Chemical Studies Research Articles

Analysis of fatal outcome structure in acute poisoning with hypotensive and antiarrhythmic drugs

Background. In many countries, there is an increase in the number of poisoning with antihypertensive and antiarrhythmic drugs taken either accidentally or for suicidal purposes. The mortality rate for these poisonings reaches 6.5%.The aim of the study was to analyze the causes of fatal outcomes in patients with acute poisoning with hypotensive and antiarrhythmic drugs.Material and methods. The inpatient medical records (Form No. 003/y), autopsy reports of forensic chemical and forensic histological studies of 80 people who died from acute poisoning with hypotensive and antiarrhythmic drugs at the N.V. Sklifosovsky Research Institute for Emergency Medicine for the period from 2011 to 2020 were analyzed.Results. The age of patients with acute poisoning with antihypertensive and antiarrhythmic drugs ranged from 16 to 94 years, of which 85% of patients were over 60 years old. Women made up 70%. Twenty five patients died in the toxicogenic stage of poisoning, other 55 died in the somatogenic stage. The causes of poisoning were the intake of hypotensive drugs (mainly calcium channel blockers) in 67% of cases, the intake of antiarrhythmic drugs from the group of beta-blockers in 33%. Poisoning on suicidal intent was recorded in 81.2% of cases. The main causes of death in the toxicogenic stage of poisoning were the following (listed in order of decreasing incidence): exotoxic shock, primary cardiotoxic effect, acute cardiovascular insufficiency. The main cause of patient death in the somatogenic stage was pneumonia.Conclusion. Acute poisoning with antihypertensive and antiarrhythmic drugs, in the vast majority of cases, occurs in patients over 60 years of age. Suicidal attempts make the main cause of poisoning. The main cause of death in the toxicogenic stage of poisoning is exotoxic shock, that one in the somatogenic stage is nosocomial pneumonia.

Natural sea water and artificial sea water are not equivalent in plastic leachate contamination studies

Background Plastic contamination is one of the concerns of our age. With more than 150 million tons of plastic floating in the oceans, and a further 8 million tons arriving to the water each year, in recent times the scientific community has been studying the effects these plastics have on sea life both in the field and with experimental approaches. Laboratory based studies have been using both natural sea water and artificial sea water for testing various aspects of plastic contamination, including the study of chemicals leached from the plastic particles to the water. Methods We obtained leachates of PVC plastic pre-production nurdles both in natural and artificial sea water, and determined the elements in excess from untreated water by Inductively coupled plasma – optical emission spectrometry. We then used these different leachates to assess developmental success in the tunicate Ciona intestinalis by treating fertilised eggs through their development to hatched larvae. Results Here we report that chemical analysis of PVC plastic pre-production pellet leachates shows a different composition in natural and artificial sea water. We find that the Zn leaching from the plastic particles is reduced up to five times in artificial sea water, and this can have an effect in the toxicological studies derived. Indeed, we observe different effects in the development of C. intestinalis when using leachates in natural or artificial sea water. We also observe that not all artificial sea waters are suitable for studying the development of the tunicarte C. intestinalis. Conclusions Our results show that, at least in this case, both types of water are not equivalent to produce plastic leachaetes and suggest that precaution should be taken when conclusions are derived from results obtained in artificial sea water.

Gastrodinol derivatives and prenylated flavones from the flower branch of Gastrodiaelata

Based on the research progress and traditional usage with whole herbal of the TCM "Tianma", chemical studies herein on the flower branch of Gastrodiaelata were carried out in-depth and got 13 compounds including the gastrodinols (1–4), the flavonoid morins (5–8, 11–12), together with the specialist mulberrofurans (9, 13) and gastrodiamide (10) for the first time from the species. The antibacterial and cholinesterase inhibitory activities were then evaluated and the results showed that compounds 5, 11, 12, 13 have good activity against anti-methicillin-resistant Staphylococcusaureus, and compounds 9, 13 had good acetylcholinesterase inhibitory activity. All these results provide new chemical composition for better understanding the traditional application of "Tianma" and for exploring new pharmacological ingredients.Graphical

