptive point of view. AIM: To analyze and identify the main disadvantages of existing burn models to assess the effect of wound healing agents. MATERIALS AND METHODS: This article examines the search results in the databases Google Scholar and PubMed using the keywords “burns,” “rats,” “animal model,” and “wound healing.” Sixty publications were analyzed. RESULTS: Seven quality criteria for the animal burn model have been determined, which allow obtaining reliable results and reproducing the described experiment: indication of the terms of quarantine and conditions of keeping laboratory animals, detailed description of the technique of applying burn injury, presence of one burn on a laboratory animal, presence of a control biopsy, indication of the absolute value of the initial burn area, presence of surgical treatment of burn wounds, and correct use of formulas for the planimetric assessment of wound healing. CONCLUSIONS: A solution to the problem of creating a standardized model may be a more detailed description of techniques and following the proposed quality criteria.

Comparison of The Effectiveness of Thymoquinone, St. John Wort Oil and Silver Sulfadiazine in Experimental Burn Wounds.

We aimed to compare the effectiveness of thymoquinone (TQ), most important bioactive component of black cumin, St. John wort (SJW) oil, a traditional medicinal plant used in burns, and silver sulfadiazine (AgSD), well-known anti-inflammatory agent used in modern medicine, in an experimental burn rat-model. 63 Wistar-Albino rats were randomly divided into 9 groups (n=7). TQ, SJW were administered topically and systemically but AgSD was applied topically. Epithelialization, inflammatory cell response, granulation tissue, vascularization, and fibrosis were evaluated. Malondialdehyde (MDA), total antioxidant status (TAS), total oxidant status (TOS), vitamin E, 8-hydroxy-deoxyguanosine (8-OHdG), coenzyme Q10 (CoQ10) were analyzed in serum. Topical TQ accelerated theepithelialization, enabled granulation, vascularization and fibrosis in wounds (P=0.001). Topical and systemic TQ increased Vitamin-E levels (P=0.003) but reduced TOS and 8-OHdG levels (P=0.001). Topical SJW reduced granulation and vascularization. Topical and systemic SJW decreased TOS, MDA and 8-OHdG levels (P=0.001), but increased TAS (P=0.001), and Vitamin-E levels (P=0.003). Topical AgSD reduced TOS, 8-OHdG, MDA levels (P=0.001). Topical and systemic TQ demonstrated significant advantages in accelerating wound healing process, while also enhancing antioxidant defenses and reducing oxidative damage. SJW oil, particularly in topical application, improved epithelialization and antioxidant status but showed less efficacy in systemic use. AgSD, while effective in reducing oxidative stress, was less successful in promoting wound healing and appeared to delay granulation and fibrosis. TQ offers superior protective and healing benefits, SJW is effective locally but less so systemically, and AgSD should be used cautiously, potentially combined with antioxidants to mitigate its negative impact on wound healing.

Vegetation dynamics after fire in the Brazilian Campo Rupestre: Effects on native plant communities and flower harvesting

We investigated the impact of both early and late fires on native plant communities of the Campo Rupestre in the Sempre-Vivas National Park (PNSV, Brazil). Everlasting flower harvesters use late fires to stimulate flowering, while park managers have been implementing early fires to reduce flammable biomass and, therefore, the risk of wildfires. We aimed to explore the effects of fire on species composition, vegetation cover, and plant and flower stalks height to evaluate post-fire vegetation recovery, especially considering Comanthera species, which are highly valued by flower harvesters. The experimental design involved two areas (A1 and A2) in PNSV from May/2019 to January/2021. We installed eight 50 × 50 m plots in each area, being half submitted to experimental burnings and the other half unburned (control plots). A1 experienced early fire in May, and A2 a late fire in September. Initial phytosociological surveys revealed differences between A1 and A2, therefore, fire effects were treated separately for each area. In both A1 and A2, fire initially impacted species richness and abundance but the effect dissipated over time, with vegetation becoming similar to unburned plots. Fire also affected vegetation cover, which returned to its original condition within a year, influenced by seasonality and plant phenology. Plant communities experienced a temporary reduction in height (∼4 cm) in the months following fire, and recovered in the subsequent rainy season. However, a tendency for smaller plants persisted, and the average height of flower stalks took almost two years to fully recover. In general, the late fire conducted in A2 led to a slower recovery trajectory. These findings indicate rapid post-fire biomass recovery and minimal impact on plant species composition, highlighting the resilience of Campo Rupestre to single fires. Further studies are crucial to understand plant response to fires at different fire frequencies.

