Gas Chromatographic Analysis Research Articles

Selective Adipose Cryolysis for Reduction of Lingual Tissue in a Porcine Model.

Oropharyngeal fat volume is associated with obstructive sleep apnea (OSA) severity. Selective adipose cryolysis may produce cold-induced adipose cell death while sparing surrounding tissues. This study explored (1) similarities in tongue fat between porcine and human models and (2) the feasibility and potential reduction of lingual fat using selective adipose cryolysis. Porcine model. Preclinical research laboratory under IACUC-approved protocols. Anatomical, histological, and biochemical characterizations of tongue tissue from 6 porcine and 4 human cadaver specimens were conducted to establish comparative frameworks. Comparison of fat distribution and composition was conducted via image analysis of histological sections as well as gas chromatography analysis of fatty acid composition. Safety and efficacy of selective adipose cryolysis were evaluated in an additional 16 porcine animals using a prototype cooling system. Histological analysis examined tissue response at 3, 6, 30, and 45 d posttreatment. Comparative analysis revealed similar fat distribution and composition between human and porcine tongues. Selective adipose cryolysis induced progressive reduction in treated area tongue fat content at all timepoints, from 42% at baseline to 32% (t = 3 d) and 14% (t = 30 d), accompanied by macrophage infiltration, crown-like structure formation, and tissue remodeling. Selective adipose cryolysis holds promise as a targeted therapeutic approach for reducing lingual fat in humans. The porcine model may provide valuable insight into treatment mechanisms and support initial translational work. Further research is warranted to elucidate long-term treatment outcomes and optimize clinical implementation strategies, with the goal of improving management of OSA in humans.

Chemical Composition and Biological Activities of St John’s Wort (Hypericum perforatum L.) Essential Oil from Bulgaria

Since ancient times, essential oils obtained from various aromatic plants have been utilized as bioactive ingredients in medicines, foods and cosmetics. The present study aimed to investigate the chemical composition and biological activities of St John’s Wort (Hypericum perforatum L.) essential oil (SJW EO) from Bulgaria, which is known to possess various biological properties. Gas chromatography and mass spectrometry (GC–MS) analysis, determination of antioxidant activity (by the ABTS method), an antimicrobial activity test and an in vitro anti-inflammatory activity test were performed. The main classes of compounds identified by GC–MS analysis were monoterpenes (43.55%), followed by sesquiterpenes (36.81%) and alkanes (16.92%). The predominant chemical components of SJW EO were α-pinene (27.52%), followed by β-pinene (10.08%), β-caryophyllene (6.77%), germacrene D (6.37%) and caryophyllene oxide (4.48%). The highest antibacterial activity was observed against the Gram-negative bacteria Klebsiella pneumoniae ATCC 13883 (inhibition zone of 12.0 mm) and Pseudomonas aeruginosa ATCC 9027 (inhibition zone of 11.0 mm). SJW EO exhibited significant in vitro anti-inflammatory activity, as the results demonstrated that its anti-inflammatory effect was stronger than those of the conventional anti-inflammatory drugs Prednisolon Cortico and acetylsalicylic acid (Aspirin), which were used as controls (all in concentration of 1 mg/mL). The obtained results demonstrated that Bulgarian SJW EO can be used as an active ingredient in the composition of new products for the pharmaceutical and cosmetic industries.

Effect of Phosphorus Deprivation on Fatty Acid Synthesis in Scenedesmus subspicatus Microalgae from Rostherne Mere

Numerous studies have examined the feasibility of using microalgae as a long-term source of biofuel. This helped us to determine how different amounts of phosphorus changed the growth of lipids in Scenedesmus subspicatus, a freshwater microalga. This study examined the effects of various phosphorus concentrations on the biochemical makeup of algae, particularly the production of proteins and carbohydrates. When there was insufficient phosphorus, the investigation observed a significant increase in lipids and productivity of S. subspicatus. Additionally, gas chromatography was used to examine the fatty acid profiles of the green algae thoroughly. When Scenedesmus species were tested at different cell densities, the highest amount of chlorophyll was found to be 0.89 mg/L. The amounts of fatty acids in algae grown with 0.4 and 0.04 P of phosphorus were strongly correlated, as shown by the Pearson linear correlation coefficients. Gas chromatography analysis revealed that the major saturated fatty acids were stearic acid (C18:0) and palmitic acid (C16:0). In addition, confirming the presence of several unsaturated fatty acids (C16:3, C18:1, C18:2, and C18:3) has helped us learn more about S. subspicatus’s complex lipid profile of S. subspicatus and how well it can be used to produce biofuels.

