Laser-upgraded coal tar for smart pavements in road and bridge monitoring applications.
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ABSTRACT:
SUBMITTER: Huang J
PROVIDER: S-EPMC10928128 | biostudies-literature | 2024
REPOSITORIES: biostudies-literature
Publications
Laser-upgraded coal tar for smart pavements in road and bridge monitoring applications.
Huang Jincai J Zhang Man M He Haoyun H Li Qingang Q Zhao Yixin Y Tan Qiulin Q Zang Xining X
Microsystems & nanoengineering 20240311
The implementation of an intelligent road network system requires many sensors for acquiring data from roads, bridges, and vehicles, thereby enabling comprehensive monitoring and regulation of road networks. Given this large number of required sensors, the sensors must be cost-effective, dependable, and environmentally friendly. Here, we show a laser upgrading strategy for coal tar, a low-value byproduct of coal distillation, to manufacture flexible strain-gauge sensors with maximum gauge factor ...[more]
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Project description:BackgroundRefined coal tar sealant (RCTS) emulsions are used to seal the surface of asphalt pavement. Nine of the 22 polycyclic aromatic hydrocarbons (PAHs) evaluated in this study are classified as known, probable, or possible human carcinogens. Exposure assessment research for RCTS workers has not been published previously.ObjectivesThe overall objective of this study was to develop a representative occupational exposure assessment of PAH exposure for RCTS workers based on worksite surveys. The specific aims were to: 1) quantify full-shift airborne occupational exposures to PAHs among RCTS workers; 2) quantify workers' dermal exposures to PAHs; 3) quantify biomarkers of PAH exposure in workers' urine; 4) identify specific job titles associated with RCTS exposure; and 5) apply these results to a biological exposure index to assess risk of potential genotoxicity from occupational exposures.MethodsA total of twenty-one RCTS workers were recruited from three companies. Personal and area air samples were collected using a modification of NIOSH Method 5515. Dermal exposure was assessed by hand and neck wipes before and after shifts. Twenty-two PAHs were quantified via gas chromatography-mass spectrometry selected ion monitoring. Internal dose was estimated by quantifying select PAH metabolites in pre- and post-shift urine samples using on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry.ResultsPAH levels in the worker breathing zones were highest for naphthalene, acenaphthene, and phenanthrene, with geometric means of 52.1, 11.4, and 9.8 μg/m3, respectively. Hand wipe levels of phenanthrene, fluoranthene and pyrene were the highest among the 22 PAHs with geometric means of 7.9, 7.7, and 5.5 μg/cm2, respectively. Urinary PAH biomarkers for naphthalene, fluorene, phenanthrene, and pyrene were detected in all workers and were higher for post-shift samples than those collected pre-shift. Urinary concentrations of the metabolite 1-hydroxypyrene were greater than the American Conference of Governmental Industrial Hygienists (ACGIH) Biological Exposure Index (BEI) for this metabolite in 89 percent of post-shift samples collected on the final day of the work week or field survey. Statistically significances were found between concentrations of fluorene, naphthalene, and phenanthrene in the breathing zone of workers and their corresponding urinary PAH biomarkers. Workers were placed in two work place exposure groups: applicators and non-applicators. Applicators had higher total PAH concentrations in personal breathing zone (PBZ) air samples than non-applicators and were more likely to have post-shift hand wipe concentrations significantly higher than pre-shift concentrations. Concentrations of post-shift urinary biomarkers were higher, albeit not significantly, for applicators than non-applicators.ConclusionsThe exposure results from RCTS worker samples cannot be explained by proximal factors such as nearby restaurants or construction. Air and skin concentration levels were substantially higher for RCTS workers than previously published levels among asphalt workers for all PAHs. PAH profiles on skin wipes were more consistent with RCTS sealant product than air samples. Last day post-shift urinary concentrations of 1-hydroxypyrene greatly exceeded the ACGIH BEI benchmark of 2.5 μg/L in 25 of 26 samples, which suggests occupational exposure and risk of genotoxicity. When pyrene and benzo[a]pyrene were both detected, concentration ratios from personal exposure samples were used to calculate the adjusted BEI. Concentrations of 1-hydroxypyrene exceeded the adjusted BEIs for air, hand wipes, and neck wipes in most cases. These results indicate the need to increase safety controls and exposure mitigation for RCTS workers.