An experimental and numerical study of propyl acetate laminar combustion characteristics

The laminar burning characteristics of propyl acetate were investigated using the constant volume combustion experimental unit at the working conditions of 1, 2, and 4 bar and 390, 420, and 450 K over a wide range of equivalence ratios (0.7–1.4). Both experimental and numerical investigations were used to study the laminar combustion characteristics of propyl acetate. Also, a chemical mechanism was proposed in this work to numerically investigate the laminar combustion of propyl acetate. A comparison of this study and literature experimental burning velocity data with the proposed mechanism laminar burning velocity showed satisfactory agreement. Sensitivity investigations of the burning velocity and production rate analysis of the reactions revealed that the reaction that mostly produces OH, H, and O radicals significantly drives the combustion of propyl acetate and increases the laminar burning velocity. Moreover, fuel-related reaction R1086: H + PA ⇔ H2 + PA2J increased the laminar burning velocity but fuel-related reaction R1098: OH + PA ⇔ H2O + PAMJ decreased the burning velocity. The reaction pathway study showed that propyl acetate mainly decomposes to PAMJ radical, PA2J radical, PAEJ radical, propene, and acetic acid before it converts into other radicals. Also, it was shown that ally radicals and ketene are essential intermediates in the fuel conversion process of propyl acetate.

Casting light in the shadows: Exploring the influence of biological sex and age-at-death on heat-induced shrinkage in experimentally burned patellae

Burned human remains have been studied by both forensic anthropologists and bioarchaeologists to understand how fire impacts and alters bone in different scenarios. Heat-induced changes can occur including differences in colour and shrinkage, where the extent of the latter varies in different studies. The current study aimed to bring information regarding this topic and to observe how the individual’s biological sex and age at death impact shrinkage. The variability of shrinkage was analysed, relating to temperature and duration of burning. The sample comprised of the patellae of 32 individuals (18 [56.3 %] females and 14 [43.8 %] males) with age at death between 60 and 93 (age grouped in decades) from the sub-collection of experimentally burned skeletons, part of the 21st Century Identified Skeletal Collection (ISC/XXI). The right patellae were subjected to experimental burning at different temperatures and durations using an electric muffle furnace. Both the right and left patellae had three measurements taken, maximum height, maximum thickness and maximum width, with a digital calliper. The shrinkage percentage was higher in males and among the younger individuals (60–79 years old of both sexes). The values of standard deviation were high which indicates high variability. Shrinkage occurred at every temperature with bigger values observed in the patellae that had been subjected to temperatures over 800ºC. However, three patellae showed an increase in size at temperature under 800ºC. These findings align with previous studies where a non-linear correlation between shrinkage and exposure duration was found. It is essential to underscore that the percentage of shrinkage exhibits substantial variability even under identical temperature and duration conditions, highlighting the critical significance of meticulous experimental design and thorough analysis.

Observation of alpha-particles in recent D–T experiments on JET

The fusion reaction between deuterium and tritium, D(T,n)4 He is the main source of energy in future thermonuclear reactors. Alpha-particles (4 He-ions) born with an average energy of 3.5 MeV transferring energy to the thermal plasma during their slowing down, should provide the self-sustained D–T plasma burn. The adequate confinement of α-particles is essential to provide efficient heating of the bulk plasma and steady burning of a reactor plasma. That is why the fusion-born α-particle studies have been a priority task in the second D–T experiments (DTE2) on the Joint European Torus (JET) to understand the main mechanisms of their slowing down, redistribution and losses and to develop optimal plasma scenarios. JET with Be-wall and W-divertor, enhanced auxiliary heating systems and improved energetic-particle diagnostic capabilities, producing significant population of α-particles, provided the possibility for comprehensive studying of the α-particle behaviour. Selected results of the confined and lost α-particle measurements, evidence of α-particle self-heating and assessments of the fusion performance are presented in this paper giving an opportunity for further modelling and extrapolation to the International Thermonuclear Experimental Reactor and burning plasma reactors.