DFT based Experimental investigations on the spectroscopic properties, molecular structure, and biological activity of a glucocorticoid steroid, Prednisolone

This study presents a comprehensive investigation into Prednisolone, a glucocorticosteroid drug, through vibrational analysis and DFT based quantum chemical calculations. Utilizing the DFT-B3LYP functional at the basis set 6-311++G(d,p), the research explores conformational and geometric aspects, harmonic vibrational wavenumbers, and FMO analysis. The phase angle of pseudo rotation is measured to predict the molecule's conformation. FT-IR and Raman spectra were analyzed and found that the lowering of symmetric stretching vibrations of O25-H53 and O24-H52 to 3470 and 3362 cm−1 respectively, is due to the presence of intra/intermolecular hydrogen bonding. Topology analysis (AIM, NCI,ELF, LOL) global chemical reactivity descriptor study, Hirshfeld surface analysis and electron excitation studies provide a detailed understanding of Prednisolone's molecular properties. AIM analysis proved the possibility of a strong hydrogen bond H53…….O24, because it has the minimum bond length of 1.9645 Å, accompanied by a maximum ρ value of 0.0255 a.u. The hydrogen bond O24…….H53 —– O25, indicated by blue RDG isosurfaces in NCI, with value of sign (λ2) ρ between -0.02 to -0.05 a.u, is predicted to be strong. Bandgap energy of the molecule calculated from HOMO-LUMO is 4.7105. This is well agreement with the results obtained from experimental UV-visible spectra. Molecular docking study, Drug likeness parameter analysis and ADMET properties helps in predicting the anti-inflammatory activity of the molecule.

Weld Chemistry and Microhardness Studies of Formulated SrO-CaF2-CaO- SiO2 Silica Based SMAW Electrode with Nickel Wire

Weld Chemistry and Microhardness Studies of Formulated SrO-CaF2-CaO- SiO2 Silica Based SMAW Electrode with Nickel Wire

Photocatalytic chloride-to-chlorine conversion by ionic iron in aqueous aerosols: a combined experimental, quantum chemical, and chemical equilibrium model study

Abstract. Prior aerosol chamber experiments show that the ligand-to-metal charge transfer absorption in iron(III) chlorides can lead to the production of chlorine (Cl2/Cl). Based on this mechanism, the photocatalytic oxidation of chloride (Cl−) in mineral dust–sea spray aerosols was recently shown to be the largest source of chlorine over the North Atlantic. However, there has not been a detailed analysis of the mechanism that includes the aqueous formation equilibria and the absorption spectra of the iron chlorides nor has there been an analysis of which iron chloride is the main chromophore. Here we present the results of experiments measuring the photolysis of FeCl3 ⋅ 6H2O in specific wavelength bands, an analysis of the absorption spectra of FeCln3-n (n=1 … 4) made using density functional theory, and the results of an aqueous-phase model that predicts the abundance of the iron chlorides with changes in pH and iron concentrations. Transition state analysis is used to determine the energy thresholds of the dissociations of the species. Based on a speciation model with conditions extending from dilute water droplets and acidic seawater droplets to brine and salty crust, as well as the absorption rates and dissociation thresholds, we find that FeCl2+ is the most important species for chlorine production for a wide range of conditions. The mechanism was found to be active in the range of 400 to 530 nm, with a maximum around 440 nm. We conclude that iron chlorides will form in atmospheric aerosols from the combination of iron(III) cations with chloride and that they will be activated by sunlight, generating chlorine (Cl2/Cl) from chloride (Cl−) in a process that is catalytic in both chlorine and iron.

