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Microplastics (MPs), an emerging pollutant, widely co-occur with polycyclic aromatic hydrocarbons (PAHs) in the environment. Therefore, the interaction between MPs and PAHs has been the focus of much attention in recent years. In this study, three types of MPs, i.e., polypropylene, polystyrene, and poly(vinyl chloride), with the same main chain were selected as the adsorbents, with phenanthrene (PHE) as the representative PAHs. The adsorption mechanisms were explored from the perspective of the molecular spectral level using a combination of Fourier transform infrared spectroscopy (FT-IR) with a two-dimensional correlation technique. The adsorption kinetics results showed that the adsorption of PHE on the three MPs was dominated by chemisorption. However, the FT-IR analysis results indicated that no new covalent bond was created during the adsorption process. Based on the above research, a generalized two-dimensional (2D) correlation spectral technique was employed to investigate the sequence of functional group changes during the adsorption process for different MPs. Furthermore, the hybrid 2D correlation spectral technique explored the effect of side groups attached to the main chain molecules of MPs on adsorption. The results showed that for all three MPs, the functional groups in the side chain have a higher affinity for PHE, which is due to their higher hydrophobicity. This study provides a feasible way to analyze the adsorption of pollutants on MPs, and the results are important for understanding the adsorption interaction between PAHs and MPs in the aquatic environment. [ABSTRACT FROM AUTHOR]

High-energy chemistry is a method of accelerating chemical reactions by transferring copious amounts of energy to individual molecules. The synthesis of acetylene and benzene is a valuable chemical process used in many organic products. The article proposes an original scheme of experimental setup and technology for plasma-activated methane conversion into acetylene and benzene. The system enables the creation of two distinct active zones within the reactor: the "hot zone," where plasma and active elements are generated, and the "relaxation zone," where the synthesis of organic products occurs. The optimal temperature of the blowing gas, i.e., the gas that propels the plasma reactor walls, has been found to be a crucial factor in heat removal from reaction zones. This temperature has been observed to vary within an interval of 290–310°K, while the reactor gas pressure has been identified as a significant variable within a range of 10–40 mbar. These two factors have been identified as the primary determinants of the yield of products, with acetylene yields reaching approximately 70–80% and maximal benzene yields reaching 40%. Furthermore, the duration of plasma exposure is a critical variable in methane conversion. The optimal acetylene yield of 80% was achieved when the reactor was operated in stationary mode for 15 s. A variation of the input gas flow in flow mode within an interval of 5–15 m3/h resulted in a decrease in the yield of acetylene to 60 percent, while an increase in the benzene yield up to 50 percent was observed. This was accompanied by an overall increase in the total volume of products produced per time unit. A general qualitative model of methane reforming is proposed, combining methane dehydration in the plasma flame with direct synthesis of acetylene from carbon and hydrogen atoms in the relaxation zone. Benzene formation occurs through the trimerization of acetylene molecules under heat dissipation near the reactor walls. [ABSTRACT FROM AUTHOR]

Invasive pneumococcal disease (IPD) is a major cause of morbidity and mortality worldwide, particularly in the pediatric population (children and infants), with high rates of hospitalization and death. This study aimed to create and validate a classifier for Streptococcus pneumoniae serotyping using Fourier-transform infrared (FT-IR) spectroscopy as a rapid alternative to the classical serotyping technique. In this study, a database comprising 76 clinical isolates, including 18 serotypes (predominantly serotypes 19A, 6C, and 3) of S. pneumoniae from pediatric patients with IPD, was tested at a tertiary pediatric hospital in southern Brazil during 2016–2023. All isolates were previously serotyped using the Quellung reaction, and 843 FT-IR spectra were obtained to create a classification model using artificial neural network (ANN) machine learning. After the creation of this classifier, internal validation was performed using 384 spectra as the training dataset and 459 as the testing dataset, resulting in a predictive accuracy of 98% for serotypes 19A, 6, 3, 14, 18C, 22F, 23A, 23B, 33F, 35B, and 9N. In this dataset, serotypes 10A/16F, 15ABC, and 7CF could not be differentiated and were, therefore, grouped as labels. FT-IR is a promising, rapid, and low-cost method for the phenotypic classification of S. pneumoniae capsular serotypes. This methodology has significant implications for clinical and epidemiological practice, improving patient management, monitoring infection trends, and developing new vaccines. [ABSTRACT FROM AUTHOR]