Hydrocarbon potential, source correlation, and paleoenvironmental reconstruction of the Jurassic interval in the Zey Gawra Oilfield, Kurdistan Region, Iraq

A comprehensive geochemical analysis for the Sargelu, Naokelekan, and Najmah formations cutting rock and crude oil samples from Z1, Z3, and Z5 wells of Hawler Block, Kurdistan Region, Iraq have been studied for source rock evaluation. Depending on the total organic carbon (TOC) content from pyrolysis analyses, the Sargelu and Naokelekan formations are regarded as very good source rocks, and fair source rock for the Najmah Formation. The organic matter in the Sargelu Formation is characterized by types II and mixed II and III kerogens. However, the Naokelekan and Najmah formations are characterized by type II kerogen. The Sargelu and Naokelekan formations’ organic matters are at mature stages; hence, in the oil window, whereas Najmah Formation’s organic matter is at immature stage. Pyrolysis study shows that the Sargelu Formation is oil and gas prone, while the Najmah and Naokelekan formations are oil prone. The biomarkers and bulk properties of the selected oils from Gas Chromatography (GC) and Gas Chromatography-Mass Spectroscopy (GC/MS) analysis show that they originated by the same source rocks. The geochemical characteristics indicate a carbonate source in a reducing environment for the studied formations and oils. Based on the oleanane index, tricyclic terpane indices, C28S/C29S ratios, and gammacerane index, the relative age of the oils and cuttings of Sargelu, Naokelekan, and Najmah formations is Middle to Late Jurassic and deposited under moderate saline condition. The biomarkers parameters show evidence that molecules from the cutting rocks of the Sargelu and Naokelekan formations are related to the oils in Z1, Z3, and Z5 wells. However, they are not related to the Najmah Formation.

Features of gas chromatographic analysis of thermally unstable compounds

Confirming the stability of analytes during gas chromatographic (GC) analysis is an important criterion, especially for previously uncharacterized compounds. However, the variations of absolute peak areas at different injector temperatures usually do not allow us to reveal the thermal instability of analytes during GC analysis. Such variations may be caused by peak area known discrimination typical for using capillary columns, especially at low split injection. The thermal instability can be revealed only when using relative peak areas.The dependences of the relative peak areas of unstable analytes on the injector temperature (descending), as well as similar dependences for products of their decomposition (ascending), are characterized by the existence of two limits. Low-temperature limits correspond to the initial quantities of unstable analytes, and high-temperature limits, to their complete transformations. Such dependences can be approximated with an equation of logistic regression (synonymous: sigmoid or Boltzmann approximation).The relationships and features of gas chromatographic analysis of thermally unstable compounds are considered with products of free-radical isopropylbenzene (cumene) chlorination and with solutions of ethyl diazoacetate in different solvents as examples. The major cumene chlorination product, (1-chloro-1-methylethyl)benzene, undergoes dehydrochlorination at injector temperatures above 200 °С to form a single product, α-methylstyrene. The analysis of the ethyl diazoacetate solutions is accompanied by the formation of ethyl alkoxyacetates, products of the insertion of intermediate ethoxycarbonylcarbene into OH bonds of alcohols, if they are used as solvents. Comparing the temperatures of half-conversion of the initial ester, T(50 %), and half-formation of the products shows that they are equal to each other. This confirms both the process mechanism and the correctness of the data approximation.