Fire and grazing interaction in a subhumid grassland: Effects on a dominant tussock grass

AbstractQuestionsHerbivory and fire are the main disturbance drivers in open ecosystems. The aim of this study was to evaluate the effects of fire, cattle grazing, and their interaction on structural traits and the Normalized Difference Vegetation Index (NDVI) of the tussock grass Saccharum angustifolium, and its temporal dynamics in a subhumid grassland.LocationGrasslands of the Eastern Hills, Uruguay.MethodsWe set three blocks (four plots of 300 m2 each) in a homogeneous grazed area dominated by S. angustifolium within a protected area. Each block presented the combinations that emerged from the two levels of cattle grazing (grazed/ungrazed) and burning (burned/unburned) factors. The experimental burning was carried out in the spring. Clump volume, number of flowering culms, NDVI of S. angustifolium, and soil variables were measured for 2 years.ResultsBurning efficiency (plant biomass burned of the total available) was 82%, burn intensity ranged from 178–610 kW m−1, and the soil temperature increased 40% compared with pre‐fire measurements. The volume of S. angustifolium clumps decreased with fire, and the difference between burned–unburned plots decreased with time. The burned–ungrazed treatment increased the number of S. angustifolium flowering culms. NDVI of S. angustifolium clumps increased 50% with fire, and then decreased with time. Soil temperature was higher in burned treatments, and moisture was higher in unburned treatments on some dates. Bulk density, for the 0–5‐cm depth, was 9% higher in burned than in unburned plots irrespective of grazing.ConclusionsOur results provide new data in favor of the management practice carried out by ranchers in Uruguayan grasslands dominated by S. angustifolium. Our data complement the evidence that a fire–grazing interaction can maintain grasslands in different phases of a stable state. Our results constitute a useful contribution for the managers/authorities of the protected area, and can be extrapolated to other tussock grass‐dominated grassland areas.

ON THE QUESTION OF THE EFFECT OF REGENERATION STIMULATION DRUGS ON THE RESTORATION OF THE SKIN IN CASE OF INJURY

Background. The study of the reaction of tissue (epidermis and dermis) to the medication of regeneration stimulants (МSR) in injuries is relevant both for the development of wound coatings and treatment regimens for the traumatic process. In this study, special attention is paid to the process of stimulation of stem cells in the hair papilla, which play an important role in the restoration of skin structures. The aim of the study was also to study the morphological changes of the epidermis and dermis in the dynamics of trauma. Materials and methods. To conduct the experiment, experimental groups were formed: a burn model without treatment; a burn model with a МSR preparation (oral administration and wound coating); an experimental group with a linear wound with МSR treatment, an experimental group similar reproduction of a wound without suturing with МSR, a control group similar reproduction of a wound without treatment with suturing, a control group - similar reproduction of the wound without treatment and without suturing. Animals were removed from the experiment by inhalation of ether vapors in accordance with the "Rules for carrying out work using experimental animals" and in accordance with the principles of the Helsinki Declaration of the World Medical Association (Declaration of Helsinki, and approved by the Institutional Review Board). Tissue fragments were taken from the site of thermal trauma and healthy tissue for the preparation of histological preparations. The production of paraffin histological sections with a thickness of 5-7 microns was carried out according to generally accepted standard methods. The sections were stained with hematoxylin and eosin. The photos were taken using the Vision Bio system (Epi 2014) and stained with hematoxylin-eosin, which were examined under x100 magnification. The obtained data were processed using MS Excel and Statgraphics software packages using generally accepted methods of statistics. Results. When reproducing thermal trauma In the control group on day 14, there is no epidermis in part of the visual fields within the studied material, the layers are replaced by connective tissue strands, scar tissue is visualized. The dermis is moderately edematous, with neutrophilic and lymphocytic infiltration is weakly expressed, in the papillary and reticular layer it is evenly represented, there are single apoptotic corpuscles. No areas of hemorrhage were detected, but the blood vessels were dilated. While in the experimental group there are signs of restoration of microcirculation with a large number of vessels and a more pronounced layer of the epidermis. When examining scars after a linear wound, it was found that animals who did not receive therapy have a thin scar, and in animals who received МSR, the consequences of surgical intervention are not visualized. Conclusion. The dynamics of the wound process was studied when using a prototype ointment containing a regeneration complex in the treatment of burn and linear wounds in an experiment. The effectiveness of the regenerative complex of a prototype ointment for the treatment of experimental burn and linear wounds in laboratory animals in comparison with the control group was revealed. It has been established that in the treatment of burn and linear wounds with experimental ointment, the healing period of burn wounds is reduced due to more active formation of the microcirculatory bed and the early onset of epithelization.

