Mixture Of Acetone Research Articles

Limitations and characteristics of converted industrial acrylic sheet into an in vitro platform using CO2 laser

The recent US FDA Modernization Act 2.0 has intensified interest in microfluidic-based in vitro systems for preclinical research. However, the high costs of conventional microfabrication methods and commercial devices present significant barriers, particularly in developing countries. This study addresses these challenges by exploring the use of industrial-grade acrylic sheets and a conventional CO2 laser for cost-effective microfabrication. The research investigates the effects of laser parameters—specifically nozzle speed and power—on the dimensions and quality of microchannels, surface roughness, and bonding strength. Results indicate that increased nozzle speed reduces kerf width and enhances microchannel quality, whereas high laser power (∼52 watts) induces bubbling at the edges. A simple acetone and ethanol mixture was found to provide optimal bonding strength without altering the acrylic’s molecular structure. UV spectrophotometry revealed minimal changes (∼6 %) in visible light transmittance due to bonding conditions, while FTIR analysis showed no residuals that could potentially cause cytotoxicity. Despite variations in surface roughness resulting from the etching process, cell viability remained unaffected. The surfaces supported effective cell culture for lung (A549), neuron (SH-SY5Y), and liver (HepG2) cell lines. This approach presents a practical and cost-effective solution for developing in vitro platforms, making it an accessible option for research and academic applications.

Green stability-indicating RP-HPTLC technique for determining croconazole hydrochloride

Abstract The objective of the proposed investigation is the development and validation of a green stability-indicating reverse-phase high-performance thin-layer chromatographic method to determine croconazole hydrochloride (CCZ). The developing system used was an 80:20 v/v mixture of acetone and water. The measurement of CCZ was done at 198 nm. With the use of the Analytical Eco-Scale (AES), ChlorTox, and Analytical GREEnness (AGREE) tools, greenness was evaluated. The linearity was demonstrated by the present method in the 25–1,200 ng/band range. The present approach was additionally reliable, accurate, sensitive, precise, and green. An exceptional greenness profile was demonstrated by the AES, total ChlorTox, and AGREE scales, which were determined to be 89, 1.08 g, and 0.82, respectively. The greenness metrics of the present method were much better than the reported high-performance liquid chromatography approach. Under acid and oxidative degradation circumstances, CCZ was shown to be unstable, while under alkaline and thermal-stress settings, it was sufficiently stable. Furthermore, the stability-indicating component determined by analytical method identified CCZ in the presence of its degradation products. Commercial CCZ cream was found to contain 0.98% w/w of CCZ. The investigation’s results suggested that CCZ in commercially available creams might be regularly examined with the help of the recommended green technology.

Effect of Antisolvent Used to Regenerate Cellulose Treated with Ionic Liquid on Its Properties.

The solvolysis reaction with ionic liquids is one of the most frequently used methods for producing nanometer-sized cellulose. In this study, the nanocellulose was obtained by reacting microcrystalline cellulose with 1-ethyl-3-methylimidazolium acetate (EmimOAc). The aim of this research was to determine the influence of various antisolvents used in the regeneration of cellulose after treatment with ionic liquid on its properties. The following antisolvents were used in this research: acetone, acetonitrile, water, ethanol and a mixture of acetone and water in a 1:1 v/v ratio. The nanocellulose was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM) and elemental analysis (EA). The results show that the antisolvent used to regenerate cellulose after the solvolysis reaction with EmimOAc affects its properties. Water, ethanol and a mixture of acetone and water successfully removed the used ionic liquid from the cellulose structure, while acetone and acetonitrile were unable to completely remove EmimOAc from the cellulosic material. The results of the XRD analysis indicate that there is a correlation between the ionic liquid content in the regenerated cellulose and its degree of crystallinity. Among the tested solvents, water leads to the effective removal of EmimOAc from the cellulose structure, which is additionally characterized by the smallest particle size and non-formation of agglomerates.