Preliminary phase results of GC-MS analysis and cytotoxic activity of Argemone mexicana leaves methanol extract against MCF-7 cell lines

Argemone mexicana leaves (AML) contain a variety of bioactive components such as fatty acids, amino acids, phenolics and alkaloids, including Berberine, Isoquinoline, Scoulerine, Stylopine, Thalifone, Benzylisoquinolines, Protopine, and Tetrahydroberberine. This study aimed to examine the gas chromatography and mass spectrometry (GC-MS) analysis of AML extract and its cytotoxic activity on MCF-7 cell lines to identify an alternative source for anticancer treatment. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was utilized to assess the viability of AML extract-treated cells, while the apoptotic assay involved Acridine orange staining to determine the mode of cell death based on morphological and nuclear fragmentation. The GC-MS analysis was used to identify the biologically active compounds. The results showed that the percentage of cell viability after AML extract treatment ranged from 28.50% to 64.28% for concentrations of 1000 to 125 μg/ml (IC50 = 258.87 μg/ml). Statistical analysis revealed a significant difference in cell viability (p < 0.05). Exposure of cells to AML extract stimulated apoptosis through membrane blebbing, cell shrinkage, cytoplasm condensation, and nuclear fragmentation. Forty-one compounds were identified by GC-MS in the AML extract. Based on the peak area, some major compounds included n-Hexadecanoic acid (palmitic acid), 9,12-Octadecadienoic acid (Z, Z)-, Phytol, 9,12,15-Octadecatrienoic acid (Z, Z, Z)-, and 1-methyl piperidine. In conclusion, the bioactive compounds are apparently responsible for the cytotoxic effects of the AML extract, and the in-vitro results highlight the extract’s potential as a source of natural anticancer drugs. However, further investigation is necessary to confirm this.

Deciphering Isotopic Fine Structures of Silylated Compounds in Gas Chromatography-Vacuum Photoionization Orbitrap Mass Spectrometry of Bio-Oils.

We introduce vacuum resonance-enhanced multiphoton ionization (REMPI) with high-resolution Orbitrap Fourier transform mass spectrometry (FTMS) for analyzing silylated polar compounds. UV laser radiation at 248 nm sensitively and selectively targets aromatic constituents, while high-resolution mass spectrometry (HRMS) enables high-performance mass spectrometric detection. This workflow enhances the detection confidence of polar constituents by identifying unique isotopologue patterns, including at the isotopic fine structure (IFS) level, in analytical standards and complex bio-oils. A direct and derivatized gas chromatography (GC) procedure on a polar standard component mixture allowed us to explore the general ionization and detection characteristics of REMPI FTMS. HRMS enabled the examination of the complex isotopologue profiles, revealing distinct patterns for the CHOxSiy-class compounds. Particularly in complex mixtures, this isobaric/isonucleonic complexity exceeded the classical mass resolution capabilities of the employed Orbitrap D30 series and prompted the usage of prolonged transients via an external data acquisition system. This procedure substantially improved mass spectrometric results by recording the unreduced time-domain transient data for up to 2 s. Notably, the ability to distinguish diagnostic isotopic pairs, such as 12C/29Si vs 13C/28Si with a mass split of ∼3.79 mDa and 13C12C/28Si29Si vs 13C2/28Si2, with an approximate mass difference of ∼3.32 mDa, demonstrates a significant and expected performance improvement. Finally, we benchmark the GC HRMS methodology to identify silylated oxygenated and nitrogen-containing constituents in ultracomplex bio-oil samples. The presented approach of utilizing the silicon isotope pattern and unique isotopologue mass splits for increasing attribution confidence can be applied beyond bio-oils toward the general GC analyses of polar oxygenates.

Composition and polymerisation products influence on the viscosity of coal tar wash oil

Wash oil is a fraction obtained by the distillation of coal tar and is primarily used for the absorption of light oil from coke oven gas. During operation, the oil undergoes polymerization and loses some components, necessitating the removal of the used oil and its replacement with fresh wash oil. The rheological properties of the studied oils were determined using a Brookfield DV2T rotational controlled-shear rate rheometer. Gas chromatographic analysis, gas chromatography/mass spectrometry, and IR spectroscopy were employed to evaluate the oil’s characteristics. By adding individual components to the wash oil, it was found that these components could be categorized into three groups: viscosity enhancers, viscosity reducers, and non-polar oil substances with medium molecular weight that have no significant effect on viscosity. The addition of relatively polar components with greater molecular weight and a planar, rigid structure leads to an increase in viscosity. Conversely, the incorporation of naphthalene and its methyl homologues, which have lower molecular weights, reduces viscosity by disrupting intermolecular interactions; their lower heats of crystallization also inhibit the formation of structured order in the liquid, further contributing to the reduction in viscosity. The most substantial increase in oil viscosity was observed with the addition of indene-coumarone resins, attributed to their high molecular weight and polymer structure.

