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In March of 2023, the first National Primary Drinking Water Standards for per- and polyfluoroalkyl substances (PFAS) were announced. The fourth Regulatory Determination that led to this development also included several other contaminants for consideration: 1,4-dioxane (dioxane), 1,2,3-trichloropropane (TCP), and strontium, which faced no determination at this time. In this study, the relative risks associated with these three contaminants and the two regulated PFAS, perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are analyzed on a subregion level, considering socioeconomic and racial factors in national exposure and risk levels for the U.S. population. Results indicate that PFOS and PFOA represent the greatest risk to the population in the subregions in which they are detected. Considering race and ethnicity, living in a majority-minority community may be a risk factor for exposure to strontium, while minority status did not increase exposure risk for dioxane, TCP, PFOS, and PFOA. Additionally, total cancer and non-cancer relative health indicator (RHI) matrices indicate that majority-minority communities face significantly greater risks from strontium exposure. Regression models also confirm results for strontium but place the risk on racial/ethnic minority populations more specifically in regions with greater Hispanic/Latino community percentages. Finally, while greater poverty in a subregion is associated with significantly higher cancer and non-cancer RHI values for dioxane, strontium, and TCP, after controlling for state-level variations, multi-level models reveal that greater poverty is associated with significantly lower risk from these three contaminants.

Grape juices and wines are rich in numerous groups of polyphenolic compounds which require a dedicated separation technique for such complex samples. LC × LC is considered the best technique for the analysis of such samples as it can achieve better resolution and higher peak capacity compared to 1D LC. The ever-growing demand for protecting the environment necessitates reducing or eliminating hazardous solvents to improve the environmental friendliness of analytical procedures. In this study, propylene carbonate was used as an eco-friendly mobile phase component in comprehensive two-dimensional liquid chromatography to analyze phenolic compounds in grape juices and a dealcoholized wine sample. Novel green RPLC × RPLC–DAD and RPLC × RPLC–MS methods were developed for the first time to identify phenolic compounds in five samples (two red grape juice samples, two white grape juice samples, and one dealcoholized wine sample). Four different RPLC × RPLC systems were developed; three systems were connected to a diode array detector (RPLC × RPLC–DAD), while the fourth system was connected to DAD and MS detectors (RPLC × RPLC–DAD–ESI–MS). Solvent X (propylene carbonate:ethanol, 60:40) was adopted as a green organic modifier in the first dimension ( 1 D) and methanol in the second dimension ( 2 D). The practical peak capacity and the surface coverage were calculated as metrics to measure the separation performance of all proposed systems. The orthogonality values for the setups ranged from 0.64 to 0.92 when calculated by the convex hull method, and from 0.54 to 0.80 when calculated by the asterisk equations method. The practical peak capacity production rate ranged from 14.58 to 22.52 peaks/min. The results revealed that the phenolic compounds were separated efficiently with good coverage of the 2D separation space and high peak capacity. A total of 70 phenolic compounds were detected based on MS data and information from the literature.

We report, to our knowledge, the first optical detection scheme for short-chained hydrocarbon isotopologues. The sensor system is based on photoacoustic spectroscopy (PAS). Two continuous wave, thermoelectrically cooled, distributed feedback interband cascade lasers (DFB-ICLs) with emission wavelengths around 3.33 and 3.38 μm, respectively, served as light sources. The investigations comprised the main stable carbon isotopologues of methane (12CH4, 13CH4), ethane (12CH3-12CH3, 13CH3-12CH3, 13CH3-13CH3), and propane (12CH3-12CH2-12CH3, 13CH3-12CH2-12CH3). They were selected because of their importance for numerous applications from climate and planetary research to natural gas exploration. Multiple measurements of single components in nitrogen and synthetic mixtures were conducted at room temperature and atmospheric pressure. Depending on the investigated hydrocarbon isotopologue, detection limits ranging from 0.043 ppmv to 3.4 ppmv were achieved. For a selective concentration determination, multivariate analysis (MVA) was applied. Partial least-squares regression (PLSR) was used to calculate concentrations from the PA spectra. The implementation of MVA has shown that the PA setup in principle works reliably and that the selective concentration determination of short-chained hydrocarbon isotopologues is possible.