Organophosphate Detection in Animal-Derived Foods Using a Modified Quick, Easy, Cheap, Effective, Rugged, and Safe Method with Liquid Chromatography-Mass Spectrometry.

Organophosphates are widely used in the livestock industry. In this study, we developed a method for detecting 27 organophosphate insecticides in animal-derived foods, including beef, pork, chicken, milk, and eggs, using liquid chromatography-tandem mass spectrometry. A modified QuEChERS method was optimized for sample pretreatment. A mixture of acetonitrile and acetone was used as the extraction solvent, and MgSO4 and NaCl were used as salts. Among the five different dispersive solid-phase extraction systems, MgSO4, primary secondary amines, and C18 were selected for purification because they had the highest recovery rates and least matrix effects. The matrix-dependent limit of quantitation was 0.0005-0.005 mg/kg, and the correlation coefficient of the matrix-matched calibration curve was >0.99, which was acceptable for quantifying residues below 0.01 mg/kg-the default maximum residue limit in a positive list system. The recovery efficiencies ranged from 71.9 to 110.5%, with standard deviations ranging from 0.2% to 12.5%, satisfying the SANTE guidelines. The established analytical method was used to monitor organophosphates in animal-derived foods obtained from a local market, and no pesticides were detected. With respect to industry standards, our proposed method is recommended for practical organophosphate detection in animal-derived foods.

Origin of copper dissolution under electrocatalytic reduction conditions involving amines.

Cu dissolution has been identified as the dominant process that causes cathode degradation and losses even under cathodic conditions involving methylamine. Despite extensive experimental research, our fundamental and theoretical understanding of the atomic-scale mechanism for Cu dissolution under electrochemical conditions, eventually coupled with surface restructuring processes, is limited. Here, driven by the observation that the working Cu electrode is corroded using mixtures of acetone and methylamine even under reductive potential conditions (-0.75 V vs. RHE), we employed Grand Canonical density functional theory to understand this dynamic process under potential from a microscopic perspective. We show that amine ligands in solution directly chemisorb on the electrode, coordinate with the metal center, and drive the rearrangement of the copper surface by extracting Cu as adatoms in low coordination positions, where other amine ligands can coordinate and stabilize a surface copper-ligand complex, finally forming a detached Cu-amine cationic complex in solution, even under negative potential conditions. Calculations predict that dissolution would occur for a potential of -1.1 V vs. RHE or above. Our work provides a fundamental understanding of Cu dissolution facilitated by surface restructuring in amine solutions under electroreduction conditions, which is required for the rational design of durable Cu-based cathodes for electrochemical amination or other amine involving reduction processes.

Remarkable Second Harmonic Generation Response in (C5H6NO)+(CH3SO3)−: Unraveling the Role of Hydrogen Bond in Thermal Driven Nonlinear Optical Switch

AbstractHeat‐activated second harmonic generation (SHG) switching materials are gaining interest for their ability to switch between SHG on and off states, offering potential in optoelectronic applications. The novel nonlinear optical (NLO) switch, (C5H6NO)+(CH3SO3)− (4‐hydroxypyridinium methylsulfonate, 4HPMS), is a near‐room‐temperature thermal driven material with a strong SHG response (3.3 × KDP), making it one of the most potent heat‐stimulated NLO switches. It offers excellent contrast of 13 and a high laser‐induced damage threshold (2.5 × KDP), with reversibility > 5 cycles. At 73 °C, 4HPMS transitions from the noncentrosymmetric Pna21 room temperature phase (RTP) to the centrosymmetric P21/c phase, caused by the rotation of the (C5H6NO)+ and (CH3SO3)− due to partially thermal breaking of intermolecular hydrogen bonds. The reverse phase change exhibits a large 50 °C thermal hysteresis. Density functional theory (DFT) calculations show that (C5H6NO)+ primarily dictates both the SHG coefficient (dij) and birefringence (▵n(Zeiss) = 0.216 vs ▵n(cal.) = 0.202 at 546 nm; Δn(Immersion) = 0.210 vs ▵n(cal.) = 0.198 at 589.3 nm), while the band gap (Eg) is influenced synergistically by (C5H6NO)+ and (CH3SO3)−. Additionally, 4HPMS‐RTP also exhibits mechanochromism upon grinding as well as an aggregation‐enhanced emission in a mixture of acetone and water.

