Gas Chromatograph-mass Spectrometer Research Articles

Revisit the benzene oxidation at elevated pressure

The benzene (A1) oxidation was examined in a jet-stirred reactor (JSR) within the temperature range of 880–1010 K at 12.0 atm under both fuel lean (Φ = 0.5) and rich (Φ = 3.0) conditions. Eighteen intermediates and products were identified and quantified by gas chromatography (GC) and gas chromatograph-mass spectrometer (GC–MS). A kinetic model comprising 280 species and 1734 reactions was developed and validated against the experimental data to investigate the benzene reactions occurring at high pressure and low temperature. According to the sensitivity analysis, A1 + OH = A1- + H2O is the most promoting reaction for fuel consumption, while A1OH + O2 = A1O + HO2 and A1OH + OH = A1O + H2O exhibited the most inhibiting effects. HO2 radicals play an important role in the initial reaction temperature of A1 high-pressure oxidation, where the reaction rate of A1OH + O2 = A1O + HO2 is particularly critical. In comparison to previous works on A1 oxidation, oxygenated polycyclic aromatic hydrocarbons (OPAHs) benzofuran (C8H6O) and dibenzofuran (C12H8O) were newly measured and analyzed in this work. As one of the most important OPAHs species, the consumption pathway of C8H6O was updated to better describe the high-pressure oxidation. The C8H6O would potentially compete with A1 for molecular oxygen via the pathway A1 → A1O → C8H6O → decomposition products, and the process of decomposition enhances the oxygen depletion. Compared with previous oxidation studies at atmospheric pressure, the A1 initial reaction temperature shifted from 1000 to 950 K, and the temperature window of fuel conversion sharply reduced from 300 K to 70 K. Additionally, the model was effectively applied to predict the oxidation of A1 in a Jet-Stirred Reactor (JSR) over a wide range of pressures, from 0.46 to 12.0 atm. Furthermore, the developed model was compared with the laminar flame velocities (LBVs, ranging from 1.0 - 10.0 atm) and the ignition delay times (IDTs, ranging from 2.4 – 9.0 atm) data in the literature, and satisfactory agreement was obtained across a broad pressure range. The newly reported data and kinetic model provide helpful in further understanding the combustion mechanisms of aromatic hydrocarbon fuels.

Fabrication and characterization of a novel multilayer heterojunction Si3N4-PbO2 nanocomposite electrode and its application on electrocatalysis degradation of sulfathiazole

To lengthen the lifetime and extend the potential commercial applications of lead dioxide electrode, herein, a novel multilayer heterojunction Ti/ SnO2-Sb2O3/ graphene oxide/ carbon nanotube/ Si3N4-PbO2 electrode (Si3N4-PbO2 electrode) was fabricated by co-electrodeposition process that doping Si3N4 nanoparticles in eletroplating solution. Various spectroscopic and microscopic techniques, including scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were employed to characterize the surface of the fabricated electrode. The EDS analysis confirmed the successful attachment of 5.49 %wt Si and 2.46 %wt N elements from Si3N4 nanoparticles onto the PbO2 surface, while the XRD results indicated a shift in the preferred orientation of PbO2 grains from β(110) to β(101). The water adsorption energy and ·OH desorption energy in the electrocatalysis process were determined to be 0.71 eV and 0.241 eV through theoretical calculating. Subsequently, the Si3N4-PbO2 electrode was employed as an anode for the electrocatalytic degradation of sulfathiazole-simulated wastewater and real sulfonamides wastewater. Under optimized conditions determined via response surface methodology (RSM), the COD degradation efficiency reached 69.37 % for sulfathiazole and 62.35 % for real sulfonamides wastewater. The final COD concentration of the real sulfonamides wastewater was reduced to 77.05 mg/L, under the national urban sewage discharge standard. Finally, the degradation mechanism and pathway of sulfathiazole has been arranged based on the electron spin resonance (ESR), cyclic voltammetry (CV), while the intermediates were detected by Gas Chromatography-Mass Spectrometer (GC-MS) and the reactive sites of sulfathiazole were predicted by using Fukui function.