Effects of Context-Based Teaching Chemistry on Students' Achievement: A Systematic Review

This systematic review aims to comprehensively analyze the effect of contextual-based teaching of Chemistry on students' academic achievement. The review includes an analysis of various scholarly articles that have examined the impact of integrating real-world contexts and applications into Chemistry instruction. A total of 10 study articles were selected for further analysis from databases such as ERIC, Scopus, and Google Scholar using a systematic literature review (SLR) method. These studies were thematically organized and reviewed. The interventional context-based (ICB) chemistry study articles employed a range of research designs, including Experimental research method with pre-test-posttest control group design, Experimental research with post-test only design, Quasi-experimental design, and Mixed-method research design, providing a comprehensive examination of the effect of the contextual-based teaching of Chemistry on students' academic achievement. Data analysis methods were utilized, including the independent t-test, one-way t-test, one-way ANOVA or ANOCOA, and MANOVA, to compare means between groups or against specified values. The results of the analysis indicate that context-based chemistry teaching has a positive effect on students' academic achievement. This finding has significant implications for educators, curriculum developers, and policymakers, as it can inform the design of effective Chemistry instruction that enhances students' academic performance. In conclusion, this review highlights the positive impact of contextual-based teaching of Chemistry on student achievement. The findings underscore the importance of integrating real-world contexts and applications into Chemistry instruction. This has implications for educators and policymakers in designing effective teaching strategies to improve students' academic performance in Chemistry. Additionally, the review suggests avenues for future research in this area.

Mitigating Paleocene age Ranikot shale formation swelling characteristics using carbon supported anatase-titanium dioxide (MWCNT/TiO2, GO/TiO2 and AC/TiO2) nanomaterial water-based mud—chemical and rock interaction study

Mitigating Paleocene age Ranikot shale formation swelling characteristics using carbon supported anatase-titanium dioxide (MWCNT/TiO2, GO/TiO2 and AC/TiO2) nanomaterial water-based mud—chemical and rock interaction study

Ethnobotanical Knowledge, Nutritional Composition, and Aroma Profile of Vicia kulingiana Bailey: An Underutilized Wild Vegetable Endemic to China.

Vicia kulingiana, an endemic species, serves as a wild and underutilized vegetable traditionally consumed in China. However, ethnobotanical and chemical studies of this species are not available. This study analyzed its associated ethnobotanical knowledge, nutritional composition and aroma profile. Ethnobotanical surveys revealed its diverse traditional uses, especially as a nutritious vegetable. Further analysis showed V. kulingiana leaves to be high in protein, minerals, vitamin E, and dietary fiber. In total, 165 volatile compounds, such as terpenoids, alcohols, and ketones, were identified. Among them, β-ionone is the most abundant compound with a relative percentage of 8.24%, followed by 2,2,4,6,6-pentamethylheptane (3.2%), 3-(4-methyl-3-pentenyl)furan (2.37%), and linalool (1.68%). Results supported the traditional uses of V. kulingiana's and highlighted its potential as a valuable food source, encouraging further research on its food applications. The documentation of ethnobotanical knowledge contributes to the conservation of this heritage.

Probing molecular interactions of an anti-epileptic drug, sodium valproate in aqueous MgCl2 solutions

