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Frontiers in Veterinary Science 2024Fire-related deaths are usually a consequence of carbon monoxide (CO) poisoning or shock from thermal injuries. In humans, high levels of carboxyhemoglobin (COHb)...
Fire-related deaths are usually a consequence of carbon monoxide (CO) poisoning or shock from thermal injuries. In humans, high levels of carboxyhemoglobin (COHb) concentrations in the blood can support a diagnosis of CO poisoning. In veterinary medicine, few studies investigated the pathological changes and blood COHb% in fire victims, and no data are available on post-mortem changes in blood gas composition due to fire. This study aims to investigate the pathological changes and COHb levels in both animal victims of fire and cadavers experimentally exposed to fire. For this purpose, dogs were selected and subdivided into three groups. Group A comprised 9 adult dogs, and Group B comprised 7 puppies that died under fire-related conditions. Group C was represented by 4 dog cadavers experimentally exposed to heat and smoke. A complete macroscopic, histological, and COHb evaluation were performed on each animal. Animals in Groups A and B showed cherry-red discoloration, thermal-injuries and soot deposits along the respiratory tract. Animals in Group C showed thermal injuries and soot deposits limited to the upper respiratory tract. The mean COHb% values in cadavers in Group C were lower than those observed in the other groups but higher compared to the values detected before the heat and smoke treatment. These findings suggest that both pathological changes and COHb analysis are valid tools for investigating fire-related deaths in dogs. However, the increase of COHb levels in cadavers exposed post-mortem to heat and smoke highlights how the COHb analysis should always be evaluated together with macroscopical and microscopical findings to avoid significant misjudgments in investigating fire-related fatalities in veterinary forensic practice.
PubMed: 38835893
DOI: 10.3389/fvets.2024.1396540 -
Journal of Colloid and Interface Science Oct 2024This present work demonstrated the functional transformation of 3D printed metal substrates into a new family of Surface-enhanced Raman Scattering substrates, a...
This present work demonstrated the functional transformation of 3D printed metal substrates into a new family of Surface-enhanced Raman Scattering substrates, a promising approach in developing SERS-based Point-of-care (PoC) analytical platforms. l-Powder Bed Fusion (l-PBF, Additive manufacturing or 3D printing technique) printed metal substrates have rough surfaces, and exhibit high thermal stability and intrinsic chemical inertness, necessitating a suitable surface functionalization approach. This present work demonstrated a unique multi-stage approach to transform l-PBF printed metal structures as recyclable SERS substrates by colloidal carbon templating, chemical vapor deposition, and electroless plating methods sequentially. The surface of the printed metal structures was functionalized using the colloidal carbon soot particles, that were formed by the eucalyptus oil flame deposition method. These carbon particles were shown to interact with the metals present in the printed structures by forming metal carbides and function as an adlayer on the surface. Subsequent deposition of TiO onto these templates led to strong grafting of TiO and retaining the fractal structure of the soot template onto the metal surface. Electroless deposition of silver nanoparticles resulted in the formation of fractally structured TiO/Ag nanostructures and these functionalized printed metal structures were shown as excellent SERS substrates in enhancing the vibrational spectral features of Rhodamine B (RhB). The presence of TiO photocatalyst on the surface was shown to remove the RhB analyte from the surface under photochemical conditions, which enables the regeneration of SERS activity, and the substrate can be recycled. The migration of metals from the printed metal structures into the fractally ordered TiO/Ag nanostructures was found to enhance the photocatalytic activity and increase the recyclability of these substrates. This study demonstrates the potential of 3D-printed Inconel metal substrates as next-generation recyclable SERS platforms, offering a substantial advancement over traditional colloidal, thin-film, flexible, and hard SERS substrates.
PubMed: 38815369
DOI: 10.1016/j.jcis.2024.05.181 -
Environmental Science & Technology Jun 2024Residential biomass burning is an important source of black carbon (BC) exposure among rural communities in low- and middle-income countries. We collected 7165 personal...
Residential biomass burning is an important source of black carbon (BC) exposure among rural communities in low- and middle-income countries. We collected 7165 personal BC samples and individual/household level information from 3103 pregnant women enrolled in the Household Air Pollution Intervention Network trial. Women in the intervention arm received free liquefied petroleum gas stoves and fuel throughout pregnancy; women in the control arm continued the use of biomass stoves. Median (IQR) postintervention BC exposures were 9.6 μg/m (5.2-14.0) for controls and 2.8 μg/m (1.6-4.8) for the intervention group. Using mixed models, we characterized predictors of BC exposure and assessed how exposure contrasts differed between arms by select predictors. Primary stove type was the strongest predictor ( = 0.42); the models including kerosene use, kitchen location, education, occupation, or stove use hours also provided additional explanatory power from the base model adjusted only for the study site. Our full, trial-wide, model explained 48% of the variation in BC exposures. We found evidence that the BC exposure contrast between arms differed by study site, adherence to the assigned study stove, and whether the participant cooked. Our findings highlight factors that may be addressed before and during studies to implement more impactful cookstove intervention trials.