In silico molecular interaction analysis of phytochemicals extracted from Ornithogalum narbonense flowers.

This study used various assays to analyse the antioxidant activity and phenolic content of Ornithogalum narbonense flowers. The DPPH radical scavenging activity was found to have an IC50 value of 1276.00µg/mL, the iron chelating activity was 5.12mg/mL, and the total flavonoid content was 33.14mg QE/g extract ± 4.76. Gas chromatography analysis identified various bioactive compounds, with ethane, 1,1-diethoxy- being the most dominant at 52.87% of the total area. Molecular docking studies revealed that 3,5-Di-tert-butylphenol and 9-Octadecene exhibit significant binding affinity with human ferritin L chain (2FFX), suggesting their potential to influence iron chelation activity. Toxicity evaluations showed LD50 values of 800mg/kg for 3,5-Di-tert-butylphenol and 2760mg/kg for 9-Octadecene, categorising them into toxicity classes 4 and 5. Both compounds demonstrated minimal activity across various toxicity models. However, they displayed specific interaction profiles with targets such as Prostaglandin G/H Synthase 1 and Amine Oxidase A. In-silico cytotoxicity predictions highlighted the potential anticancer activity of 3,5-Di-tert-butylphenol against Hs 683 oligodendroglioma cells and 9-Octadecene against A2058 melanoma cells. These findings emphasise the anticancer potential of O. narbonense phytochemicals and the significance of molecular docking and toxicity profiling in drug discovery.

Solubilization of n-hexadecane by micellar solutions of trehalolipid - surfactants of biological origin

Objectives. To isolate biosurfactants of glycolipid nature produced by oil hydrocarbon degrading bacteria and to establish their ability to solubilize hydrophobic compounds in the case of n-hexadecane.Methods. Trehalolipids were isolated from bacteria Rhodococcus erythropolis X5 (VKM Ac-2532 D) and Rhodococcus erythropolis S67 (VKM Ac-2533 D) included in the MikroBak biopreparation for the bioremediation of oil-contaminated territories. The genome of R. erythropolis X5 is deposited in the National Center for Biotechnology Information database under GenBank accession numbers CP044283 and CP044284, BioSample – SAMN12818508, BioProject – PRJNA573614, and SRA – PRJNA573614. The content of trehalolipid biosurfactants was estimated by the amount of trehalose in aqueous solutions of biosurfactants using the phenolsulfur method. The surface tension of the obtained aqueous solutions of biosurfactants was determined by the du Noüy ring method using a Kruss K6 tensiometer (Kruss, Germany). The critical concentration of micelle formation was determined by the inflection point on the curves of surface tension dependence on the concentration of the biosurfactant solution. In order to establish the solubilizing ability of biosurfactants, the residual concentration of n-hexadecane in an aqueous sample of different concentrations was determined using a gas chromatographic method of analysis.Results. At a constant surface tension of 24.2 mN/m and 25.0 mN/m for R. erythropolis X5 and R. erythropolis S67, respectively, the critical micelle concentration for both strains was 33 mg/L (3.8 ∙ 10−5 mol/L). The solubilizing effect of Rhodococcus trehalolipid micellar solutions against hydrophobic n-hexadecane was demonstrated by gas chromatographic analysis. The solubilization process was characterized using molar solubilization capacity (Sm), molar solubilization ratio (MSR), micelle–water partition coefficient (Km), and solubilization energy 0 (ΔGS ). It was shown that the solubilization process of n-hexadecane proceeds spontaneously 0 (ΔGS = −35.5 kJ/mol) and more efficiently (Sm = 4.3 mol/mol, MSR = 4.7 mol/mol) than in comparison with other biosurfactants of glycolipid nature.Conclusions. Based on the value of the molar solubilization coefficient, it can be concluded that trehalolipids of the R. erythropolis X5 strain solubilize n-hexadecane in aqueous solutions to a greater extent than compared to other biosurfactants of a glycolipid nature, but are inferior to synthetic surfactants.