Novel tributyl phosphate-based deep eutectic solvent: Application in microwave assisted extraction of carotenoids

A contribution to the use of deep eutectic solvents (DES) and microwave-assisted extraction (MAE) was made for bioactive compounds recovery, especially those with lipophilic character, from tomato and carrot samples rich in carotenoids. For the first time, a novel deep eutectic solvent was synthesized, comprising tributyl phosphate (TBP) as a hydrogen bond acceptor and acetic acid (AcOH) as a hydrogen bond donor. The total antioxidant capacity (TAC) of tomato and carrot extracts obtained by MAE, in which optimization of operational parameters and modeling were made with the use of Box-Behnken design of the response surface methodology (RSM), was evaluated using the Cupric Reducing Antioxidant Capacity (CUPRAC) method. For the highest TAC, operational parameters that best suit the MAE procedure were set at 80 °C, 35 min, and 25 mL/2.0 g. The TAC values of extracts obtained by MAE using TBP:AcOH, 1:2 (mol/mol) were examined against those of extracts acquired by classical solvent extraction using a mixture of hexane, ethanol and acetone (H:E:A, 2:1:1 (v/v/v)) mixture. TAC of extracts in DES varied between 5.10 and 0.71 lycopene equivalents (mmol LYC kg−1). The highest extraction yield comparable to conventional organic solvents was obtained with TBP:AcOH (1:2). It was observed that, in addition to lipophilic antioxidants, some hydrophilic antioxidant compounds were partially extracted with the proposed DES. Moreover, the extracted antioxidant compounds were identified and quantified by HPLC analysis. The proposed DES and MAE process will find potential application for hydrophobic antioxidant extraction from tomatoes and carrots on an industrial scale after further studies.

Droplet Velocity Measurement Of Acetone-Water Spray Using Fluorescence-Based Particle Image Velocimetry

A method for measuring the velocity of liquid droplets emanating from an effervescent injector into ambient air was experimented using a mixture of acetone and water. Conventional methods such as Laser Doppler Velocimetry and Particle Image Velocimetry, which utilise Mie-scattering, have limitations due to multiple scattering and strong surface reflections, respectively. In the current study, we demonstrate fluorescence-based particle image velocimetry, which can overcome the abovementioned difficulty. Unlike previous similar studies that used fluorescent dyes, the inherent fluorescence of acetone is utilised in our strategy. The acetone and water were mixed in different volume ratios, and the effervescent jet was produced with air. The Gas-to-Liquid ratio of 8% was considered in this study. The spray droplets were excited using the fourth harmonic of the Nd-YAG laser. Two acetone Planar Laser laser-induced fluorescence images are acquired with a CCD camera and with a 20 µs time difference. The velocity vectors are obtained based on the cross-correlation between the two images. The results showed that absorption greatly influences the estimated velocity distribution. At a low acetone concentration, the velocity distribution became uniform around the jet centre line. A high-intensity laser could improve the velocity estimate in the core of the aerated jet. The proposed method can be applied directly to ambient and pressurised conditions where wall scattering is dominant. The directional independence of the fluorescence is also an advantage in scenarios where the imaging angle is a constraint.