Topics: Humans; Female; Pregnancy; Adult; Cooking; Air Pollution, Indoor; Soot; Carbon; Air Pollutants; Environmental Exposure
PubMed: 38810212
DOI: 10.1021/acs.est.3c09991 -
ACS Omega May 2024In this study, simulations were carried out to study the combustion characteristics within a 600 MW W-shaped pulverized coal boiler under O/N and O/CO atmospheres. The...
In this study, simulations were carried out to study the combustion characteristics within a 600 MW W-shaped pulverized coal boiler under O/N and O/CO atmospheres. The objective of this work is to develop and validate a novel model for pulverized coal combustion under O-enriched conditions, specifically optimized for the O/CO atmosphere. The innovation in this model lies in the precise calibration of kinetic constants for soot nucleation and surface growth rates, enabling a more accurate simulation of flame characteristics (such as the flame temperature and soot volume fraction) under O-enriched combustion conditions. The study reveals that an increase in the O concentration significantly reduces the combustion flame height and flame penetration depth, thereby enhancing the local temperature inside the furnace. Moreover, at higher oxygen concentrations, the high levels of OH and O accelerate the oxidation reaction rate and shift the high-temperature zone upward. Subsequently, the maximum value of the nucleation rate increases. Therefore, compared to those of the O/N atmospheres, in the O/CO atmospheres, the peak volume fractions of soot decreased by 0.72, 25.5, and 15.9% for oxygen contents of 21, 30, and 40%, respectively. This demonstrates the impact of the oxidizing environment on soot production. Therefore, this study delves into the effects of oxygen concentration and temperature on soot formation and provides a new model for better predicting and optimizing combustion processes in industrial applications.
PubMed: 38799372
DOI: 10.1021/acsomega.4c00285 -
Environmental Pollution (Barking, Essex... Aug 2024High uncertainty in optical properties of black carbon (BC) involving heterogeneous chemistry has recently attracted increasing attention in the field of atmospheric...
High uncertainty in optical properties of black carbon (BC) involving heterogeneous chemistry has recently attracted increasing attention in the field of atmospheric climatology. To fill the gap in BC optical knowledge so as to estimate more accurate climate effects and serve the response to global warming, it is beneficial to conduct site-level studies on BC light absorption enhancement (E) characteristics. Real-time surface gas and particulate pollutant observations during the summer and winter over Wuhan were utilized for the analysis of E simulated by minimum R squared (MRS), considering two distinct atmospheric conditions (2015 and 2017). In general, differences in aerosol emissions led to E differential behaviors. The summer average of E (1.92 ± 0.55) in 2015 was higher than the winter average (1.27 ± 0.42), while the average (1.11 ± 0.20) in 2017 summer was lower than that (1.67 ± 0.69) in winter. E and R (representing the mass ratio of non-refractory constituents to elemental carbon) constraints suggest that E increased with the increase in R under the ambient condition enriched by secondary inorganic aerosol (SIA), with a maximum growth rate of 70.6% in 2015 summer. However, E demonstrated a negative trend against R in 2017 winter due to the more complicated mixing state. The result arose from the opposite impact of hygroscopic SIA and absorbing OC/irregular distributed coatings on amplifying the light absorbency of BC. Furthermore, sensitivity analysis revealed a robust positive correlation (R > 0.9) between aerosol chemical compositions (including sulfate, nitrate, ammonium and secondary organic carbon), which could be significantly perturbed by only a small fraction of absorbing materials or restructuring BC through gaps filling. The above findings not only deepen the understanding of BC, but also provide useful information for the scientific decision-making in government to mitigate particulate pollution and obtain more precise BC radiative forcing.
Topics: Soot; Air Pollutants; Aerosols; Environmental Monitoring; Seasons; Particulate Matter; Light; Carbon; China; Atmosphere
PubMed: 38761879
DOI: 10.1016/j.envpol.2024.124175 -
Journal of Aerosol Science May 2024The U. S. Environmental Protection Agency in collaboration with the U. S. Air Force Arnold Engineering Development Complex conducted the VAriable Response In Aircraft...