Harnessing microbial synergy: A comprehensive evaluation of consortia-mediated bioremediation strategies for petroleum refinery wastewater treatment

The growing global demand for energy has led to the expansion of oil and gas industries, putting our environment at risk of pollution. The unregulated discharge of petroleum refinery wastewater (PRW), accidental spills, and ineffective policies have led to severe contamination and increased environmental and health consequences making management and mitigation a priority for everyone. This study evaluated the performance of two biological treatment methods - free-cell microbial consortium and immobilized microbial system - in the remediation of PRW using physicochemical, 2,6-dichlorophenollindophenol (DCPIP), Gas chromatography (GC) and Fourier-transform infrared spectroscopy (FTIR) techniques. The effectiveness of the two microbial consortia in reducing concentrations of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) in the wastewater was compared to determine the most efficient method for treating PRW. The physicochemical result revealed cocktails of contaminants while Alcaligenes faecalis strain SLW6 and strain IAM 12369, and Providencia vermicola strain OP1, showed high degradative capacities. The immobilized and free-cell microbial systems significantly reduced the concentrations of PAHs, and HMs pollutants in the wastewater, with the former showing slightly better removal efficiencies for PAHs (92.97 % vs 87.34 %), heavy metals (99.17 %), and oil weight reduction (87.76 % vs 82.25 %) after the 28-day biodegradation period respectively. GC and FTIR analyses confirmed the formation of various degraded products, demonstrating the microbial consortia's effectiveness in degrading complex organic compounds. The findings highlight the potential of microbial consortia-mediated remediation as an eco-friendly and sustainable approach for treating PRW, contributing to protecting water resources and promoting sustainable practices in the petroleum industry.

Comparison of polysaccharides from stem barks and flowers of Magnolia officinalis: Compositional characterization, hypoglycemic and photoprotection activities.

The extraction of polysaccharides from stem barks and flowers of Magnolia officinalis were optimized using response surface methodology and the maximum yields were 4.12 ± 0.06 % and 5.5 ± 0.08 %, respectively. Three homogeneous polysaccharides including MOBP-I, MOBP-II and MOFP-I were further purified and their compositional characterization were compared. Molecular weights of MOBP-I, MOBP-II and MOFP-I were 5.9 × 103, 6.8 × 103 and 3.9 × 104 Da, respectively. Gas chromatography (GC) analysis suggested that MOBP-I, MOBP-II and MOFP-I were composed of rhamnose, arabinose, mannose, glucose and galactose at different ratios and exhibited different appearance and glycosidic linkages. MOFP-I but not MOBP-I and MOBP-II had three helix structures. MOBP-I, MOBP-II and MOFP-I showed significant hypoglycemic and photoprotection capacities with different efficacy. MOBP-I had greater hypoglycemic activity, as evidenced by the increased α-glucosidase inhibition activity and glucose consumption in insulin-resistant HepG2 cells. MOBP-II and MOFP-I were more powerful in reversing ultraviolet-B (UVB)-irradiated photoaging of HaCaT cells. The difference of polysaccharides compositions might explain for their bioactivity discrepancy.

Usability of volatile organic compounds from exhaled breath compared to those from ruminal fluid, serum, urine, and milk to identify diet-specific metabolite profiles in lactating dairy cows