تحضير ودراسة اللايكوبين الطبيعي والنانوي في تثبيط نمو الخلايا السرطانية خارج الجسم الحي In vitro

The effectiveness of both natural and nano-lycopene extracted from tomato waste powder in affecting the growth of cancer cells outside the body was studied. The study included the preparation of natural lycopene extract, using the triple mixture of hexane, acetone, and ethanol in proportions 2:1:1 and drying it, then preparing the nanocomposite using the high-energy mechanical grinding technique, and its dimensions were estimated using a Scanning Electron Microscope (SEM) and which was 78nm, and the effectiveness of the two preparations was tested in Inhibition of cancer cell lines of the human mouth and skin, during three periods of time 12, 24, 72 h and at concentrations of both natural and nano-lycopene 0.0,150, 300, 600, 1200, 2400 micrograms/ml, the results of the study showed There was a significant inhibitory effect p≤0.05. for both natural and nano-lycopene in the growth of cancer cells, and nano-lycopene was significantly superior to natural lycopene for skin and mouth models, and the inhibition effect of cancer cells increased for both natural and nano-lycopene with increasing concentration and period, and the highest percentage of inhibition for natural lycopene was 71% and 79.8% While the highest percentage of inhibition for nanoscale icon was 85.2% and 93.1% at a concentration of 2400 µg/ml for 72 h and for skin and oral cancer cell lines, respectively.

Gene essentiality in the solventogenic Clostridium acetobutylicum DSM 792.

Clostridium acetobutylicum is a leading candidate to synthesize valuable compounds like three and four carbons alcohols. Its ability to convert carbohydrates into a mixture of acetone, butanol, and ethanol as well as other chemicals of interest upon genetic engineering makes it an advantageous organism for the valorization of lignocellulose-derived sugar mixtures. Since, genetic optimization depends on the fundamental insights supplied by accurate gene function assignment, gene essentiality analysis is of great interest as it can shed light on the function of many genes whose functions are still to be confirmed. The data obtained in this study will be of great value for the research community aiming to develop C. acetobutylicum as a platform organism for the production of chemicals of interest.

Remarkable Second Harmonic Generation Response in (C5H6NO)+(CH3SO3)-: Unraveling the Role of Hydrogen Bond in Thermal Driven Nonlinear Optical Switch.

Heat-activated second harmonic generation (SHG) switching materials are gaining interest for their ability to switch between SHG on and off states, offering potential in optoelectronic applications. The novel nonlinear optical (NLO) switch, (C5H6NO)+(CH3SO3)- (4-hydroxypyridinium methylsulfonate, 4HPMS), is a near-room-temperature thermal driven material with a strong SHG response (3.3 × KDP), making it one of the most potent heat-stimulated NLO switches. It offers excellent contrast of 13 and a high laser-induced damage threshold (2.5 × KDP), with reversibility > 5 cycles. At 73 °C, 4HPMS transitions from the noncentrosymmetric Pna21 room temperature phase (RTP) to the centrosymmetric P21/c phase, caused by the rotation of the (C5H6NO)+ and (CH3SO3)- due to partially thermal breaking of intermolecular hydrogen bonds. The reverse phase change exhibits a large 50 °C thermal hysteresis. Density functional theory (DFT) calculations show that (C5H6NO)+ primarily dictates both the SHG coefficient (dij) and birefringence (▵n(Zeiss) = 0.216 vs ▵n(cal.) = 0.202 at 546 nm; Δn(Immersion) = 0.210 vs ▵n(cal.) = 0.198 at 589.3 nm), while the band gap (Eg) is influenced synergistically by (C5H6NO)+ and (CH3SO3)-. Additionally, 4HPMS-RTP also exhibits mechanochromism upon grinding as well as an aggregation-enhanced emission in a mixture of acetone and water.

Pitfalls in the Detection of Volatiles Associated with Heated Tobacco and e-Vapor Products When Using PTR-TOF-MS.