The U. S. Environmental Protection Agency in collaboration with the U. S. Air Force Arnold Engineering Development Complex conducted the VAriable Response In Aircraft nvPM Testing (VARIAnT) 3 and 4 test campaigns to compare nonvolatile particulate matter (nvPM) emissions measurements from a variety of diffusion flame combustion aerosol sources (DFCASs), including a Cummins diesel engine, a diesel powered generator, two gas turbine start carts, a J85-GE-5 turbojet engine burning multiple fuels, and a Mini-CAST soot generator. The VARIAnT research program was devised to understand reported variability in the ARP6320A sampling system nvPM measurements. The VARIAnT research program has conducted four test campaigns to date with the VARIAnT 3 and 4 campaigns devoted to: (1) assessing the response of three different black carbon mass analyzers to particles of different size, morphology, and chemical composition; (2) characterizing the particles generated by 6 different combustion sources according to morphology, effective density, and chemical composition; and (3) assessing any significant difference between black carbon as determined by the 3 mass analyzers and the total PM determined via other techniques. Results from VARIAnT 3 and 4 campaigns revealed agreement of about 20% between the Micro-Soot Sensor, the Cavity Attenuated Phase Shift (CAPS PM) monitor and the thermal-optical reference method for elemental carbon (EC) mass, independent of the calibration source used. For the LII-300, the measured mass concentrations in VARIAnT 3 fall within 18% and in VARIAnT 4 fall within 27% of the reference EC mass concentration when calibrated on a combustor rig in VARIAnT 3 and on an LGT-60 start cart in VARIAnT 4, respectively. It was also found that the three mass instrument types (MSS, CAPS PM, and LII-300) can exhibit different BC to reference EC ratios depending on the emission source that appear to correlate to particle geometric mean mobility diameter, morphology, or some other parameter associated with particle geometric mean diameter (GMD) with the LII-300 showing a slightly stronger apparent trend with GMD. Systematic differences in LII-300 measured mass concentrations have been reduced by calibrating with a turbine combustion as a particle source (combustor or turbine engine). With respect to the particle size measurements, the sizing instruments (TSI SMPS, TSI EEPS, and Cambustion DMS 500) were found to be in general agreement in terms of size distributions and concentrations with some exceptions. Gravimetric measurements of the total aerosol mass produced by the various DFCAs differed from the reference EC, BC and integrated particle size distribution measured aerosol masses. The measurements of particle size distributions and single particle analysis performed using the miniSPLAT indicated the presence of larger particles (≳150 nm) having more compact morphologies, higher effective density, and a composition dominated by OC and containing ash. This increased large particle fraction is also associated with higher values of single scattering albedo measured by the CAPS PM instrument and higher OC measurements. These measurements indicate gas turbine engine emissions can be a more heterogeneous mix of particle types beyond the original E-31 assumption that engine exit exhaust particles are mainly composed of black carbon.
PubMed: 38751612
DOI: 10.1016/j.jaerosci.2024.106352 -
Maedica Mar 2024Burned corpses are of medicolegal importance as circumstances may suggest means that are used for committing or concealing homicidal death or death occurring due to...
Burned corpses are of medicolegal importance as circumstances may suggest means that are used for committing or concealing homicidal death or death occurring due to accidental causes. Postmortem burns, which may include homicidal burns (torch murder) or burns used to conceal the crime, are committed with the motive of identity destruction, transposing the cause and manner of death and destruction of evidence. The present study aimed to analyse the cases of postmortem burns in the context of the cause of death, manner of death and circumstances pertaining to death. This is a retrospective study performed in the Government Medical College δ Hospital, Aurangabad (MH), India, between 1 January 2009 - 31 December 2016. Cases involving burn injuries were examined in detail by autopsy reports, toxicological analyses, crime scene investigation and police records submitted at the Institute's office. A careful examination of vitality signs of burns, soot deposition in the lower respiratory tract and the presence of other fatal injuries was performed for each case. Cases exposed to fire before death were all excluded. Similarly, bodies being charred to such an extent to prevent distinguishing the vitality of burns were also excluded. Postmortem burns were recorded in 13 cases (0.46%) of deceased bodies to cover homicides. Females were reported to be more commonly involved and more in a household environment. Head injury was the most common cause of death, followed by death due to asphyxia due to any means. The findings of the present study reinforce the fact that burning cannot always effectively destroy the evidence, hindering the perpetrator from covering up the crime. Apart from the evidence at autopsy, a transdisciplinary approach must be initiated with detailed crime scene investigation, toxicology, ascertaining the cause of death with analyses of fatal injuries and contributory data for identification of the deceased.