Study of the physicochemical properties of anti-epileptic drugs in the presence of cosolutes in aqueous solutions has been a subject of interest of researchers because of their interaction with biological membranes to employ their effect. Such properties provide complete information regarding solute-solute and solute-solvent type interactions. As electrolytes are essential components of biological systems, therefore the study of drug-electrolyte chemistry is important to understand the mechanism of drug action at the molecular level and hence useful in drug design and development processes. Therefore, in the current report, the density and sound velocity of an anti-epileptic drug sodium valproate (SV) in aqueous and in aqueous solutions of an electrolyte viz. MgCl2 (mB = 0.024, 0.047, 0.070 mol kg−1) at different temperatures (288.15, 298.15, 308.15, and 318.15 K) and at a pressure of 0.101 MPa were measured along with 1H NMR spectroscopy. Various volumetric and acoustical parameters such as apparent molar volume (Vφ) and isentropic compressibility (Kφ) of the solute, apparent molar volume (Vφ°) and isentropic compressibility (Kφ°) of solute at infinite dilution, apparent molar expansibility (Eφ°) and their double derivatives (∂2Vφ°/∂T2)P, transfer volumes (∆trVφ°), hydration number (nH), acoustic impedance (Z), intermolecular free length (Lf), Wada's constant (W) and Rao's constant (R) were calculated from density and sound velocity data. The variation in all these parameters with cosolute concentration indicates the existence of hydrophilic/ionic-ionic interactions at lower concentrations but hydrophobic-ionic interactions at higher concentrations of MgCl2. The 1H NMR spectroscopic results also support the existence of hydrophobic-ionic interactions at higher concentrations of MgCl2. The decrease in electrostriction but increase in hydrophobic hydration of solute molecules has also been seen with rise in temperature.

Ultrasensitive Detection and In-Depth Chemical Mechanism Study Toward Ethanol Vapor for LaCoO3/SnO2 Nanoflower

Ultrasensitive Detection and In-Depth Chemical Mechanism Study Toward Ethanol Vapor for LaCoO₃/SnO₂ Nanoflower

Investigation on the chemical properties of some pomegranate cultivars (Punica granatum L.) grown in the Messaad Algerian arid region under drip irrigation

In Messaad a city, of Algeria central region, under arid climate, pomegranate (Punica granatum L.) is one of the main fruit crops in agricultural systems after apricot. To examine the ability of transformation and direct consumption, a chemical analysis study of pomegranate juice was conducted on fruits of three pomegranate cultivars: Khadraye KH1, Hamraye HM1, Senin Alouj SL1 from the drip-irrigated Messaad orchards. A study of chemical properties such as pH, titratable acidity TS, total solids TSS, crude fibers CF of pomegranate seed juices was carried out from the fruits of three cultivars. Descriptive statistics, analyze of variance and Principal Component Analysis based on quantitative parameters are used. The cultivars Senin Aloudj SL1 and Khadraye KH1 of Messaad are characterized as sweet with respectively 1.80 and 1.84% of crude fiber content. The cultivar Hamraye HM1 is qualified sour-sweet to sweet with 2.10% crude fiber rate. The SL1 and KH1 are suitable for the consumption in fresh and can be object of food transformation to which is added the therapeutic and medicinal interest that confers the pomegranate tree whereas the HM1 apart from its consumption can be used as excellence to food transformation in various products. The findings presented in this work justify the interest of germplasm variability not only for it fresh consumption and processing, but also in the broad sense of valorization and preserving phytogenetic resources for agriculture and food locally threatened.

Revalorization of Yerba Mate Residues: Biopolymers-Based Films of Dual Wettability as Potential Mulching Materials.

Biodegradable mulching films are a very attractive solution to agronomical practices intended to achieve more successful crop results. And, in this context, the employment of agricultural and industrial food residues as starting material for their production is an alternative with economic and environmental advantages. This work reports the preparation of bilayer films having two different wettability characteristics from three bio-derived biopolymers: TEMPO-oxidized cellulose nanofibers isolated from infused Yerba Mate residues, Chitosan and Polylactic acid. The infused Yerba Mate residues, the isolated and oxidized cellulose nanofibers, and the films were characterized. Nanofibrillation yield, optical transmittance, cationic demand, carboxyl content, intrinsic viscosity, degree of polymerization, specific surface area and length were studied for the (ligno)cellulose nanofibers. Textural and chemical analysis, thermal and mechanical properties studies, as well as water and light interactions were included in the characterization of the films. The bilayer films are promising materials to be used as mulching films.