We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin, acetol, glycidol, acetaldehyde, acetone, and propylene glycol. While PTR-TOF-MS offers real-time simultaneous determination, the method selectivity is limited when analyzing compounds with identical elemental compositions or when labile compounds present in the mixture produce fragments that generate overlapping ions with other matrix components. In this study, we observed significant fragmentation of glycerin, acetol, glycidol, and propylene glycol during protonation via hydronium ions (H3O+). Nevertheless, specific ions generated by glycerin (m/z 93.055) and propylene glycol (m/z 77.060) enabled their selective detection. To thoroughly investigate the selectivity of the method, various mixtures containing both isotope-labeled and unlabeled compounds were utilized. The experimental findings demonstrated that when samples contained high levels of glycerin, it was not feasible to perform time-resolved analysis in H3O+ mode for acetaldehyde, acetol, and glycidol. To overcome the observed selectivity limitations associated with the H3O+ reagent ions, alternative ionization modes were investigated. The ammonium ion mode proved appropriate for analyzing propylene glycol (m/z 94.086) and acetone (m/z 76.076) mixtures. Concerning the nitric oxide mode, specific m/z were identified for acetaldehyde (m/z 43.018), acetone (m/z 88.039), glycidol (m/z 73.028), and propylene glycol (m/z 75.044). It was concluded that considering the presence of multiple product ions and the potential influence of other compounds, it is crucial to conduct a thorough selectivity assessment when employing PTR-TOF-MS as the sole method for analyzing compounds in complex matrices of unknown composition.

EXPLORING CYTOLOGICAL ASPECTS OF SOCKET HEALING OPTIMIZATION AFTER ATYPICALREMOVAL OF THE THIRD LOWER MOLAR

This study aims to investigate the cytological characteristics of socket healing after atypical removal of the lower third molar, utilizing osteoplastic synthetic material in conjunction with platelet-rich gel and plasma enriched with thrombocyte factors, to enhance local osteogenesis. Materials and Methods For this comparative clinical study, smears of alveolar content were collected following atypical extraction of the lower third molar. Cell elements were quantified for cytological analysis. Data collection utilized a template developed in Microsoft Excel version 16.34. Statistical processing was performed using RStudio 2023.03.1 Build 446 (Posit Software, PBC). Smears were air-dried, fixed in a 1:1 mixture of alcohol and acetone for 5 minutes, stained first with May-Grünwald’s methylene blue (15 minutes), followed by Romanowsky-Giemsa’s azure-eosin stain (30 minutes). Smear images were captured with the Leica morpho densitometric complex: DM 1000 microscope, DFC-320 camera, images were obtained in jpg format at 400x magnification. Results The study encompassed 30 patients divided into control and experimental groups. Cytological analysis was conducted on the 2nd, 5th, and 10th days of post- operation. In both groups, on the 2nd day, alveolar smears showed the presence of erythrocytes (n = 6) and neutrophils (n = 2). On the 5th day, the experimental group exhibited neutrophils (n = 3) and abundant cocci microflora (n = 6). On the 10th day, epitheliocytes (n = 8) primarily indicated proliferation. Conclusions The obtained results underscore the effectiveness of employing osteoplastic synthetic material in combination with plateletrich gel and plasma enriched with thrombocyte factors for enhancing local osteogenesis following atypical removal of the third molar. This approach demonstrates significant elevation in epithelialization activity, fibroblastic activity, and other markers of the reparative process in comparison to the control group.

Understanding the dewatering of fermentation-based 1,3-propanediol with acetone before cyclohexanone synthesis

Acetone can be produced by microbial fermentation using Clostridium acetobutylicum (acetone-n-butanol-ethanol fermentation, ABE fermentation), but it provides a mixture of acetone, 1-butanol, and ethanol. N-butanol and ethanol can be used as biofuels, but high-value applications of acetone generally require upgrading. Bio-based 1,3-propanediol is more readily produced by fermentation and separated at higher titers and has been used industrially. Therefore, the coupled upgrading of the two fermentation products can provide another avenue for high-value utilization of acetone. In this paper, salting-out extraction of 1,3-propanediol with acetone was carried out, and 1,3-propanediol and acetone would spontaneously form an organic phase, thus reducing the energy consumption in the 1,3-propanediol separation process. As the double alkylation reaction of acetone with equivalent 1,3-propanediol would generate cyclohexanone, the extraction of 1,3-propanediol with acetone can provide new insight into the process intensification (removing water, salt and water concentrated in the aqueous phase) for the 1,3-propanediol separation and conversion.