| S-EPMC9169065 | biostudies-literature
Project description:A strategy to implement four members of the classic coal-tar dye family, Michler's ketone, methylene blue, rhodamine B, and crystal violet, into [Pd2 L4 ] self-assemblies is introduced. Chromophores were incorporated into bis-monodentate ligands using piperazine linkers that allow to retain the auxochromic dialkyl amine functionalities required for intense colors deep in the visible spectrum. Upon palladium coordination, ligands with pyridine donors form lantern-shaped dinuclear cages while quinoline donors lead to strongly twisted [Pd2 L4 ] helicates in solution. In one case, single crystal X-ray diffraction revealed rearrangement to a [Pd3 L6 ] ring structure in the solid state. For nine examined derivatives, showing colors from yellow to deep violet, CD spectroscopy discloses different degrees of chiral induction by an enantiomerically pure guest. Ion mobility mass spectrometry allows to distinguish two binding modes. Self-assemblies based on this new ligand class promise application in chiroptical recognition, photo-redox catalysis and optical materials.
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Project description:Coal tar pitch (CTP) is a residue formed from the distillation of coal tar and is widely used as a carbonizable and graphitizable binder for many industrial applications. However, CTP is fossil-derived and has recently been classified as a "sunset" status material under REACH due to its toxicity, which makes finding a sustainable alternative vital. In this work, bio-oil was synthesized from the pyrolysis of fresh eucalyptus sawdust, from which wood tar biopitch (WTB) was subsequently produced by a second distillation process. Chemical characterization revealed the presence of higher amounts of aromatic compounds and PAHs in the industrially used CTP relative to the WTB. Sulfur is widely used as a graphitization promoter for CTP but has not yet been used for biopitch alternatives. Hence, graphite/WTB and graphite/CTP composites were fabricated with varying amounts of sulfur and were subsequently carbonized and graphitized at 850 and 2500 °C, respectively. The use of WTB as a binder led to less porous composites after carbonization/graphitization with higher levels of shrinkage than those based on CTP, whereas the carbon yield was very similar for both systems. The incorporation of sulfur was found to promote more compact structures with higher levels of graphitization, leading to improved electrical and mechanical properties, particularly for the composites based on CTP due to the higher levels of graphitization achieved relative to the WTB. The electrical and mechanical performance found for the WTB-based composites, combined with the much lower toxicity, evidences the promise of WTB as a sustainable alternative to traditional CTP binders.
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Project description:The influence of three coal tar pitches (CTPs), having softening points at 86, 94, and 103 °C, on the thermal behaviour of a defrosted high-volatile coal during co-carbonization and co-pyrolysis was studied. The following research techniques were used: X-raying of the coked charge, TG/FT-IR, ATR and UV spectroscopies, extraction, SEM, STEM, and XRD. It was determined that CTP additives change the structure of the coal plastic layer, the thickness of its zones, and the ordering degree of the structure of semi-cokes to a different extent and independently from their softening points. The softening points of CTPs do not influence the composition and yield of volatile products emitted from blends with pitch as well as the composition, structural-chemical parameters, and topological structure of material extracted from coal blends. It is suggested that such a lack of existence of any correlation between the softening points of CTPs and the degree of their influence on the thermal behaviour of coal was caused by the presence of the atoms of metals (Fe and Zn) in the CTPs. These atoms change the course of the carbonization of the CTPs themselves and their influence on organic substance of coal in blends with CTPs.
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Project description:Polytetrafluoroethylene (PTFE) has excellent physical properties and has been used in a wide range of applications in various fields. Adsorption research on PTFE is essential as primary research for the further application of PTFE. We attempted to adsorb coal tar dyes and model drugs such as lidocaine onto PTFE as a guideline to search for medicines that adsorb onto PTFE. Saturation curves were obtained after analyzing the adsorption of coal tar dyes on PTFE using the Hanes-Woolf plot. In addition, we collected multiple cases of ATR-FTIR spectral changes and/or retention depending on TPM derivatives and other adsorbates. Lidocaine matched some coal tar dye for the apparent spectral changes between the adsorbed molecules and its crystalline powder. The apparent spectral changes are blue-shifted, suggesting a hydrophobic interaction between the dyes/lidocaine and porous PTFE. This work provides a promising strategy for further application of PTFE.