Early cancer diagnosis relies heavily on finding appropriate materials to recognize relevant biomarkers. In this study, we conduct a first-principle density functional theory simulation to investigate the capability of two-dimensional polyaniline (g-C N) for detecting propane and acetaldehyde, as known lung cancer biomarkers. The energetically most favorable configurations of the adsorbed systems were determined, and the computed adsorption energy reveals the non-covalent interaction between biomarkers and g-C N monolayer. As a result, the adsorption process is reversible, which is fundamental for the long lifespan of biosensors in real applications. On the other hand, acetaldehyde physisorption on the g-C N monolayer induces a significant variation in the band gap, suggesting the possible use of g-C N as a resistance-based biosensor. Charge transfer analysis shows that both biomarkers act as electron acceptors from the host material. The capability of the g-C N monolayer to respond to these biomarkers was also investigated upon applying an external electric field. An electric field considerably enhances the interaction between gas molecules and the g-C N monolayer by increasing the adsorption energies and charge transfer values, which are more pronounced for acetaldehyde. The results also show that the g-C N monolayer energy band gap in the presence of biomarkers closes at high electric fields. These findings highlight the ability to adjust the sensing properties of the g-C N monolayer through an external electric field without requiring any structural modifications.

Concentrations and isotopic compositions of ethane and propane in cold, deeply buried sediments from the southeastern Pacific are best explained by microbial production of these gases in situ. Reduction of acetate to ethane provides one feasible mechanism. Propane is enriched in$^{13}C$relative to ethane. The amount is consistent with derivation of the third C from inorganic carbon dissolved in sedimentary pore waters. At typical sedimentary conditions, the reactions yield free energy sufficient for growth. Relationships with competing processes are governed mainly by the abundance of H₂. Production of C₂ and C₃ hydrocarbons in this way provides a sink for acetate and hydrogen but upsets the general belief that hydrocarbons larger than methane derive only from thermal degradation of fossil organic material.

•The recreational use of inhalants is a fairly widespread habit among adolescents.•Two cases of accidental death after sniffing of a mixture of propane and butane are presented.•The role of propane and butane in causing death was demonstrated with toxicological analyses.•The importance of correct sampling procedures and surveys was highlighted. The recreational use of inhalants is a fairly widespread habit among adolescents because of the ease of availability and methods of assumption. Their use is however not free of risks, both for direct toxicity on several target organs and for a mechanism of gas replacement with lack of oxygen. The first case concerns a 12-year-old boy who died suddenly after sniffing a mix of butane and propane contained in a can of air freshener. The second case concerns a 14-year-old boy who died by acute poisoning by the same mixture contained in a refill for lighters. High concentrations of the compounds were found in the tissues by analysis with gas chromatography–mass spectrometry. The compounds found in tissues and biological fluids were perfectly compatible with those contained in the containers used for the inhalation. The mechanisms of death were therefore assessed in a combination of the direct toxicity of the compound and oxygen replacement, thus highlighting the crucial help that toxicological analyses can provide in such cases.