Remnant polarization and structural arrangement in P(VDF-TrFE) electrospun fiber meshes affect osteogenic differentiation of human mesenchymal stromal cells

Many tissues and cells are influenced by mechano-electric stimulation, thus the application of piezoelectric materials has recently received considerable attention in tissue engineering. This report investigated electrospun fiber meshes based on poly(vinylidenefluoride-co-trifluoroethylene) [P(VDF-TrFE)] as instructive biomaterials for osteogenic differentiation of human mesenchymal stromal cells (hMSCs). The influence played by methyl ethyl ketone (MEK), used as a solvent in place of dimethylformamide (DMF)/acetone mixture, and the effect of rotating velocity of the electrospinning collector on fiber morphology, mechanical and piezoelectric properties were studied. The solvent had noticeable effects on morphology and piezoelectric properties of electrospun fibers, with MEK outperforming DMF/acetone. By increasing the collector velocity up to 4000 rpm, the fiber diameter reduced and the mutual alignment of the fibers increased, corresponding to enhanced mechanical properties and piezo-active β-phase content. However, as a consequence of the diverse mechanical properties of random and aligned fibrous architectures, which ultimately affected the piezoelectric properties, randomly-oriented fibers exhibited higher remnant piezoelectric properties (Vout and d31 piezoelectric coefficient) than aligned ones. On these scaffolds, hMSCs showed an excellent capability of early osteogenic differentiation, leading to high calcium production. Fiber surface topology, fiber mesh morphology and remnant piezoelectric properties played a determinant role on hMSC osteogenic commitment.

3D Printing of Glass Micro-Optics with Subwavelength Features on Optical Fiber Tips.

Integration of functional materials and structures on the tips of optical fibers has enabled various applications in micro-optics, such as sensing, imaging, and optical trapping. Direct laser writing is a 3D printing technology that holds promise for fabricating advanced micro-optical structures on fiber tips. To date, material selection has been limited to organic polymer-based photoresists because existing methods for 3D direct laser writing of inorganic materials involve high-temperature processing that is not compatible with optical fibers. However, organic polymers do not feature stability and transparency comparable to those of inorganic glasses. Herein, we demonstrate 3D direct laser writing of inorganic glass with a subwavelength resolution on optical fiber tips. We show two distinct printing modes that enable the printing of solid silica glass structures ("Uniform Mode") and self-organized subwavelength gratings ("Nanograting Mode"), respectively. We illustrate the utility of our approach by printing two functional devices: (1) a refractive index sensor that can measure the indices of binary mixtures of acetone and methanol at near-infrared wavelengths and (2) a compact polarization beam splitter for polarization control and beam steering in an all-in-fiber system. By combining the superior material properties of glass with the plug-and-play nature of optical fibers, this approach enables promising applications in fields such as fiber sensing, optical microelectromechanical systems (MEMS), and quantum photonics.

Enhanced Side-Illumination of Etched Polymer Optical Fiber (POF)-Incorporated Woven Polyester (PET) Fabrics

The textile industry has been weaving polymer optical fibers (POFs) into plane fabric for many years for lighting and decoration. To apply POF-incorporated fabrics in a larger field of application, it is necessary to improve the side illumination of POF-incorporated fabrics. It has been reported that the chemical etching method is one method to enhance the illumination of POFs, while there is little research related to the application of chemical etching to enhance the illumination of POF-incorporated fabrics. In this work, the end emitting POFs (EEPOFs) were used as weft yarns, and polyethylene terephthalate (PET) yarns were used as warp yarns. The POF-incorporated woven PET fabrics were successfully fabricated with a 1/3 twill structure and then treated with a mixture of acetone and methanol (volume ratio: 1:1) for 1 min. The morphology and side illumination of etched POF-incorporated PET fabrics were investigated. As a result, the acetone/methanol mixture destroyed the cladding layer of EEPOFs, and the luminance of etched POF-incorporated PET fabrics was increased by more than 50 %. Besides, acetone/methanol etching resulted in a higher side illumination attenuation behavior.