Optimal Extraction Technique and Antibacterial Properties of Essential Oil Through Magnolia sieboldii K. Koch Leaves

To provide scientific support for the exploration and application of the essential oil derived through leaves of Magnolia sieboldii K. Koch, this paper explores extraction technology optimization, composition analysis, and antibacterial properties for the essential oil derived through Magnolia sieboldii K. Koch leaves. Essential oil derived through Magnolia sieboldii K. Koch leaves was extracted by adopting hydrodistillation. With single-factor test and reaction surface improvement methods, the extraction technology of essential oil derived through Magnolia sieboldii K. Koch leaves was optimized. The structure of chemicals has been explored through the use of gas chromatographmass spectrometer (GC-MS) technology. By conducting Kirby-Bauer test and applying spread plate method, the antibacterial properties for essential oil has been measured. The liquid-solid ratio was 7.15 mL/g, the dilution period was 4.00 h, and the NaCl mass percentage was 2.26% as a consequence of the response surface optimization. The rate about gathered essential oil under such circumstances was 0.31537%. By performing chemical composition analysis, 43 compounds were measured from essential oil. Thel oil was sensitive to Staphylococcus aureus, Bacillus subtilis, and Escherichia coli with inhibitory area diameters of 17.27, 10.85, and 9.56 mm, respectively. The minimum inhibitory concentration (MIC) values for the three bacteria strains were 2.5 × 10–6, 5 × 10–6, and 10 × 10–6 g/mL, respectively. The optimum extraction rate of essential oil derived through leaves of Magnolia sieboldii K. Koch by hydro distillation is 0.35%, with the cancer-fighting substance β-elemene reaching up to a maximum of 42.53%. Simultaneously, the essential oil derived through leaves of Magnolia sieboldii K. Koch exhibits notable antibacterial effect and large development potential, suggesting the comprehensive development and utilization.

Comparison of Antifungal Activity of Thymus Vulgaris Essential Oil and Triple Antibiotic Paste Against Candida Albicans Isolated from Root Canal (In Vitro Study)

Background The main objective of chemomechanical endodontic therapy is to reduce or eliminate microorganisms from the root canal system, and intracanal medications are used to accelerate the disinfection process. The aim of this study this study was to assess the antifungal activity of thymus vulgaris essential oil against C. albicans compared to that of triple antibiotic paste. Materials and methods C. albicans was isolated from patients who required endodontic treatment. Using the agar well diffusion method, the efficacy of Thymus vulgaris essential oil against C. albicans was determined at 25 mg/ml, 10 mg/ml, 8 mg/ml, 6 mg/ml, 4 mg/ml, and 2 mg/ml and compared to the triple antibiotic paste. The minimum inhibitory and fungicidal concentrations against Candida albicans were determined using the microbroth dilution method. The constituents were identified using a gas chromatography–mass spectrometer. Results Thymus vulgaris essential oil demonstrated antifungal activity against C. albicans, which appeared to increase as the extract concentration increased, and the difference between all concentrations and triple antibiotic paste was significant (p ≤ 0.01). The MIC and MFC for Thymus vulgaris essential oil were 0.015 mg/ml and 0.031 mg/ml, respectively. 53 compounds were identified by (GC-MS) analysis, which represented more than 95% of the oil composition. The main component was thymol (35.48%). Conclusion Thymus vulgaris essential oil is effective against C. albicans, suggesting that it has the potential to be applied as an intracanal medication.

Biomarkers for assessment of the polychemotherapy results in patients with adrenocortical cancer based on gas chromatography-mass spectrometry studies of urine steroid profiles

Background: The effectiveness of polychemotherapy (PCT) for adrenocortical cancer (ACC) is assessed by imaging tests with the RECIST 1.1 criteria. However, the presence of subclinical tumor foci does not allow for an objective measurement of the true tumor burden. As shown previously, postoperative assessment of the steroid metabolome by gas chromatography-mass spectrometry (GCMS) in ACC patients makes it possible to identify early signs of adrenal steroidogenesis abnormalities and of the recurrence of adrenocortical carcinoma.
 Aim: To identify biomarkers of response to PCT by GCMS study of the urine steroid profile in ACC patients after surgical resection of the tumor.
 Materials and methods: Urine steroid profiles were studied by GCMS (Shimadzu GCMS-TQ8050 gas chromatography-mass spectrometer) in 30 ACC patients (stages II, III and IV) after surgery and first line (combination of etoposide, doxorubicin and cisplatin with daily mitotane) and second line (gemcitabine combined with capecitabine and mitotane) PCT. The control group included 25 patients with hormonally inactive adenomas.
 Results: The response to PCT according to RECIST 1.1 criteria was obtained in 23 patients (Group 1, responders) and in 7 patients ACC progressed under PCT (Group 2, non-responders). In the responders, the urinary excretion of etiocholanolone, pregnanediol and pregnanetriol was lower than in the control group. The non-responders had higher urinary excretion of androgens, progestogens and tetrahydro-11-deoxycortisol (THS), compared to the responders and the control group. The patients with ACC progression under PCT had an increase in 3β,16,20-pregnenetriol (3β,16,20-dP3) levels and a decrease of the 3α,16,20-dP3/3β,16,20-dP3 ratio, compared to those in the PCT responders. The threshold values for urinary excretion of dehydroepiandrosterone (DHEA, ≤ 469 mcg/24h; AUC = 1.0), THS (≤ 223 mcg/24h; AUC = 1.0), and 3β,16,20-dP3 (≤ 130 mcg/24h; AUC = 0.986), as well as the 3α,16,20-dP3/3β,16,20-dP3 ratio (≥ 2.13; AUC = 1.0) had 100% sensitivity and specificity for the assessment of the PCT effectiveness.
 Conclusion: Different urine steroid profiles were obtained by GCMS in the ACC patients after PCT with and without treatment response. The 100% sensitivity and specificity of the threshold values for urinary excretion of DHEA, THS, 3β,16,20-dP3 and the 3α,16,20-dP3/3β,16,20-dP3 ratio for the assessment of PCT results indicate the potential to use these parameters as biomarkers of response or progression of the disease in the monitoring of PCT effects in ACC patients.