| S-EPMC8979123 | biostudies-literature
Project description:Topical application of coal tar is one of the oldest therapies for atopic dermatitis (AD), a T helper 2 (Th2) lymphocyte-mediated skin disease associated with loss-of-function mutations in the skin barrier gene, filaggrin (FLG). Despite its longstanding clinical use and efficacy, the molecular mechanism of coal tar therapy is unknown. Using organotypic skin models with primary keratinocytes from AD patients and controls, we found that coal tar activated the aryl hydrocarbon receptor (AHR), resulting in induction of epidermal differentiation. AHR knockdown by siRNA completely abrogated this effect. Coal tar restored filaggrin expression in FLG-haploinsufficient keratinocytes to wild-type levels, and counteracted Th2 cytokine-mediated downregulation of skin barrier proteins. In AD patients, coal tar completely restored expression of major skin barrier proteins, including filaggrin. Using organotypic skin models stimulated with Th2 cytokines IL-4 and IL-13, we found coal tar to diminish spongiosis, apoptosis, and CCL26 expression, all AD hallmarks. Coal tar interfered with Th2 cytokine signaling via dephosphorylation of STAT6, most likely due to AHR-regulated activation of the NRF2 antioxidative stress pathway. The therapeutic effect of AHR activation herein described opens a new avenue to reconsider AHR as a pharmacological target and could lead to the development of mechanism-based drugs for AD.
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Project description:Coal tar (CT) is a commonly used therapeutic agent in psoriasis treatment. CT formulations currently in clinical use have limitations such as toxicity and skin staining properties, leading to patient nonadherence. The purpose of this study was to develop a nanoparticle (NP) formulation for CT based on biocompatible poly(lactide-co-glycolide) (PLGA). CT was entrapped in PLGA NPs by nanoprecipitation, and the resulting NPs were characterized using dynamic light scattering and high-performance liquid chromatography (HPLC) to determine the particle size and CT loading efficiency, respectively. In vitro biocompatibility of the NPs was examined in human dermal fibroblasts. Permeation, washability, and staining experiments were carried out using skin-mimetic Strat-M membranes in Franz diffusion cells. The optimal CT-loaded PLGA NPs achieved 92% loading efficiency and were 133 nm in size with a polydispersity index (PDI) of 0.10 and a zeta potential of -40 mV, promoting colloidal stability during storage. CT NPs significantly reduced the cytotoxicity of crude CT in human dermal fibroblasts, maintaining more than 75% cell viability at the highest concentration tested, whereas an equivalent concentration of CT was associated with 28% viability. Permeation studies showed that only a negligible amount of CT NPs could cross the Strat-M membrane after 24 h, with 97% of the applied dose found accumulated within the membrane. The superiority of CT NPs was further demonstrated by the notably diminished staining ability and enhanced washability compared to those of crude CT. Our findings present a promising CT nanoformulation that can overcome its limitations in the treatment of psoriasis and other skin disorders.
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Project description:Investigations of environmental microbial communities are crucial for the discovery of populations capable of degrading hazardous compounds and may lead to improved bioremediation strategies. The goal of this study was to identify microorganisms responsible for aerobic benzene degradation in coal tar-contaminated groundwater. Benzene degradation was monitored in laboratory incubations of well waters using gas chromatography mass spectrometry (GC-MS). Stable isotope probing (SIP) experiments using [13C]benzene enabled us to obtain 13C-labled community DNA. From this, 16S rRNA clone libraries identified Gammaproteobacteria and Betaproteobacteria as the active benzene-metabolizing microbial populations. Subsequent cultivation experiments yielded nine bacterial isolates that grew in the presence of benzene; five were confirmed in laboratory cultures to grow on benzene. The isolated benzene-degrading organisms were genotypically similar (>97% 16S rRNA gene nucleotide identities) to the organisms identified in SIP experiments. One isolate, Variovorax MAK3, was further investigated for the expression of a putative aromatic ring-hydroxylating dioxygenase (RHD) hypothesized to be involved in benzene degradation. Microcosm experiments using Variovorax MAK3 revealed a 10-fold increase in RHD (Vapar_5383) expression, establishing a link between this gene and benzene degradation. Furthermore, the addition of Variovorax MAK3 to microcosms prepared from site waters accelerated community benzene degradation and correspondingly increased RHD gene expression. In microcosms using uninoculated groundwater, quantitative (q)PCR assays (with 16S rRNA and RDH genes) showed that Variovorax was present and responsive to added benzene. These data demonstrate how the convergence of cultivation-dependent and -independent techniques can boost understandings of active populations and functional genes in complex benzene-degrading microbial communities. Benzene is a human carcinogen whose presence in contaminated groundwater drives environmental cleanup efforts. Although the aerobic biodegradation of benzene has long been established, knowledge of the identity of the microorganisms in complex naturally occurring microbial communities responsible for benzene biodegradation has evaded scientific inquiry for many decades. Here, we applied a molecular biology technique known as stable isotope probing (SIP) to the microbial communities residing in contaminated groundwater samples to identify the community members active in benzene biodegradation. We complemented this approach by isolating and growing in the laboratory a bacterium representative of the bacteria found using SIP. Further characterization of the isolated bacterium enabled us to track the expression of a key gene that attacks benzene both in pure cultures of the bacterium and in the naturally occurring groundwater microbial community. This work advances information regarding the documentation of microbial processes, especially the populations and genes that contribute to bioremediation.