Controlled aggregation of unsymmetrical amphiphilic perylene diimide derivative into nanosheets

The self-assembly behavior of perylene diimide (PDI) derivatives has been manipulated to produce nanostructures with exceptional optoelectronic properties. The size and dimension of the aggregates determine their roles in various applications, which are determined by the structure and functionality of the PDI derivatives, including the solvent system in which self-assembly occurred. Herein, we report the synthesis of two new and distinct amphiphilic unsymmetric PDI derivatives. These PDIs contain alkyl chains of varying lengths at one of the imide positions, whereas the other imide position contains a fixed L-alanine substituent. In 90 % hexane or decalin in chloroform, these PDIs were aggregated to form ribbon-like morphologies. In contrast, in a polar solvent system comprised of mixtures of water and acetone, both PDI derivatives self-assembled differently to form distinct morphologies. As the synthesis of PDI-based two-dimensional supramolecular nanosheets has been challenging and also rarely mentioned in the literature, here, we have found that one of the PDI derivatives with long alkyl chain self-assembled to nanosheets in 90 % water/acetone solvent mixture.

PM2.5-bound polycyclic aromatic hydrocarbons (PAHs): quantification and source prediction studies in the ambient air of automobile workshop using the molecular diagnostic ratio

The presence of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere has been linked to health concerns, including cancer. Automobile workshops are significant contributors to PAH emissions due to their operations. Hence, this investigation aimed to identify and quantify the sources of PM2.5-bound PAHs in the ambient air of automobile workshops in Benin City, Nigeria, using molecular diagnostic ratios. PM2.5 samples were collected from 60 automobiles over 1 year, during the rainy (April to November) and dry (December to March) seasons of 2019. Sample collection utilized a low-volume air sampler with quartz filter paper, and extraction was performed using a 1:1 mixture of acetone and dichloromethane. The analysis involved an HP Agilent Technology 6890 Gas Chromatography (GC) system with a flame ionization detector. The annual average concentrations of PM2.5-bound PAHs in Benin City were 269.87 ± 249.32 ng/m3 (dry season) and 216.30 ± 204.89 ng/m3 (wet season). Molecular diagnostic ratios, such as Fl/(Fl + Py), An/(An + Phe), BaP/(BaP + Chry), BbF/BkF, InP/(InP + BghiP), and BaA/(BaA + Chr), aided in identifying PAH sources. Gasoline combustion, diesel combustion, traffic emissions, and emissions from automobile panel welders were found to be the primary sources of PAHs near vehicle workshops. These findings provide crucial insights for developing effective strategies to reduce emissions and protect public health in the air surrounding automobile workshops in Benin City.

Getting the phase consistent: The importance of phase description in balanced steady-state free precession MRI of multi-compartment systems.

Determine the correct mathematical phase description for balanced steady-state free precession (bSSFP) signals in multi-compartment systems. Based on published bSSFP signal models, different phase descriptions can be formulated: one predicting the presence and the other predicting the absence of destructive interference effects in multi-compartment systems. Numerical simulations of bSSFP signals of water and acetone were performed to evaluate the predictions of these different phase descriptions. For experimental validation, bSSFP profiles were measured at 3T using phase-cycled bSSFP acquisitions performed in a phantom containing mixtures of water and acetone, which replicates a system with two signal components. Localized single voxel MRS was performed at 7T to determine the relative chemical shift of the acetone-water mixtures. Based on the choice of phase description, the simulated bSSFP profiles of water-acetone mixtures varied significantly, either displaying or lacking destructive interference effects, as predicted theoretically. In phantom experiments, destructive interference was consistently observed in the measured bSSFP profiles of water-acetone mixtures, supporting the theoretical description that predicts such interference effects. The connection between the choice of phase description and predicted observation enables unambiguous experimental identification of the correct phase description for multi-compartment bSSFP profiles, which is consistent with the Bloch equations. The study emphasizes that consistent phase descriptions are crucial for accurately describing multi-compartment bSSFP signals, as incorrect phase descriptions result in erroneous predictions.