Evaluation of chemical components and quality in Xinhui Chenpi (Citrus reticulata ‘Chachi’) with two different storage times by GC–MS and UPLC

AbstractXinhui Chenpi (XHCP) is a well‐known type of Chenpi (CP) widely used as both a Chinese herb and a food ingredient. While previous studies have explored how the quality of CP changes over time, there has been limited research specifically on XHCP. This study aims to assess the chemical components and quality of XHCP based on total flavonoid content (TF), antioxidant activity (AA), and color value (CV) at two stages: freshly harvested (XHCP‐0Y) and after 3 years of storage (XHCP‐3Y). Thirty‐eight common volatile compounds were identified, and the content of 17 compounds among them, nine nonvolatile compounds, which included one alkaloid (synephrine), three phenolic acids (PA, protocatechuic acid, vanillic acid, and ferulic acid), and five flavonoids (narirutin, hesperidin, sinensetin, nobiletin, and tangeretin), were firstly detected by the newly developed gas chromatograph–mass spectrometer (GC–MS) and ultra‐performance liquid chromatography (UPLC) methods. Compared to XHCP‐0Y, the content of 17 volatile compounds and synephrine decreased in XHCP‐3Y to varying degrees, while the content of PA, five flavonoids, TF, AA, and CV increased. The reduction of dryness caused by volatile compounds and the enhancement of efficacy related to PA, flavonoids, and AA suggested improved quality of XHCP after 3 years of storage. The methods developed in this study show promise for evaluating the quality of XHCP during the aging process.

Association between full blood count and urine steroid metabolome in patients with adrenal masses

Background: Endogenous hypercortisolism of adrenal origin is commonly associated with immune suppression. However, these patients also have signs characteristic of chronic inflammatory diseases. Better understanding of the mechanisms that alter the functioning of the immune system would allow for the development of a patient-centered approach to the treatment of corticotropin-independent endogenous Cushing's syndrome (CS).
 Aim: To assess the association between full blood count and gas chromatography-mass spectrometry-based urinary steroid excretion in patients with adrenal masses depending on malignancy grade and presence of hypercortisolism.
 Materials and methods: We retrospectively analyzed data from 42 patients with adrenal masses who had not received chemotherapy. The median age of the patients was 54 [Q25; Q75: 37; 63] years, and 76% of them were female. Preoperatively, all patients had hematology tests with differential leukocyte count. Steroid metabolome was assessed with Shimadzu GCMS-TQ8050 gas chromatography-mass spectrometer.
 Results: Twelve (12) patients had adrenocortical cancer (ACC) and CS, 9 patients had ACC without CS, 11 had adrenocortical adenomas (ACA) and CS, and 10 patients had ACA without CS. ACC patients had a higher neutrophil-to-lymphocyte ratio (NLR) than those with ACA: 3.35 [2.5; 6.3] vs 1.99 [1.41; 2.65] (р = 0.001). There was a linear correlation between NLR and serum cortisol levels after the 1 mg overnight dexamethasone suppression test (r = 0.41, p = 0.01), urinary excretion of 5β-tetrahydrocortisol (5β-THF) (r = 0.71, p 0.001) and 11β-hydroxyandrosterone (11β-OH-An) (r = 0.74, p 0.001). The ACC patients without CS had lower 5β-THF urinary excretion values, compared to ACA with CS patients: 931 [616; 1610] and 3139 [1480; 4375] mcg/24h, respectively (р = 0.007). 11β-OH-An urinary excretion in ACC patients without CS was higher than in ACA patients with CS: 1170 [806; 1266] и 602 [320; 739] mcg/24h (р = 0.007). The NLR cut-off value for adrenal mass malignancy in patients with CS exceeded 2.72 (sensitivity 90.0%, specificity 80.0%), and for the patients without hypercortisolism was above 1.92 (sensitivity 71.4%, specificity 100.0%).
 Conclusion: This is the first association identification between NLR, which is the marker of systemic inflammation, inflammation, and urinary excretion of 11β-OH-An, a metabolite of 11-hydroxyandrostenedione (a member of 11-oxygenated androgen family). This extends our understanding of the impact of hormonal activity of adrenal mass cells on the immune system.