| S-EPMC5288836 | biostudies-literature
Project description:Polycyclic aromatic hydrocarbons (PAHs) are a class of hundreds of structurally similar chemicals ubiquitously present in our environment. They are created during the incomplete combustion of organic materials, such as oil, wood, tobacco, and charbroiled meat. As such, human exposure to mixtures of PAHs can occur through consumption of PAH-containing foods and water, inhalation of polluted air, or dermal contact. Several PAHs have been classified as carcinogenic to humans or probably carcinogenic to humans by the International Agency for Research on Cancer. The mice in this study were exposed to a complex mixture of PAHs - coal tar. In the present study, we sought to determine the dose-dependent changes in gene expression upon oral exposure to this PAH mixture in the lung tissue. Adult male MutaTMMouse were exposed to three doses of the coal tar or vehicle control (olive oil) for 28 days and sacrificed three days after the final exposure.
2017-01-01 | GSE87690 | GEO
Project description:Mid-infrared spectral analysis has long been recognized as the most accurate noninvasive blood glucose measurement method, yet no practical compact mid-infrared blood glucose sensor has ever passed the accuracy benchmark set by the USA Food and Drug Administration (FDA): to substitute for the finger-pricking glucometers in the market, a new sensor must first show that 95% of their glucose measurements have errors below 15% of these glucometers. Although recent innovative exploitations of the well-established Fourier-transform infrared (FTIR) spectroscopy have reached such FDA accuracy benchmarks, an FTIR spectrometer is too bulky. The advancements of quantum cascade lasers (QCLs) can lead to FTIR spectrometers of reduced size, but compact QCL-based noninvasive blood glucose sensors are not yet available. This work reports on two compact sensor system designs, both reaching the FDA accuracy benchmark. Each design commonly comprises a mid-infrared QCL for emission, a multiple attenuation total reflection prism (MATR) for data acquisition, and a computer-controlled infrared detector for data analysis. The first design translates the comb-like signals into conventional spectra, and then data-mines the resultant spectra to yield blood glucose concentrations. When a pressure actuator is employed to press the patient's hypothenar against the MATR, the sensor accuracy is considered to reach the FDA accuracy benchmark. The second design abandons the data processing step of translating combs-to-spectra and directly data-mines the "first-hand" comb signal. Beyond increasing the measurement accuracy to the FDA accuracy benchmark, even without a pressure actuator, direct comb data-mining upgrades the sensor system with speed and data integrity, which can impact the healthcare of diabetic patients. Specifically, the sensor performance is validated with 492 glucose absorption scans in the time domain, each with 20 million datapoints measured from four subjects with glucose concentrations of 3.9-7.9 mM. The sensor data-mines 164 sets of critical singularity strengths, each comprising 4 critical singularity strengths directly from the 9840 million raw signal datapoints, and the 656 critical singularity strengths are subjected to a machine-learning regression model analysis, which yields 164 glucose concentrations. These concentrations are correlated with those measured with a standard finger-pricking glucometer. An accuracy of 99.6% is confirmed from the 164 measurements with errors not more than 15% from the reference of the standard glucometer.
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