To investigate dietary influences on the volatilome, the volatile subcategory of the metabolome, we performed a comparative untargeted volatilome analysis of exhaled breath, ruminal fluid, serum, urine, and milk from lactating Holstein cows fed different diets. Thirty-two cows (79.4 ± 31.3 d in milk [DIM], 30.6 ± 4.83 kg milk/d) were assigned to 4 diets. The experiment lasted 16 weeks. Throughout the experiment, half of the animals were fed a hay-based diet (HAY; n = 16), and the other half were fed a silage-based diet (SIL; n = 16). In experimental wk 5 to 12, half of the animals in each group received the control concentrate (CON), and the other half was fed with the CON supplemented with a blend of essential oils (EXP). We hypothesized that the basal diet and the essential oils influence the VOC profiles of the cows through potential changes in ruminal fermentation, digestion, and metabolism (hypothesis 1). Furthermore, we hypothesized that the potential effects of essential oils would have a delayed onset and a carryover effect (hypothesis 2). Every 4 experimental weeks, i.e., in W4, W8, W12 and W16, samples of exhaled breath, ruminal fluid, serum, urine, milk, and feed were collected for dynamic headspace extraction and gas chromatographic analysis of volatile organic compounds (VOC) in their gaseous phase. Milk yield, milk composition, body weight, and feed intake were recorded regularly. Linear mixed models and multivariate and univariate data analyses were performed. The total DMI and basal diet intake was similar between HAY and SIL cows. However, SIL cows consumed less of the concentrate, neutral detergent fiber, and water-soluble carbohydrates (WSC) and more starch than HAY cows. The SIL cows had a higher milk production than the HAY cows. No effect was found regarding the concentrate type on feed intake or milk production. Irrespective of diet, 2,957 VOC were detected in the gaseous phase of serum; 2,771 in exhaled breath; 1,016 in urine; 1,001 in milk; and 921 in ruminal fluid. Across the experimental wk 4, 8, 12 and 16, the basal diet altered the VOC profiles of ruminal fluid, urine, and exhaled breath but not those of serum and milk. The concentrate type affected only the VOC profiles of the exhaled breath. Most diet-influenced VOC in the affected biological matrices were identified as dietary components. The experimental week influenced the VOC profiles of all matrices, especially those of exhaled breath. The VOC profile of exhaled breath strongly correlated with that of urine, followed by that of ruminal fluid, milk, and serum. This study provides the first description of diet- and time-specific VOC profiles from the biological matrices of dairy cows. The identified discriminatory VOC seem suitable as markers to discriminate between HAY and SIL cows. Exhaled breath may be a promising, sensitive, and less invasive tool to follow diet- and time-related metabolic changes.

Chemical Kinetics Investigations of Dibutyl Ether Isomers Oxidation in a Laminar Flow Reactor.

The combustion kinetics of three symmetric diesel-boiling-range ether isomers were investigated experimentally using a plug flow reactor. The isomers were di-n-butyl ether (DNBE), diisobutyl ether (DIBE), and di-sec-butyl ether (DSBE). The flow reactor experiments employed oxygen as the oxidizer and helium as the diluent, with oxidation carried out at atmospheric and elevated pressure conditions and temperatures from 400 to 1000 at 20 K intervals. The fuel, oxidizer, and diluent flow rates were varied at different temperatures to maintain a constant initial fuel mole fraction of 1000 ppm under stoichiometric conditions and a residence time of 2 s. Reaction products were analyzed by gas chromatography (GC). Depending on the structure, ethers showed different degrees of negative temperature coefficient (NTC) behavior. Speciation results from the GC analysis were then compared to simulations using existing and newly developed chemical kinetic models. Most of the simulated product concentrations showed reasonable agreement with the experimental data. The chemical kinetic models were utilized to elucidate key features of the reactivity and NTC behavior of the different isomers. The chemical kinetic analysis indicates that the combustion behaviors of the three isomers are influenced by the key species formed at the low-temperature reaction regime. The key species identified for DNBE, DIBE, and DSBE at atmospheric pressure are n-butanal, isobutanal, and sec-butanol, respectively.

The Impact of Selected Eutectic Solvents on the Volatile Composition of Citrus lemon Essential Oil.

The development of new materials for the controlled release of molecules represents a topic of primary importance in medicine, as well as in food science. In recent years, eutectic solvents have been applied as releasing media due to their improved capacity to interact with specific molecules, offering a broad range of tunability. Nevertheless, their application in essential oil dissolution are rare and more data are needed to develop new generations of effective systems. Herein, three eutectic systems, respectively, composed of choline chloride and ethylene glycol (1:2 molar ratio), methyltriphenylphosphonium bromide and ethylene glycol (molar ratio 1:5), and choline chloride and glycerol (molar ratio 1:1.5) were tested as materials for the controlled release of an essential oil derived from Citrus lemon leaves. Through static headspace fractionation, followed by gas chromatographic analysis, the performances of the three systems were assessed. The specific composition of DESs was pivotal in determining the releasing polar molecules as aldehydes and alcohols. A sustainability ranking based on the EcoScale tool highlighted the superior characteristics of the choline chloride-glycerol DES.