Evaluation of Pesticides and Trace Metal Contaminants in Grains, Fresh Fruits and Vegetables from Odoluwa Market Ile Oluji; Ondo State Nigeria

Vegetables, fruits and grains are sources of food rich in vitamins, minerals, and fibers and also have beneficial ant oxidative effects Pesticides and trace metals typically contaminate these food products. Pesticides and trace metals are not biodegradable and have the potential for accumulation in different body organs, leading to unwanted side effects This study investigated the concentration of pesticide residues and some selected Trace metals in Vegetables, fruits and grains from Odolua market Ile-Oluji Ondo State. Samples were collected randomly from the market, representative portion of the samples was chopped into small pieces and blended using a blender..Quantitative determination of the pesticide for Herbicides, organochlorine and organophosphate was carried out using Gas Chromatography-Mass Spectrometer after liquid-liquid extraction. Trace Metal was determined using Inductively coupled plasma - optical emission spectrometry (ICP-OES). The results reveal the presence of pesticide residues in all the samples. The mean concentration of pesticides in the samples was below the maximum residue limits (MRs) value for World health organization (WHO) while some were higher. The results also shows that all the trace metals analyzed are present in the samples except for Cadmium which is below the detection limit while Lead and Cobalt are only detected in one sample each. Some concentrations of the trace metals were below the permissible limit for WHO while others were higher than the permissible limit.

A study of pomegranate peel extract effect on corrosion inhibition performance on aluminum in HNO3 solution

Green corrosion inhibitors have an important role in reducing the corrosion rate of metals and the effects of toxic chemicals in the environment. In this study, the inhibition effect of pomegranate peel extract (PPE) with concentration of 0.5, 1, 1.5, 2, 2.5 and 3g/L on the aluminum 1050 alloy corrosion behavior in the nitric acid solution investigates using the weight loss, electrochemical techniques, scanning electron microscope (SEM), atomic force microscope (AFM), contact angle images, gas chromatography-mass spectrometer (GC-MS) analysis, fourier transform Infrared spectroscopy (FTIR) and ultraviolet radiation (UV-IR). And, the (UV-IR), (GC-MS), and FTIR results confirm the presence of many organic compounds (Containing the N, S, and O atoms), which are responsible for inhibitor performance and absorption phenomena. Meanwhile, the electrochemical impedance results (EIS) indicate that the double layer capacity decreases and the corrosion resistance (Corrosion current density (icorr) from 0.128 to 0.009mA/cm2) increases with the increase of the inhibitor concentration (The inhibition efficiency increased with increasing the inhibitor concentration from % 54.29 to the % 92.58 at (1 to 3g/L). In addition, the corrosion current density decreases with the increase of the inhibitor concentration using the potentiodynamic polarization (PDP) test. However, the corrosion rate enhances with increasing the temperature. From the other hand, quantum chemical (QC) calculation and molecular dynamics (MD) simulation perform to investigate the theory of the adsorption mechanism. According to these studies, the adsorption of PPE on the aluminum 1050 alloy surface is agreement with the langmuir isotherm and as a result it is a mixed-type inhibitor. In final the SEM and AFM results show that the corrosion rate of the aluminum 1050 alloy surface is significantly reduced after the addition of the inhibitor to the corrosive environment. Furthermore, the contact angle image shows that the inhibited aluminum surface has a hydrophobic property in an aqueous solution. And, the QC calculation and MD simulation clarify well the thin layer formation due to the good adsorption of inhibitor (PPE) on the surface of aluminum 1050 alloy in the nitric acid solution, theoretically. It is concluded that PPE will inhibit the surface of aluminum against the corrosion agents in acidic environment and can use as a green inhibitor.