Absorption of volatile organic compounds (VOCs) by polymer tubing: implications for indoor air and use as a simple gas-phase volatility separation technique

Abstract. Previous studies have demonstrated volatility-dependent absorption of gas-phase volatile organic compounds (VOCs) to Teflon and other polymers. Polymer–VOC interactions are relevant for atmospheric chemistry sampling, as gas–wall partitioning in polymer tubing can cause delays and biases during measurements. They are also relevant to the study of indoor chemistry, where polymer-based materials are abundant (e.g., carpets and paints). In this work, we quantify the absorptive capacities of multiple tubing materials, including four nonconductive polymers (important for gas sampling and indoor air quality), four electrically conductive polymers and two commercial steel coatings (for gas and particle sampling). We compare their performance to previously characterized materials. To quantify the absorptive capacities, we expose the tubing to a series of ketones in the volatility range 104–109 µg m−3 and monitor transmission. For slow-diffusion polymers (e.g., perfluoroalkoxy alkane (PFA) Teflon and nylon), absorption is limited to a thin surface layer, and a single-layer absorption model can fit the data well. For fast-diffusion polymers (e.g., polyethylene and conductive silicone), a larger depth of the polymer is available for diffusion, and a multilayer absorption model is needed. The multilayer model allows fitting solid-phase diffusion coefficients for different materials, which range from 4×10-9 to 4×10-7 cm2 s−1. These diffusion coefficients are ∼ 8 orders of magnitude larger than literature values for fluorinated ethylene propylene (FEP) Teflon film. This enormous difference explains the differences in VOC absorption measured here. We fit an equivalent absorptive mass (CW, µg m−3) for each absorptive material. We found PFA to be the least absorptive, with CW ∼ 105 µg m−3, and conductive silicone to be the most absorptive, with CW ∼ 1013 µg m−3. PFA transmits VOCs easily and intermediate-volatility species (IVOCs) with quantifiable delays. In contrast, conductive silicone tubing transmits only the most volatile VOCs, denuding all lower-volatility species. Semi-volatile species (SVOCs) are very difficult to sample quantitatively through any tubing material. We demonstrate a system combining several slow- and fast-diffusion tubing materials that can be used to separate a mixture of VOCs into volatility classes. New conductive silicone tubing contaminated the gas stream with siloxanes, but this effect was reduced 10 000-fold for aged tubing, while maintaining the same absorptive properties. SilcoNert (tested in this work) and Silonite (tested in previous work) steel coatings showed gas transmission that was almost as good as PFA, but since they undergo adsorption, their delay times may be humidity- and concentration-dependent.

A spectrophotometric determination and the quantum chemical investigation of Pd(II)-3-hydroxy-2-(4-methoxyphenyl)-4-oxo-4H-1-benzopyran complex

An analytical approach has been instigated for spectrophotometric inquisition of trace amounts of palladium in its bivalent oxidation state employing a novel 1-benzopyran derivative viz. A 1:2 [Pd(II):HMPB] light yellow complex is formed by a spontaneous interaction between Pd(II) and HMPB. The complex is quantitatively extracted from a weakly basic medium into dichloromethane absorbing prevalently and consistently at 405-425 nm. The method coheres to linearity up to 1.5 µg mL-1 of palladium(II). Analytical parameters such as the molar absorption coefficient (ε=3.011 × 104 L mol-1 cm-1), Sandell's sensitivity [0.0035 µg Pd(II) cm-2], % RSD (0.62%) and the limit of detection [0.0147 µg Pd(II) mL-1] indicate that the study satisfies all the criteria for good sensitivity, precision and accuracy. In addition, intervention with regard to numerous anions/complexing agents and cations of primary analytical importance has been performed to assess the method's flexibility and usefulness. The results show that the majority of them do not cause any interference during determination. To better understand chemistry of the prepared complex, spectroscopic quantum chemical studies including DFT and MEP mapping based on examination of the electronic characteristics of the complex in its most stable least energy conformation are used.
 KEY WORDS: Palladium, 3-Hydroxy-2-(4-methoxyphenyl)-4-oxo-4H-1-benzopyran, Extractive spectrophotometric determination, DFT, MEP, Docking
 Bull. Chem. Soc. Ethiop. 2024, 38(3), 591-603. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i3.4