Polyphenolic compounds are considered one as the most important plant-originated species with antioxidant properties. This paper focuses on exploring the structure and antiradical properties of supramolecular complexes derived from the selected polyphenolic (caffeic and protocatechuic) acids and isomers of pyridinecarboxamide. The chemical interactions between polyphenolic acids and carboxamides were analyzed using FT–IR spectroscopy. The thermal behavior of the solid phases was tested with the help of thermal analysis via thermogravimetry (TG) coupled with differential scanning calorimetry (DSC). The antiradical activity was determined by using the ABTS method (2,2′-azino-bis(3-ehylbenzothiazoline-6-sulfonic acid). The obtained results indicate that the solutions prepared by dissolving the solid materials exhibited better antiradical activity than the binary mixtures prepared by mixing the stock reagents' solutions. These studies confirmed that supramolecular complexes derived from polyphenolic compounds and N-heterocyclic entities may constitute a quite interesting material for future research. [ABSTRACT FROM AUTHOR]

The local application of broad-spectrum antibiotics via polymeric drug delivery systems is a promising alternative to their systemic administration in wound healing, prevention and treatment of infections associated with surgical implants. However, low and poorly controlled loading efficiency and 100% burst release are common problems for the materials with weak physical interaction between antibiotics and polymeric matrices. Here, we report a new multifunctional carboxymethyl chitosan (CMC) cryogel, which efficiently prevents bacterial adhesion to the surface, kills bacteria in the solution via controlled release of ciprofloxacin (CIP), and promotes fibroblast proliferation. The suggested approach is based on CIP loading to Zn2+-chelated CMC cryogel via the ligand exchange reaction. We have shown that, due to the strong binding of Zn2+ to CMC, the antibacterial effect and toxicity to fibroblasts of CMC-Zn-CIP cryogels were mainly determined by the content of loaded CIP, which can be precisely controlled via Zn2+ content in cryogel. CMC cryogels containing 20 mgZn/g can be loaded with CIP amounts sufficient to completely suppress the growth of hospital strain Klebsiella oxytoca with MIC of 0.125 µg/mL, while maintaining a fibroblast viability at the level of 85–90%. [ABSTRACT FROM AUTHOR]

In recent years, the femtosecond laser ablation of hard dental tissues has stimulated great interest in preparing accurate and reproducible dental cavities. Many studies on the changes induced in the surface morphology, structure, and composition of human teeth have been performed using various advanced experimental techniques. Vibrational spectroscopies such as Fourier transform infrared (FT-IR) and Raman spectroscopy have been adopted for obtaining precise information about changes induced by femtosecond laser ablation in human teeth. Their two main components, dentin and enamel, have been carefully investigated. The analysis of the vibrational spectra has allowed for the identification of the optimal working parameters for efficient laser ablation processes. In the present review, a brief description of the abovementioned vibrational techniques is reported, and the principal results obtained by these two vibrational spectroscopies in the study of femtosecond laser ablated teeth are summarized and analyzed. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) are extensively studied as potent antibacterial agents targeting antibiotic-resistant pathogens. Cellular damage induced through various mechanisms that can affect multiple cell components like the outer membrane, enzymes, and proteins is closely linked to their chemical and morphological characteristics. We investigated the impact of AgNPs’ size on their antibacterial effectiveness using two differently sized nanoparticles: silver nanoparticle-Citrus limon (AgCL) with an average size of 21 nm and silver nanoparticle-Citrus sinensis (AgCS) with an average size of 13 nm, derived from C. limon and C. sinensis through environmentally friendly methods. The study evaluated their antibacterial effects by assessing morphology changes via scanning electron microscopy, metabolic alterations using Fourier transform infrared (FT-IR) spectroscopy, and oxidative stress responses through biochemical markers in Klebsiella pneumoniae cells exposed to AgNPs. The results showed that both AgCL and AgCS exhibited remarkable antibacterial activity, evidenced by inhibition zones of 14 ± 1.5 and 16 ± 1.0 mm, respectively. Morphological changes in K. pneumoniae cells treated with AgNPs were size dependent, with notable alterations noted. FT-IR spectroscopy revealed size and concentration-dependent biochemical changes, particularly in shifts in functional groups involved in the fluidity of cell wall lipid, and protein structure. Exposure to AgNPs led to increased oxidative stress markers like lipid peroxides and reduced levels of enzymatic and non-enzymatic antioxidants, more prominently observed with smaller AgCS nanoparticles (13 nm). AgNPs induce oxidative stress and morphological changes in K. pneumoniae strains, with smaller nanoparticles demonstrating greater efficacy. These findings underscore the importance of nanoparticle size in optimizing the antibacterial properties against pathogens.