A new isopropyl esterification method for quantitative profiling of short-chain fatty acids in human and cow milk by gas chromatograph-mass spectrometer

Short-chain fatty acids (SCFAs) content in milk may have been underestimated due to the neglect of the esterified SCFAs content and the lack of an accurate detection method, especially for C1:0, C2:0, and C3:0 SCFAs. In this study, an accurate gas chromatography-mass spectrometry profiling method was established for 10 SCFAs. A 2-step esterification, including alkaline saponification (60°C for 30 min) and acid-catalyzed esterification (80°C for 150 min) in water/isopropyl/hexane (1:2:1, volume ratio), was found to be the most suitable for the quantification of esterified and nonesterified SCFAs analysis. The validation results demonstrate satisfactory linearity, sensitivity, matrix effects, precision, and accuracy. The recoveries of nonesterified and esterified SCFAs ranged from 82.78% to 112.49%, respectively. Human milk is distinguished from cow milk by its higher C1:0 and C2:0 content and lower C4:0 and C6:0 content. This method successfully accomplished qualitative and quantitative estimation of all 10 SCFAs in milk, including both nonesterified and esterified SCFAs. Furthermore, whether our method is applicable for the determination of SCFAs in serum, rumen fluid, and feces remains to be explored.

Biocontrol performance of a novel Bacillus velezensis L33a on tomato gray mold and its complete genome sequence analysis

As one of the most destructive diseases, gray mold caused by Botrytis cinerea is harmful to many important economically crops including tomatoes. The use of microorganisms for biological control is considered safe and effective. Here, a newly isolated strain L33a, which showed a 75.22% inhibition ratio against B. cinerea and broad-spectrum resistance to the tested eight phytopathogenic fungi, was characterized by a series of experiments. Strain L33a was identified as Bacillus velezensis based on its biochemical, morphological, and whole-genome profiles. Microstructural analysis revealed that L33a significantly inhibited the mycelial growth of B. cinerea by compromising the integrity of the cell membrane. The acupuncture inoculation assay demonstrated that L33a significantly alleviated disease symptoms caused by gray mold in tomato fruit through downregulation of pathogenicity-related genes of B. cinerea and activation of the transcription of genes involved in the salicylic acid (SA), jasmonic acid (JA), and antioxidant pathways of the tomato fruit. Whole-genome sequencing indicated that the total size of the L33a genome was 4032063 bp, which contained 14 biosynthetic gene clusters reported to be responsible for the biosynthesis of antimicrobial substances. Forty-one compounds were identified in the volatile organic compounds of strain L33a by using Gas Chromatography-Mass Spectrometer (GC-MS) analysis. Among these, 2,3-butanediol, acetoin, 2-tridecanol, and 2-tridecanone were the dominant compounds. Our study revealed that L33a has substantial potential as an effective biocontrol agent, offering valuable insights into postharvest fruit biocontrol.

Life-cycle profiling of cuticular hydrocarbons in the cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae)

Cuticular hydrocarbons (CHCs) are the main components of the wax layer present on insects’ surface, serving as protective agents against environmental stress and/or as communication signals. It has been documented that the chemical composition of CHCs varies with species and even with developmental stage or sex of the same species. However, studies involving in a life-cycle identification of CHCs are rare. In this work, we attempted to profile the components and relative abundance of CHCs in the cotton bollworm Helicoverpa armigera at all the four developmental stages and in both sexes of pupae and adults. A total of 29 CHCs were putatively identified by gas chromatography-mass spectrometer analysis, including 14 n-alkanes, 4 methyl-branched alkenes and 11 methyl-branched alkanes, with 15 of them being detected at all the four developmental stages. Of the 29 CHCs, the straight-chain alkanes with 27, 29 and 31 carbon atoms were the major CHCs. All three classes of CHCs (n-alkanes, methyl-branched alkanes and methyl-branched alkenes) were found in both larvae and pupae, while no unsaturated hydrocarbons were observed in eggs and adults. Methyl-branched alkanes were the main component found in eggs and adults, while the composition of n-alkanes and methyl-branched alkanes in larvae and pupae varied with ages. Principal component analysis (PCA) revealed that the CHC profiles in larvae and adults changed significantly with ages, while the CHC profiles in early pupae (1-day-old) showed distinct difference from those of late pupae. Furthermore, sexual dimorphism in the CHC profile was observed in mature adults (3-day-old and 5-day-old), with male adults possessing more n-C31 and n-C33, but less 3-MeC29 than females.