The 1986 Annaburroo experimental grassland fires: data

Background In 1986, CSIRO conducted a large program of experimental fires in grassland at Annaburroo Station, Northern Territory, Australia, with the objective of quantifying the effect of fuel condition (load and height) on fire behaviour. Aims This paper provides the data collected during this program, representing a unique set of observations and measurements of large, free-burning experimental fires conducted in a multi-factor experimental design. Methods Data are collated by experimental burn plot, providing detailed measurements of weather (wind speed, air temperature, relative humidity), fuel state (load, height, moisture content, curing) and fire behaviour (rate of spread, flame depth, flame height, head fire width), as well as processed information (e.g. steady-state rate of spread). Data availability The data are made available for free download on the CSIRO Data Access Portal (https://data.csiro.au/collection/csiro:58746) and include detailed metadata descriptions of the data and their structure, also provided in this article. Conclusions We have made the data available for fire behaviour researchers around the world to use in their research under the Creative Commons Attributions licence. It is hoped they will analyse these data and extract new and innovative insights to help improve our understanding of wildland fires burning in grass fuels.

XRF identification of sharp-force trauma in fresh and dry human bone under varied experimental heat conditions

Heat-induced fractures can be hard to distinguish from sharp force traumas. This challenge can negatively impact medico-legal analysis. The present study aimed to experimentally assess if X-ray fluorescence (XRF) can be used to detect chemical traces transferred from the blade of a sharp instrument onto both fresh and dry human bones. This was performed by inducing sharp force traumas with five different instruments on 20 fresh and 20 dry human clavicles. All bone samples were probed before and after experimental burning (at 500 °C, 700 °C, 900 °C and 1100 °C). Our results show that XRF is potentially useful for detecting iron traces in fresh human bone, both unburned and burned. However, we were not able to clearly detect iron traces from the blades in bones that have been previously inhumed, since exogenous iron acquired during diagenesis masks the iron traces originating from the blade.

Small‐scale fires interact with herbivore feedbacks to create persistent grazing lawn environments

Abstract Fire‐herbivory feedbacks strongly influence the formation of grazing lawns in savanna ecosystems. Preliminary findings suggest that small‐scale (<25 ha) fires can engineer grazing lawns by concentrating herbivores on the post‐burn green flush; however, the persistence of such grazing lawns over the longer term and without repeated fire is unknown. We used high‐resolution Light Detection and Ranging (LiDAR) to investigate the long‐term effects of fire manipulation on short grass structure (height, cover, volume and spatial continuity) and grazing lawn establishment in Kruger National Park, South Africa. We analysed the effects of fire exclusion and experimental burns applied over a 7‐year period (2013–2019) followed by a 1‐year cessation of burning at varying spatial scales during the early and late dry seasons. Fires contributed a fourfold increase in short grass cover, regardless of fire season or size. The distribution of grass height differed significantly between fire‐induced grazing lawns and recently unburnt parts of the landscape where controlled fires were excluded over the experimental period. The volume (corresponding to bulk density) of short grass on the landscape responded strongly to fires, with grass volume <20 cm in height increasing with both early and late dry season fires. Early dry season fires caused larger and more homogeneous short grass patches. Furthermore, early dry season fires were more influential in increasing the cover of the shortest grass height class (1–5 cm). Synthesis and applications. Our results demonstrate that fire‐induced grazing lawns can persist over the longer term, even when fires are no longer applied, leading to the creation of vertical and horizontal heterogeneity in the grass layer. Small‐scale fires, therefore, represent a feasible management approach to expanding grazing lawn extent, potentially benefiting grazer coexistence and diversity.