Larvicidal properties of essential oils of three Artemisia species against the chemically insecticide-resistant Nile fever vector Culex pipiens (L.) (Diptera: Culicidae): In vitro and in silico studies

Abstract The objective of this study is to determine the larvicidal activity of essential oils (EOs) extracted from three plants of the genus Artemisia against the mosquito Culex pipiens (C. pipiens) using in vitro and in silico studies. A total number of 20 third- and fourth-instar larvae were exposed to various concentrations of the three plants. The LC50 and LC90 values of the tested Artemisia EOs were determined using Probit analysis. In addition, the sensitivity of C. pipiens to these EOs was determined and compared against a standard insecticide, temephos, under laboratory conditions. Furthermore, in silico assessments were carried out on the major constituents to help understand and explain the acquired in vivo results. Gas chromatography analysis identified the major compounds as d-limonene and β-pinene for Artemisia flahaultii, camphor and borneol for Artemisia. aragonensis, and artemisia ketone and caryophyllene for Artemisia annua. A. flahaultii oil showed the highest efficacy against C. pipiens larvae, followed by A. annua oil with average larvicidal activity. In contrast, A. aragonensis EO, composed of a high percentage of monoterpenes, was the least active. Docking simulation indicated that several studied ligands had promising binding scores within the receptor’s binding site compared to the reference insecticide temephos. The obtained results allow us to conclude that A. flahaultii, a species endemic to Morocco, is an excellent means of controlling C. pipiens.

Antioxidant and anticoagulant properties of myo-inositol determined in an ex vivo studies and gas chromatography analysis

Myo-inositol plays a key role in the vasculature and may be beneficial for preventing harmful environmental effects. In this study aortic rings were isolated from middle-aged (12-month-old) male Wistar rats and preincubated with myo-inositol (0.01–100 mg/L) for 2 h. A stable thromboxane A2 analog was added (0.1 nM, 2 h) to analyze vascular dysfunction. The concentration of myo-inositol in the organ baths was determined via gas chromatography. In another experiment, human blood plasma was subjected to pro-oxidant - hydrogen peroxide administration, and myo-inositol was added to analyze lipid and protein oxidation processes. The thromboplastin time, prothrombin time, and thrombin time were also studied. Myo-inositol administration protected thiol groups against oxidative stress, meanwhile decreased vascular contraction and potentiated vasodilation (concentrations 1–100 mg/L, but not ≤ 0.1 mg/L), and changed the level of 8-isoprostane (concentrations: 0.1–100 mg/L, but not 0.01 mg/L) in plasma treated with H2O2/Fe2+. A dose above 100 mg/L additionally protected lipids (measured as thiobarbituric acid reactive substances) and increased thrombin time. Moreover, significant differences in vascular relaxation were observed between the studied myo-inositol concentrations (1 vs. 10 vs. 100 mg/L), which was not detected under the 0.1 mg/L. The concentration of myo-inositol in the organ baths determined via gas chromatography revealed that this nutraceutical agent was not used by the aortic rings during the incubation period in physiological processes. A protective effect of myo-inositol against prooxidant damage to human plasma and rat thoracic arteries has been demonstrated.

Assessing the Impact of Climate Change on Methane Emissions from Rice Production Systems in Southern India

The impact of climate change on methane (CH4) emissions from rice production systems in the Coimbatore region (Tamil Nadu, India) was studied by leveraging field experiments across two main treatments and four sub-treatments in a split-plot design. Utilizing the closed-chamber method for gas collection and gas chromatography analysis, this study identified significant differences in CH4 emissions between conventional cultivation methods and the system of rice intensification (henceforth SRI). Over two growing seasons, conventional cultivation methods reported higher CH4 emissions (range: from 36.9 to 59.3 kg CH4 ha−1 season−1) compared with SRI (range: from 2.2 to 12.8 kg CH4 ha−1 season−1). Experimental data were subsequently used to guide parametrization and validation of the DeNitrification–DeComposition (DNDC) model. The validation of the model showed good agreement between the measured and modeled data, as denoted by the statistical tests performed, which included CRM (0.09), D-index (0.99), RMSE (7.16), EF (0.96), and R2 (0.92). The validated model was then used to develop future CH4 emissions projections under various shared socio-economic pathways (henceforth SSPs) for the mid- (2021–2050) and late (2051–2080) century. The analysis revealed a potential increase in CH4 emissions for the simulated scenarios, which was dependent on specific soil and irrigation management practices. Conventional cultivation produced the highest CH4 emissions, but it was shown that they could be reduced if the current practice was replaced by minimal flooding or through irrigation with alternating wetting and drying cycles. Emissions were predicted to rise until SSP 370, with a marginal increase in SSP 585 thereafter. The findings of this work underscored an urgency to develop climate-smart location-specific mitigation strategies focused on simultaneously improving current water and nutrient management practices. The use of methanotrophs to reduce CH4 production from rice systems should be considered in future work. This research also highlighted the critical interaction that exists between agricultural practices and climate change, and emphasized the need to implement adaptive crop management strategies that can sustain productivity and mitigate the environmental impacts of rice-based systems in southern India.