Phytochemical screening, gas chromatograph/mass spectrometer (GCMS) analysis and molecular toxicological potential of Hunteria umbellata aqueous fruit extract against Staphylococcus aureus in accessory gene regulators (AGRs)

BackgroundFruits of Hunteria umbellata (HU) have been utilized in folk medicine as potent against Staphylococcus aureus (SA) infections, particularly skin and nasal related conditions. However, there is scarcity of literature concerning toxicological evaluation of graded doses of HU fruit, especially at molecular level, specifically targeting the accessory gene regulator (AGR) system to prevent abuse of doses in the treatment of bacterial infections. This research evaluated molecular toxicological property of SA exposed to varied concentrations of aqueous HU fruit extract ranging from 500 to 3.90625 µg/µL using broth microdilution method and quantification of AGR I and II genes’ expression employing two-step reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). We first identified quality and quantity of chemical compounds in aqueous fruit of HU using phytochemistry and hybrid gas chromatograph–mass spectrometer (GC–MS) technique. Additionally, preliminary bactericidal potential of HU was assessed before molecular toxicology.ResultsResults revealed six phytochemicals and twenty analytical grade compounds from a standard library were identified from chromatograms of HU fruit extract. Some main compounds detected are n-Hexadecanoic acid (25.24%), 2-Pentadecanone, 6,10,14-trimethyl (16.08%), Cuparene (16.63%), Tetradecanoic acid (6.21%) and 9-Octadecenoic acid, (E)- (5.70%). Bactericidal activity shows significant (p < 0.05) toxicity in the tested (8) concentrations of HU fruits in a dose-response relationship compared to the controls (positive and negative). The quantified expression of AGR I and II genes in SA was most significantly increased (p < 0.05) at both 250 and 500 µg/µL of HU fruit extract while least significant increase (p < 0.05) was recorded at 125 µg/µL compared to control.ConclusionsNotably, the study highlighted a potential risk of augmented bacterial infection especially with higher doses of HU extracts during boils’ treatment and other epidermal infections instigated by Staph. Expression of both AGR genes at higher doses (250 and 500 µg/µL) is indicative of further expression of several other genes responsible for virulence factors in a variety of human bacterial infections. Thus, consumption of HU fruit to treat boils and blisters should be with great caution especially at high doses.

Ozonolysis of 2-Methyl-2-pentenal: New Insights from Master Equation Modeling.

Experimental and theoretical studies were carried out to investigate the ozonolysis of trans-2-methyl-2-pentenal. The experiments were conducted in atmospheric simulation chambers coupled to a Fourier transform infrared (FTIR) spectrometer and a gas chromatograph-mass spectrometer at room temperature and atmospheric pressure in the presence of an excess of cyclohexane in dry conditions (RH < 1%). The ozonolysis reaction was investigated theoretically from the results of accurate density functional (M06-2X) and ab initio [CCSD(T)] computations, employing the AVTZ basis set. The sequence of reaction steps was established, and the system of kinetics equations was modeled using MESMER. In the first step, a primary ozonide is formed, which then decomposes along two pathways. The principal ozonolysis products are propanal, methylglyoxal, ethylformate, and a secondary ozonide. An interesting competition between sequential reaction steps and well-skipping is found, which leads to an inversion of the expected methylglyoxal/propanal product ratio at temperatures below 210 K. The mechanism of the "hot ester" reaction channel of the Criegee intermediate was revisited. The computed ozonolysis rate constant and product branching ratio are in excellent agreement with the experimental data that are also reported in the present work.

Biocontrol efficiency and potential mechanism of streptomyces distatochromogenes XT34 against postharvest anthracnose caused by colletotrichum musae on banana fruit