In recent years, the femtosecond laser ablation of hard dental tissues has stimulated great interest in preparing accurate and reproducible dental cavities. Many studies on the changes induced in the surface morphology, structure, and composition of human teeth have been performed using various advanced experimental techniques. Vibrational spectroscopies such as Fourier transform infrared (FT-IR) and Raman spectroscopy have been adopted for obtaining precise information about changes induced by femtosecond laser ablation in human teeth. Their two main components, dentin and enamel, have been carefully investigated. The analysis of the vibrational spectra has allowed for the identification of the optimal working parameters for efficient laser ablation processes. In the present review, a brief description of the abovementioned vibrational techniques is reported, and the principal results obtained by these two vibrational spectroscopies in the study of femtosecond laser ablated teeth are summarized and analyzed.

The dielectric, thermodynamic and volumetric measurements of neat 2-ethoxyethanol, neat ethanol and their binary mixtures have been carried out using time domain technique at 10°C–25°C with a variation of 5°C. Various dielectric parameters are calculated from complex dielectric spectra and are used to compute Kirkwood correlation factor, Bruggeman factor and activation thermodynamic parameters. These parameters are used to predict heteromolecular hydrogen bonding between associating molecules. The classical and non-classical type H-bonding interactions among the molecules are predicted using FT-IR spectroscopy. [ABSTRACT FROM AUTHOR]

Glasses with compositions 46.1B2O3-24.4Na2O-26.9CaO.2.6P2O5, xZnO/MgO-22.0B2O3-(24.4-x)Na2O-27CaO-2.5P2O5 (x = 2.5, 3 mol%) and 1.5ZnO-1.5MgO-22.0B2O3-21.5.Na2O-27CaO-2.5P2O5 were melted by melt quenching technique. The densities of the glasses were measured by the Archimedes principle, using an analytical scale. Glasses possess densities in the 2.538 to 2.623 g cm-1 range. The short-range order was also discussed from the molar volume Vm, cm3 mol-1, and oxygen packing density point of view. The molar volume of the glasses varies between 26.566 - 27.420 cm3 mol-1 and the oxygen packing density is between 73.669 to 76.262 mol cm-3x. The Furie transform infrared spectroscopy and Raman spectroscopy were performed to study the main structural units constituting the structure of the samples. The main structural units were found to be BO3 and BO4 probably connected in pentaborate and triborate structural units. The influence of the ZnO and MgO on the structure and chemical bonding of the glasses was discussed. [ABSTRACT FROM AUTHOR]