The effects of headspace volume reactor on the microbial community structure during fermentation processes for volatile fatty acid production.

The transition from traditional wastewater treatment plants to biorefineries represents an environmentally and economically sustainable approach to extracting valuable compounds from waste. Sewage sludge produced from wastewater treatment is incinerated or disposed of in specific landfills. Repurposing this waste material to recover valuable resources could help lower disposal costs and reduce environmental impact by producing other beneficial polymers. Microorganisms present in the sewage sludge can ferment organic pollutants, producing volatile fatty acids (VFA), precursors for biopolymers that could be used as an alternative to petroleum-derived plastics. To boost VFA production during sewage sludge fermentation, it is necessary to understand the operating microbial community and its metabolic capacities in anaerobic conditions. This study presents the influence of the headspace volume on the microbial community and the VFA production to define the best operational parameters in a 225 L pilot plant fermenter. The wasted sewage sludge was withdrawn from an oxic-settling-anaerobic plant that collected wastewater from the canteen and dormitory of the UNIPA Campus (Palermo University, Italy) and incubated using a 40% and a 60% headspace volume. The microbial community was analysed before and after the fermentation process through metataxonomic analysis, and VFA yields were determined by gas chromatography analysis. Our results showed that the 40% headspace volume induced a tenfold higher VFA production than the 60% headspace volume, modulating the microbial community's efforts to establish a VFA-producing factory. Notably, at 40% headspace, the relative abundance of bacteria, like Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi, significantly increased, as well as the relative abundance of Bacteroidetes and Verrucomicrobia decreased during the fermentation process. This result is consistent with the selection of efficient VFA-producing bacteria that lead to increased VFA yields that are not obtained at 60% headspace. Thus, reducing headspace is a promising strategy that can be implemented, even in full-scale plants, to optimise the wastewater reuse process and maximise VFA production to produce bioplastics, like polyhydroxyalkanoate, for the transition from linear wastewater treatment plants to circular biorefineries.

Metal–organic framework-based SERS chips enable in situ and sensitive detection of dissolved hydrogen sulfide in natural water: Towards a bring-back-chip mode for field analysis

Hydrogen sulfide (H2S) in natural water plays an important role in carbon and sulfur cycles in biosphere. Current detection protocol is complicated, which need to “bring back water” to lab followed by gas chromatograph analysis. In situ, field detection is still challenging. Herein, a portable, sensitive surface enhanced Raman scattering (SERS) chip was proposed for in situ H2S sampling and SERS signal stabilizing, enabling a “bring back chip” manner for lab analysis. The SERS chip was composed of single core-shell gold nanorod-ZIF-8 framework (Au NR@ZIF-8) nanoparticle. Relying on headspace adsorption, evaporated H2S was enriched in the ZIF-8 shell and then reacted with Au NR, resulting in the weakening of the Au-Br bond Raman peak (175 cm−1) and the appearance of the Au-S bond Raman peak (273 cm−1). The SERS signal reached equilibrium in 10 min. The detection range of H2S was 0.1–2000 μg/L and limit of detection was 0.098 μg/L. SERS signal was not interfered by normal volatile gases. Moreover, SERS signal of a reacted chip was stable at an ambient condition, allowing for in situ sampling and bring-back detection. The applicability of the chip was verified by dynamic H2S monitoring during artificial black-odor water evolution, and in-field quantitative analysis of H2S content in river water and sediment. Finally, the chip was sealed in a waterproof breathable membrane device, which realized the detection of vertical profiles of H2S in the river. This work provided a promising tool for field analysis of H2S in natural environments.