Banana anthracnose caused by Colletotrichum musae is a serious postharvest disease. Use of fungicides has potential adverse effects on the environment safety and human health. Application of biological control agents (BCA) is a promising strategy for managing postharvest fruit diseases. In this study, Streptomyces sp. XT34 was isolated from the banana rhizosphere soil and exhibited a strong antifungal activity against C. musae. Combining the phenotypic and whole-genomic alignment, strain XT34 was identified as Streptomyces diastatochromogenes. Strain XT34 extracts reduced the disease incidence of anthracnose and maintained the fruit quality of banana. Treatment of extracts reduced the colonization of C. musae on fruit surface. The activity inhibition of cell wall-degrading enzymes maintained the cell-wall strength of fruit. The activity increase of defense enzymes contributed to the low disease symptom. It was supported by the differentially expressed genes (DEGs) related to supramolecular fiber organization and flavonoid biosynthesis. In addition, spore germination of C. musae was effectively inhibited by extracts. The morphology of mycelia and spore become wrinkled and ruptured. The treatment of extracts increased the optical density of A260 and soluble sugar and protein contents of C. musae. The integrity of cell membrane was also destroyed, reflecting on an increase in electrical conductivity and malondialdehyde. Several metabolites were found in the genome of strain XT34 using antiSMASH. Eleven volatile compounds were identified by gas chromatography-mass spectrometer (GC-MS). Notably, strain XT34 and extracts exhibited a broad-spectrum antifungal activity against eight phytopathogenic fungi. Hence, S. diastatochromogenes XT34 provides a potential BCA to control banana anthracnose.

Experimental Study on Adsorption and Corrosion Inhibition Properties of &amp;lt;i&amp;gt;Urena lobata&amp;lt;/i&amp;gt; Leaves Extract on Mild Steel in Acidic Medium

The corrosion inhibitive effect of &amp;lt;i&amp;gt;Urena lobata&amp;lt;/i&amp;gt; leaves extract on mild steel in 1M HCl solution was investigated via gravimetric, Electrochemical and Surface analyses. Adsorption isotherms were investigated using the Langmuir and Freundlich plots. Phytochemicals of the extract were investigated using Gas Chromatography-Mass Spectrometric (GC-MS) technique. The effect of the leaves extract through immersion time, temperature and concentration on the corrosion inhibition were obtained. The results obtained showed that the increase in extract’s concentration increased the inhibition efficiency and the protection was more on the surface of the metal at lower temperature. Maximum inhibition efficiency of 95.8% was obtained at 2.5g/L extract concentration. Corrosion rate of mild steel increased with temperature increase in the acidic solution. The adsorption process reduced as temperature increased thereby indicating physisorption. The Langmuir isotherms gave the best fit indicating chemisorption. Physical adsorption was confirmed for the leaves extract from observations of inhibition efficiency with temperature, activation energy and enthalpy of adsorption values. Hence indicating that the plant extract has mixed properties. The electrochemical results confirmed the inhibitory ability of the plant extract. The inhibition efficiencies (% IE) were attributed to the phytochemical components (alkaloids, saponins, flavonoids, tannins, cynagenic glycosides) present in the extract. The extracts of &amp;lt;i&amp;gt;Urena lobata&amp;lt;/i&amp;gt; are effective corrosion inhibitors of mild steel.

Remediation of Contaminated Soil by Polycyclic Aromatic Hydrocarbons Using Composting

Polycyclic aromatic hydrocarbons (PAHs) were one of the most concerning organic and toxic pollutants in the world. Since the 20th century, there had been no improvement in resolving or reducing the discharged or released amount of PAHs into the soil or environment. Detecting PAHs (PAHs) involved collecting environmental or biological samples, extracting PAHs using specialized techniques, and analyzing them with advanced methods like gas chromatography-mass spectrometer (GC-MS) or high performance liquid chromatography (HPLC). This process was crucial for assessing contamination levels, understanding health risks, and guiding environmental safety measures. There was no full replacement with existing technology and materials that would not release the PAHs. Now, the PAHs pollutant has caused many cases related to the impact of PAHs on the environment and human health, prompting immediate action for resolution. The remediation to remove the PAHs from the contaminated soil was conducted using the composting method. The few kinds of composting methods were vermicomposting, which used earthworms to decompose PAHs in the contaminated soil, in-vessel composting that ran the aerobic process under a close air space tank, and aerated pile that implemented the aerobic process in an open air space. The bulking agent of in-vessel composting and aerated composting was the same. Actually, these three composting methods were under bioremediation to remove PAHs from contaminated soil. There were a few challenges that would be faced by the government, the people, and the research in the future. Some recommendations have been provided to face these future challenges.