Manouri, a protected designation of origin (PDO) cheese, is one of the most popular whey cheeses produced in Greece. The objective of the current study was to investigate if there are differences between artisanal and industrial Manouri cheeses regarding microbiological quality, volatile organic compounds (VOCs) profile and other quality parameters (colour, texture), sensory attributes and spectral characteristics detected by Fourier transform infrared spectroscopy (FT-IR) that may discriminate the samples. Differences were detected in the population of the dominant microbial groups, especially for lactic acid bacteria (LAB), Enterobacteriaceae and yeast counts. No discrimination was attained from the physicochemical analyses, except for the pH values. A total of 50 VOCs were identified, including ketones, lactones, free fatty acids, aldehydes, esters, alcohols and hydrocarbons. Sensory evaluation was carried out using a quantitative descriptive analysis (QDA) panel and a consumer panel. Consumers showed a preference for the artisanal Manouri, and the QDA panel revealed significant differences in 11 out of the 17 sensory attributes. Colour and texture analyses were also performed and showed specific differences in yellowness, as well as in fracturability and hardness. FT-IR spectral analysis demonstrated potential discrimination related to the phospholipid content and profile of artisanal and industrial Manouri. [ABSTRACT FROM AUTHOR]

Mitigating the impact of fossil fuels in diesel engines is crucial for addressing environmental issues, and alcohol-based fuel additives play a pivotal role. As key carriers of hydrogen, these additives have attracted considerable attention for their potential to reduce our dependence on fossil fuels. This study investigates the impact of blending diesel with various alcohols—n-butanol, n-octanol, and ethanol—at blending ratios of 20 and 50 vol% on combustion characteristics, emissions, and soot nanostructure in a compression ignition (CI) engine. Blending with n-butanol and ethanol notably retarded ignition delay and shortened combustion duration, whereas n-octanol's influence was minimal. Emission analyses highlighted that alcohol additions generally curtail nitrogen oxides (NO x) emissions, with 20 vol% n-butanol or n-octanol effectively diminishing unburned hydrocarbon (HC) emissions. An in-depth analysis of particulate matter (PM) emissions revealed that incorporating 50 vol% n-butanol or 20 vol% ethanol can significantly reduce PM emissions, achieving a reduction of up to 68% under various engine conditions. The examination of soot characteristics via Raman spectroscopy analysis highlighted an increased oxidative reactivity in soot particles when using n-octanol and ethanol blends. Additionally, soot samples obtained from alcohol-diesel blends displayed a heightened presence of C O groups, as identified through Fourier-transform infrared (FT-IR) spectroscopy analysis. This research offers profound insights into the intricate effects of alcohol-diesel blending on engine combustion and emissions. • Comprehensive study of diesel blended with various alcohols at different conditions. • Significant effects of n-butanol and ethanol on gas emissions are distinctly observed. • Up to 68% reduction in PM emissions achieved with 50% n-butanol or 20% ethanol. • Raman and FTIR spectroscopy reveal detailed soot properties from engine emissions. • n-Octanol and ethanol blends enhance soot's oxidative reactivity, deepening insights. [ABSTRACT FROM AUTHOR]

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Vibrational spectra generate a profile which is a distinct fingerprint that may be used to screen and scan samples and can be used for taxonomic studies. Fourier-transformed Infrared Spectral Analysis can provide the vibrational modes in the coelomic fluid from earthworms. Five species of earthworms belonging to three different families (Megascolecidae, Moniligastridae, and Rhinodrilidae) including four different genera (Perionyx, Megascolex, Pontoscolex, and Drawida) were selected for analysis. Out of the five species, the earthworm Megascolex cochinensis is endemic to Kerala and the Western Ghats, Pontoscolex corethrurus is an exotic peregrine, and Perionyx sansibaricus is a native peregrine. Homogeneity of the means of percentage of transmittance by one-way ANOVA, shows that all five species are not homogenous. Significant differences in peak expression have been noticed when comparing these samples. From this study, it is clear that spectral fingerprints can differentiate the four different genera (Perionyx, Megascolex, Pontoscolex, and Drawida) across the three families. [ABSTRACT FROM AUTHOR]