Bone color changes and interpretation of the temperature/duration of fire exposure to human remains in the forensic context

AbstractIn both the archeological and forensic literature, experimental data have been used to equate the color of burned bone with the temperature to which it was exposed. While this may be applicable in the tightly controlled oxidizing environment of a furnace or crematorium, it is not representative of the more realistic dynamic conditions of fire events involving structures, vehicles, outdoors, and so forth, that are encountered in forensic anthropology casework. In this piece, we review the literature at the cross section of bone color and temperature and compare it to our own observations from experimental burns. We generate a cautionary path forward for future research as well as interpretation in applied contexts. Implying temperature based on burned bone color ignores other significant variables that are related to the degradation of the bone's organic matrix like, the amounts and types of fuels, duration, fluctuations of temperature, oxygen level of the environment, byproducts of combustion, and other variables unique to each scene. Research results on bone color and temperature derived from controlled environments using non‐fleshed bone samples, are not applicable for use in forensic casework involving burned human remains from fleshed bodies. We argue that to do so distracts from other contributing variables and information that can be derived from the analysis of fire patterns on burned human remains and burned bones. Finally, we caution about using bone color alone to estimate temperatures of the fire, which makes incorrect assumptions about fire behavior and could jeopardize court testimony if this method is used as a standard. We raise three issues if a direct correlation between temperature and bone color are used in court: (1) other important factors are ignored, (2) a universal unvaried exposure of the body is assumed, and (3) the expert risks impeachment given conflicting data on the correlation.This article is categorized under: Forensic Medicine > Death Scene Investigation Forensic Anthropology > Taphonomic Changes and the Environment

Restoring landscape burning is compatible with conservation and livestock production in a southeast Australian grassland fragment

Abstract Lowland grassland fragments in southeast Australia are valued for both sheep grazing and conservation. Many fragments are now rarely burnt, despite being shaped by millennia of Aboriginal fire‐use. Restoring fire could potentially reduce fuels, control exotic plant species, promote native species and renew Aboriginal cultural burning. However, this requires understanding of how fire and large herbivores, both native and exotic, are coupled and influence vegetation. We implemented a single round of low‐intensity experimental burns in an area of remnant grassland and patchy eucalypt woodlands in Tasmania that is managed for conservation, albeit intermittently grazed by sheep, as well as by native and exotic wild herbivores. We compared herbivore activity between burnt and unburnt areas over 2 years using cameras and scat transects, and assessed how fire and herbivory influenced herbaceous biomass and the cover of broad vegetation classes with and without herbivore exclusion. Contrary to expectations, burnt areas did not disproportionately attract the main herbivores: domestic sheep, introduced deer and native wallabies. In the predominant grassy sward, grazing and fire both reduced herbaceous biomass but we found no support for our hypothesis that grazing reduces biomass more strongly after burning. This contrasts with isolated patches of Poa tussock grassland, where fire reduced biomass much more strongly than grazing, and grazing effects on biomass were more pronounced following burning. The cover of broad vegetation classes was little affected by burning, but excluding herbivores increased exotic grass cover in both burnt and unburnt plots. Practical implication. In degraded fragments of lowland native grassland, burning and grazing do not necessarily act as strongly synergistic disturbances. Grazing by sheep and wild herbivores can help to control exotic grasses and reduce herbaceous biomass, although burning is much more effective than grazing for reducing biomass of unpalatable Poa tussock grassland. Our results suggest that returning occasional low‐intensity fires to our study system, and other degraded grassland‐woodland fragments, can be compatible with livestock production and conservation goals, but this requires caution and adaptive management.