Extraction of 5 benzotriazole ultraviolet filters from soil samples using natural deep eutectic solvent vortex assisted liquid–liquid microextraction combined with GC–MS

Benzotriazole (BTRs) ultraviolet filters are a class of substances found in the environment that pose potential hazards to human health and environment. Therefore, it is essential to develop techniques for determining BTRs in the environment. In this paper, a simple, green, and effective vortex assisted liquid–liquid microextraction (VALLME) was developed to determine trace BTRs in the environment, combining natural deep eutectic solvents (NADES) with Gas chromatography-mass spectrometer (GC–MS). Result parameters were optimized by single factor analysis, Factorial Multilevel Categoric Design and Central Composite Design, and optimal extraction solve (NADES) was obtained by mixing choline chloride (ChCl) and lactic acid (LA) with the ratio 1:1. After optimization, the linearity (r2 ≥ 0.9929), LODs (0.010–0.083 μg/ml), LOQs (0.033–0.276 μg/ml), and RSD (2.96–4.21 %) were verified. For the first time, a method based on the new type of NADES for the determination of BTRs ultraviolet filters in soil was propose, which could replace traditional extractants for BTRs and serve as a sustainable and environmentally friendly extraction medium for other matrices.

Targeting glutamine metabolism exhibits anti-tumor effects in thyroid cancer.

Effective treatment for patients with advanced thyroid cancer is lacking. Metabolism reprogramming is required for cancer to undergo oncogenic transformation and rapid tumorigenic growth. Glutamine is frequently used by cancer cells for active bioenergetic and biosynthetic needs. This study aims to investigate whether targeting glutamine metabolism is a promising therapeutic strategy for thyroid cancer. The expression of glutaminase (GLS) and glutamate dehydrogenase (GDH) in thyroid cancer tissues was evaluated by immunohistochemistry, and glutamine metabolism-related genes were assessed using real time-qPCR and western blotting. The effects of glutamine metabolism inhibitor 6-diazo-5-oxo-l-norleucine (DON) on thyroid cancer cells were determined by CCK-8, clone formation assay, Edu incorporation assay, flow cytometry, and Transwell assay. The mechanistic study was performed by real time-qPCR, western blotting, Seahorse assay, and gas chromatography-mass spectrometer assay. The effect of DON prodrug (JHU-083) on thyroid cancer in vivo was assessed using xenograft tumor models in BALB/c nude mice. GLS and GDH were over-expressed in thyroid cancer tissues, and GLS expression was positively associated with lymph-node metastasis and TNM stage. The growth of thyroid cancer cells was significantly inhibited when cultured in glutamine-free medium. Targeting glutamine metabolism with DON inhibited the proliferation of thyroid cancer cells. DON treatment did not promote apoptosis, but increased the proportion of cells in the S phase, accompanied by the decreased expression of cyclin-dependent kinase 2 and cyclin A. DON treatment also significantly inhibited the migration and invasion of thyroid cancer cells by reducing the expression of N-cadherin, Vimentin, matrix metalloproteinase-2, and matrix metalloproteinase-9. Non-essential amino acids, including proline, alanine, aspartate, asparagine, and glycine, were reduced in thyroid cancer cells treated with DON, which could explain the decrease of proteins involved in migration, invasion, and cell cycle. The efficacy and safety of DON prodrug (JHU-083) for thyroid cancer treatment were verified in a mouse model. In addition to suppressing the proliferation and metastasis potential of thyroid cancer in vivo, enhanced innate immune response was also observed in JHU-083-treated xenograft tumors as a result of decreased expression of cluster of differentiation 47 and programmed cell death ligand 1. Thyroid cancer exhibited enhanced glutamine metabolism, as evidenced by the glutamine dependence of thyroid cancer cells and high expression of multiple glutamine metabolism-related genes. Targeting glutamine metabolism with DON prodrug could be a promising therapeutic option for advanced thyroid cancer.

Comparative Analysis of Characteristic Volatile Compounds in Five Types of Infant Nutrition Powders by HS-GC-IMS and GC-MS.

This study employed the headspace-gas chromatography-ion migration spectrum (HS-GC-IMS) in conjunction with the gas chromatography-mass spectrometer (GC-MS) technique for the assessment of the flavor quality of complementary food powder intended for infants and young children. A total of 62 volatile compounds were identified, including aldehydes, esters, alcohols, ketones, pyrazines, and furans, among which aldehydes were the most abundant compounds. Based on the principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models, infant nutritional powder (YYB) from different manufacturers could be clearly distinguished. Among them, 2-hydroxybenzaldehyde, 1, 2-dimethoxyethane, 2-isobutyl-3-methoxypyrazine, and methyl butyrate were the four most critical differential volatiles. In addition, these differences were also manifested in changes in fatty acids. The reason for this phenomenon can be attributed to the difference in the proportion of raw materials used in nutrition powder, micronutrient content, and the packaging process. In conclusion, this study provides comprehensive information on the flavor quality of YYB, which can be used as a basis for quality control of YYB.