Flavonoid glycosides from the leaves of Michelia champaca

Michelia champaca L. (Magnoliaceae) was cultivated in large scale for flowers as cosmetic raw materials, whereas the value of its leaves remains to be discovered. Our chemical study on the leaves yielded four new flavonol diglycosides, champaflavosides A–D (1–4), together with twenty-three known flavonoid glycosides (5–27). Their structures were determined by spectroscopic and chemical methods. Compounds 5–21 and 23–27 were not previously reported from the genus Michelia, and kaempferol 3-O-rutinoside (22) was obtained from this species for the first time. All the compounds were evaluated for antioxidant activity by four in vitro assays. Compounds 3–12 and 20 showed more potent 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity than l-ascorbic acid (l-AA). Compounds 2–23, 25, and 27 exhibited 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical cation scavenging activity superior to l-AA. The ferric reducing antioxidant powers (FRAP) of compounds 2–13, 17, and 19 were higher than l-AA. Further, eighteen compounds demonstrated cellular reactive oxygen species (ROS) scavenging activity, of which champaflavoside D (4), rhamnetin 3-O-neohesperidoside (8), quercetin 3-O-(6-O-E-p-coumaroyl)-neohesperidoside (9), and liquiritin (27) were more potent than curcumin. The results revealed that the renewable leaves of M. champaca are a rich source of flavonoids and antioxidants.

Rare earth element systematics of chimney anhydrite from seafloor hydrothermal vents

Comparative studies of sulphide chemistry have been conducted over the past few decades to characterise seafloor hydrothermal mineralisation, but few studies have been carried out on sulphate minerals. Here we report on a systematic study of the S isotopic composition and rare earth element (REE) chemistry of chimney anhydrite from various types of seafloor hydrothermal vent fields in the Central Indian Ridge, North Fiji Basin, and Tonga intra-oceanic arc. Our results show that sulphate δ34S values of anhydrite cluster around that of seawater sulphate, indicating a significant role for fluid–seawater mixing during anhydrite precipitation. However, some anhydrite has δ34S values lower than that of seawater. This likely reflects sulphate derived from magmatic SO2 disproportionation. Chondrite-normalised REE patterns of the anhydrite are not uniform on the scale of individual grains and/or between each type of hydrothermal vent field. The REE compositions of the anhydrite do not have a clear relationship with the REE compositions of the primary host rocks with which the hydrothermal fluids interacted. This indicates that the REEs are not sensitive indicators of the host rock compositions, even though the host rocks are the dominant source of REEs in the seafloor hydrothermal fluids. In contrast, anhydrite REE concentrations and Eu anomalies are correlated with δ34S values and the redox state of the hydrothermal fluids, respectively. We suggest that relatively REE-enriched anhydrite is formed by efficient leaching of REEs from host rocks by acidic magmatic fluids (i.e., a low pH), whereas a low redox potential of the hydrothermal fluids is the most important factor controlling Eu mobility. The original concentrations of REEs supplied to the hydrothermal fluids can also be modified by fluid boiling and fluid–seawater mixing. The former produces light REE-depleted anhydrite because the availability of chloride ligands decreases in low-density vapor-dominated boiled fluids. In situ geochemical analysis of anhydrite on the intra-grain scale shows that high degrees of fluid–seawater mixing contribute to the relatively low REE concentrations and positive Eu anomalies. As such, our results indicate that the REE systematics of anhydrite are mainly controlled by the combined effects of fluid conditions (i.e., redox state, pH, and Cl concentrations) and sub-seafloor geochemical processes (i.e., magmatic input, fluid boiling, and seawater mixing) rather than the nature of the source materials. In situ analysis of anhydrite grains is a useful tool for constraining variable hydrothermal mineralisation conditions during chimney growth, which cannot be solely inferred from geochemical studies of sulphide minerals, particularly in inactive and relict systems where the hydrothermal fluids cannot be sampled.