Investigation on the intrinsic instabilities of ethyl methyl carbonate flames

The intrinsic instabilities of ethyl methyl carbonate flames are investigated at equivalence ratios (0.6–1.8) and initial pressures (70–160 kPa) by using a 36-liter constant volume combustion chamber. The unstable laminar premixed flame is evaluated by the laminar burning velocity, explosion characteristics, flame cellularity, and flame self-acceleration. The experimental laminar burning velocity is well reproduced by the chemical kinetic mechanism. The extent of cellularization characterized by the crack length and average cell area non-monotonically varies with increasing equivalence ratio but monotonically increases with increasing initial pressure. Meanwhile, the critical flame radius for the onset of cellularity exhibits non-monotonic variation with the equivalence ratio, while it decreases monotonically with increasing initial pressure. The experimental critical Peclet number and critical flame radius are well captured by flame stability theory. The linear correlation between the critical Peclet number and the Markstein number is Pecl = 26.46 Ma + 122.22. In addition, the dependence of the critical Karlovitz number on the Markstein number is predicted as Kacl = 0.0226e-0.0880Ma. The flame self-acceleration increases as the flame instabilities increase. The acceleration exponent and fractal dimension are smaller than 1.5 and 2.33, respectively, which are the suggested values for flame self-turbulization.

The Effects of Ellagic Acid on Experimental Corrosive Esophageal Burn Injury.

This study aimed to investigate the antioxidant effect of Ellagic acid (EA) on wound healing in sodium hydroxide (NaOH)-induced corrosive esophageal burn injury. The interaction networks and functional annotations were conducted using Cytoscape software. A total of 24 Wistar albino rats were divided into control, corrosive esophageal burn (CEB) and CEB + EA groups. Burn injury was created by 20% NaOH and 30 mg/kg EA was per oral administered to rats. At the end of the 28-day experimental period, Malondialdehyde (MDA) content was measured. Esophageal tissue samples were processed for histological staining. The EA-target interaction network was revealed to be involved in regulating crucial cellular mechanisms for burn wound healing, with epidermal growth factor (EGF) identified as a central mediator. An increase in animal weight in the CEB + EA group was observed in the EA-treated group after CEB injury. Burn injury increased MDA content, but EA treatment decreased its level after CEB injury. Stenosis index, collagen degeneration, inflammation, fibrosis and necrosis levels were increased after CEB injury. EA treatment improved histopathology in the CEB + EA group compared to the CEB group. The expression of EGF was decreased in the CEB group but upregulated in the EA-treated group, suggesting a potential involvement of EA in cellular processes and tissue regeneration. EA, through its antioxidative and tissue regenerative properties, significantly contributes to alleviating the adverse effects of CEB injury, promoting wound healing.

Efficiency of ozone (O3) therapy on experimental acidic skin burns in rats

In this study, it was aimed to investigate the efficacy of O3 therapy in experimentally induced HF skin burns in rats. A total of 20 healthy male Wistar Albino rats (weighing 250-300 g, aged 16 weeks) were used as the material of the study. They were divided into two groups (as experimental and control groups) of 10 rats which were housed individually and fed ad libitum. Hydrofluoric acid (HF) skin burns were induced in all animals. The ozonized (20 µg O3/mL) liquid vaseline was applied topically for seven days to the experiment group as well as parallelly, a saline solution was applied to the control group. In the histopathologic evaluation, inflammation, vascularization, epithelial regeneration and fibrosis were evaluated.
 The epithelial proliferation and collagenization were higher and statistically significant in the experimental group, while the infiltration was higher and statistically significant in the control group. As a result of this study, it was observed that ozone plays an important role in the tissue repair process in chemical burns. The increase of fibroblast activation and re-epithelization in the experimental group demonstrated that ozone therapy could be suggested as first aid in HF skin burns. It was concluded that more studies on ozone are needed to shed light on the subject.