PubMed: 38736924
DOI: 10.26574/maedica.2024.19.11.80 -
PloS One 2024In software development, it's common to reuse existing source code by copying and pasting, resulting in the proliferation of numerous code clones-similar or identical...
In software development, it's common to reuse existing source code by copying and pasting, resulting in the proliferation of numerous code clones-similar or identical code fragments-that detrimentally affect software quality and maintainability. Although several techniques for code clone detection exist, many encounter challenges in effectively identifying semantic clones due to their inability to extract syntax and semantics information. Fewer techniques leverage low-level source code representations like bytecode or assembly for clone detection. This work introduces a novel code representation for identifying syntactic and semantic clones in Java source code. It integrates high-level features extracted from the Abstract Syntax Tree with low-level features derived from intermediate representations generated by static analysis tools, like the Soot framework. Leveraging this combined representation, fifteen machine-learning models are trained to effectively detect code clones. Evaluation on a large dataset demonstrates the models' efficacy in accurately identifying semantic clones. Among these classifiers, ensemble classifiers, such as the LightGBM classifier, exhibit exceptional accuracy. Linearly combining features enhances the effectiveness of the models compared to multiplication and distance combination techniques. The experimental findings indicate that the proposed method can outperform the current clone detection techniques in detecting semantic clones.
Topics: Semantics; Software; Programming Languages; Machine Learning; Algorithms
PubMed: 38728285
DOI: 10.1371/journal.pone.0302333 -
ACS Omega Apr 2024This work presented the influence of metal oxides as the support for silver-supported catalysts on the catalytic oxidation of diesel particulate matter (DPM). The...
This work presented the influence of metal oxides as the support for silver-supported catalysts on the catalytic oxidation of diesel particulate matter (DPM). The supports selected to be used in this work were CeO (reducible), ZnO (semiconductor), TiO (reducible and semiconductor), and AlO (acidic). The properties of the synthesized catalysts were investigated using XRD, TEM, H-TPR, and XPS techniques. The DPM oxidation activity was performed using the TGA method. Different states of silver (e.g., Ag° and Ag) were formed with different concentrations and affected the performance of the DPM oxidation. AgO and lattice oxygen, which were mainly generated by Ag/ZnO and Ag/CeO, were responsible for combusting the VOCs. The metallic silver (Ag°) formed primarily on Ag/AlO and Ag/TiO was the main component promoting soot combustion. Contact between the catalyst and DPM had a minor effect on VOC oxidation but significantly affected the soot oxidation activity.
PubMed: 38708233
DOI: 10.1021/acsomega.4c00218 -
Evaluation of biological markers for the risk assessment of carbon black in epidemiological studies.Frontiers in Public Health 2024Engineered nanomaterials (ENMs) have been suggested as being capable of promoting inflammation, a key component in the pathways associated with carcinogenesis,... (Review)
Review
BACKGROUND/OBJECTIVES
Engineered nanomaterials (ENMs) have been suggested as being capable of promoting inflammation, a key component in the pathways associated with carcinogenesis, cardiovascular disease, and other conditions. As a result, the risk assessment of biological markers as early-stage indicators has the potential to improve translation from experimental toxicologic findings to identifying evidence in human studies. The study aims to review the possible early biological changes in workers exposed to carbon black (CB), followed by an evidentiary quality evaluation to determine the predictive value of the biological markers.
METHODS
We conducted a literature search to identify epidemiological studies that assessed biological markers that were involved in the inflammatory process at early stages among workers with exposure to CB. We reviewed the studies with specific reference to the study design, statistical analyses, findings, and limitations.
RESULTS
We identified five Chinese studies that investigated the potential impact of exposure to CB on inflammatory markers, bronchial wall thickening, genomic instability, and lung function impairment in CB production workers. Of the five Chinese studies, four were cross-sectional; another study reported results at two-time points over six years of follow-up. The authors of all five studies concluded positive relationships between exposure and the inflammatory cytokine profiles. The weak to very weak correlations between biomarkers and early-stage endpoints were reported.
CONCLUSION
Most inflammatory markers failed to satisfy the proposed evidentiary quality criteria. The significance of the results of the reviewed studies is limited by the cross-sectional study design, inconsistency in results, uncertain clinical relevance, and high occupational exposures. Based on this review, the risk assessment relying on inflammatory markers does not seem appropriate at this time. Nevertheless, the novel research warrants further exploration in assessing exposure to ENMs and corresponding potential health risks in occupational settings.
Topics: Humans; Biomarkers; Soot; Risk Assessment; Occupational Exposure; Epidemiologic Studies; Inflammation
PubMed: 38689765
DOI: 10.3389/fpubh.2024.1367797