A sensitive and specific LC–MS/MS method was developed and validated for simultaneous determination of 2-amino-2-(2-(4′-(2-propyloxazol-4-yl)-[1,1′-biphenyl]-4-yl)ethyl)propane-1,3-diol (SYL930) and its active phosphate metabolite (SYL930-P) in rat blood using SYL927, an analogue of SYL930 as the internal standard. Blood samples were prepared by a simple protein precipitation with acetonitrile. The chromatographic separation was performed on a ZorbaxSB-C18 column (3.5 μm, 2.1 × 100 mm) with a gradient mobile phase of methanol/water containing 0.1 % formic acid (v/v) at a flow rate of 0.2 mL/min. The detection was carried out on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) in multiple reactions monitoring mode (MRM). The monitored transitions were 381.2 → 364.2 for SYL930, 461.2 → 334.2 for SYL930-P, and 367.1 → 350.4 for the internal standard, respectively. Good linearity was obtained for the analytes over the range of 0.2–100 ng/mL for SYL930 and 0.5–100 ng/mL for SYL930-P. The lower limits of quantitation (LLOQs) for SYL930 and SYL930-P were 0.2 and 0.5 ng/mL, respectively. The intra-day and inter-day precisions (RSD, %) of analytes were within 9.87 %, and the accuracy (RE, %) ranged from −7.04 to 13.15 %. The mean recoveries for two compounds in rat blood were 87.9–109 %. The analytes were proved to be stable during all sample storage, preparation, and analytic procedures. The validated method was successfully applied to pharmacokinetic and PK/PD studies of SYL930 and SYL930-P in rats after oral administration of SYL930.

Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. XRD patterns of different compositions of zinc-copper ferrite, Zn(1-x)CuxFe2O4 (x=0.0, 0.25, 0.50, 0.75), revealed single phase inverse spinel ferrite in all the samples synthesized. With increasing copper concentration, the crystallite size was found to be increased from 28 nm to 47 nm. The surface morphology of all the samples studied by the Scanning Electron Microscopy there exhibits porous structure of particles throughout the samples. The pellets of the samples are prepared for LPG sensing characteristics. The sensing is carried out at different operating temperatures (200, 225, and 250°C) with the variation of LPG concentrations (0.2, 0.4, and 0.6 vol%). The maximum sensitivity of 55.33% is observed at 250°C operating for the 0.6 vol% LPG.

Piper amalago L. leaves were extracted with supercritical carbon dioxide and compressed propane under different conditions, and with chloroform by the conventional maceration method. These methods were compared for the pyrrolidine alkaloid content. Supercritical carbon dioxide (SFE-CO2) at 313 K and 12.55 MPa showed the highest selectivity for the main compound (600.53 mg/g of extract). A gradient high-performance liquid chromatography (HPLC) method was developed and validated to quantify the alkaloid N-[7-(3′,4′-methylenedioxyphenyl)-2(Z),4(Z)-heptadienoyl]pyrrolidine (1) in the extracts. The HPLC method showed linearity, precision and accuracy, allowing the quantitative analysis of the alkaloid in all the samples. All the extracts were tested against the promastigote and intracellular amastigote forms of Leishmania amazonensis. The antileishmanial activity was evaluated in terms of inhibitory concentration for 50% of protozoa (IC50). The cytotoxicity was also evaluated against J774A1 macrophages, and the cytotoxic concentrations for 50% of macrophages were obtained (CC50). The SFE-CO2 (313 K; 12.55 MPa) extract showed the highest antileishmanial activity with the following IC50 values of 16 and 7 µg/mL against the promastigotes and intracellular amastigotes forms, respectively. The extract showed low cytotoxicity with a CC50 value of 93 µg/mL.

We report three cases of sudden death due to inhalation of portable cooking stove fuel (case 1), cigarette lighter fuel (case 2), and liquefied petroleum gas (LPG) (case 3). Specimens of blood, urine, stomach contents, brain, heart, lung, liver, kidney, and fat were collected and analyzed for propylene, propane, isobutane, and n-butane by headspace gas chromatography. n-Butane was the major substance among the volatiles found in the tissues of cases 1 and 2, and propane was the major substance in case 3. A combination of the autopsy findings and the gas analysis results revealed that the cause of death was ventricular fibrillation induced by hard muscle exercise after gas inhalation in cases 1 and 2, and that the cause of death in case 3 might be hypoxia. It is possible that the victim in case 3 was under anesthetic toxicity of accumulated isobutane which is a minor component of liquefied petroleum gas.