Molecular structural, vibrational spectra, dual descriptor, electronic transition and biological evaluations of ethyl 4‑hydroxy-3-methoxycinnamate using density functional theory

Quantum chemical, spectroscopic and bioactivity studies of pharmacologically active Ethyl 4‑hydroxy 3‑methoxy ethyl cinnamate (EHMC) were investigated. By optimizing the geometric structural parameters, it was theoretically possible to obtain the FTIR &UV–Vis absorbance of the EHMC in both protic and aprotic solvents. PED values were computed, and vibrational assignments were identified. The TD-DFT approach and the IEFPCM model were used for simulating the UV spectra of the EHMC chemical. This study presents a comprehensive analysis of molecular parameters, including topological features of electron density, Reduced density gradient (RDG), NBO hyperconjugative interaction energies, frontier molecular energies (FMO) energies, and chemical reactivity descriptors across various solvents. MEP distinguishes between nucleophilic & electrophilic locations and determines a molecule's 3D charge distribution. Electrophilic and nucleophilic strength inside a molecule explained by Fukui function and Mullikan's charge. Furthermore, drug likeness and ADMET analysis were conducted to ascertain the biological characteristics and molecular docking investigation was also performed to explore the biological function of the title substance.

Chemical composition, antifungal, antibiofilm, and molecular docking studies of Syzygium dyerianum essential oil.

The current study describes the chemical composition, antifungal, antibiofilm, antibacterial and molecular docking studies of Syzygium dyerianum growing in Malaysia. The essential oil was obtained through hydrodistillation and characterized using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The antifungal and antibacterial activities were developed using the broth microdilution assay, whereas the effect on the microbial biofilms was determined using a semi-quantitative static biofilm assay. A total of 31 components were identified, which represent 99.5 % of the essential oil. The results revealed that the essential oil consisted mainly of β-pinene (15.6 %), α-terpineol (13.3 %), α-pinene (11.1 %), caryophyllene oxide (8.8 %), limonene (8.1 %), borneol (6.0 %) and viridiflorol (5.1 %). The results of the microdilution method showed that essential oil exhibited activity against Candida albicans and Streptococcus mutans with minimal inhibitory concentration values of 125 and 250 μg/mL, respectively. Furthermore, essential oil decreased the biofilm of C.albicans and S.mutans by 20.11±0.27 % and 32.10±4.81 % when treated with 250 μg/mL. The best docking energy was observed with viridiflorol (-29.7 kJ/mol). This study highlights that essential oil can potentially be a natural antifungal, antibacterial, and antibiofilm agent that could be applied in the pharmaceutical and food industries.

Spectroscopic and Theoretical Identifications of Two Structural Motifs of (H2O)10 Cluster.

Precise characterization of archetypal systems of aqueous hydrogen-bonding networks is essential for developing accurate potential functions and universal models of water. The structures of water clusters (H2O)n (n = 2-9) have been verified recently through size-specific infrared spectroscopy with a vacuum ultraviolet free electron laser (VUV-FEL) and quantum chemical studies. For (H2O)10, the pentagonal prism and butterfly motifs were proposed to be important building blocks and were observed in previous experiments. Here we report the size-specific infrared spectra of (H2O)10 via a joint experimental and theoretical study. Well-resolved spectra provide a unique signature for the coexistence of pentagonal prism and butterfly motifs. These (H2O)10 motifs develop from the dominant structures of (H2O)n (n = 8, 9) clusters. This work provides an intriguing prelude to the diverse structure of liquid water and opens avenues for size-dependent measurement of larger systems to understand the stepwise formation mechanism of hydrogen-bonding networks.