Abstract Background Plant extracts have attracted significant interest among researchers due to their potential bioactivity and crucial contribution to the production of pharmaceutical compounds. In this study, the primary objective was to extract, analyze and characterize the bioactive compounds found in the methanol root extract of Datura fastuosa (D. fastuosa). This was achieved using various analytical techniques such as gas chromatography/mass spectrometry (GC–MS), ultra-violet visible spectrophotometry, Fourier-transform infrared (FT-IR), nuclear magnetic radiation spectrometry (NMR) and DPPH free radical scavenging activity assay. Results GC–MS analysis of the methanol root crude extract identified 49 compounds. Three compounds were isolated via column chromatography; one was pure, with a sharp melting point and clean IR spectrum, while the other two showed broad melting points and IR interferences. Comprehensive investigation of the pure extract revealed a UV profile with two distinct bands (300–800 nm) and confirmed functional groups (alcohol, alkanes, alkenes, carbonyl, methylene, and methyl) through FT-IR analysis. The 1HNMR (proton nuclear magnetic resonance spectroscopy) signal confirmed the presence of forty-nine non-equivalent protons, 13CNMR (Carbon-13 nuclear magnetic resonance spectroscopy) signal confirmed the presence of 32 non-equivalent carbons and DEPT-135 (distortionless enhancement by polarization transfer-135) signal confirmed the presence of 24 carbons (17 for odd and 7 for even) which are protons containing carbons in the compound. Combining the above mentioned analyses with data obtained from the GC/MS analysis of National Institute of Standards and Technology (NIST) library, the isolated pure compound exhibited a structural similarity to 1-(7-(3-hydroxyphenyl)-1,1,4a,5,6,9,10a,10b-octamethyl-1,2,3,4,4a,4b,6a,7,8,9,10,10a,10b,11,12,12a-hexadecahydrochrysen-2-yl)propan-1-one, with a chemical formula of C35H50O2. Conclusions The presence of various notable compounds, including phenolics, flavonoids, alkaloids, steroids etc., within the methanol root extract of D. fastuosa signifies its pharmacological potential. The methanol crude extract demonstrated antioxidant potential compared to standard ascorbic acid, exhibiting DPPH scavenging activity. Previous research has demonstrated the bioactivity of some of these compounds, further elucidating the plant’s medicinal properties. These findings not only suggest opportunities for developing synthetic drugs but also underscore its direct therapeutic potential in addressing diverse ailments.

Using the auto combustion sol-gel method, nanoferrite crystalline aligns of Dy3+ replaced Zn-Fe spinel ferrite with the chemical formula DyxZn1-xFe2-xO4 (x= 0.00, 0.05) were successfully synthesized. In this process, citric acid was utilized as energy (fuel) in a 3:1 ratio to metal nitrate. Using XRD and FT-IR, the crystal structure and phase of dysprosium zinc was examined. Using the XRD method, the crystal size, lattice constant, cation distribution, and porosity were ascertained. FT-IR spectroscopy is used to infer structural study and the redistribution of cations between octahederal (A) and tetrahederal (B) site of Zn material. According to morphological research, the temperature during sintering is what causes grain to form and grow. Utilizing the Hysteresis Loop Technique, saturation magnetism and magneton number are determined. In Zn-Fe ferrite, the saturation magnetization rises with increasing density x, utilizing the Sol-gel auto-combustion method at a comparatively low temperature. Using nitrate citrate, the nanocrystallite DyxZn1-xFe2-xO4 was created. The combustion process and chemical gelation are unique. Using citric acid as a catalyst, their metal nitrates nanoferrites underwent a successful chemical reaction and were obtained as a dried gel. FT-IR, UV-Visible, VSM and XRD were used to characterize the produced nanoferrite powders. Magnetization and hysteresis were measured using the VSM technique. The FT-IR verifies that the synthesized substance is ferrite. The size of the nanocrystalline ferrite material, DyxZn1-xFe2-xO4, was determined by X-ray using the Scherrer method to be between 16.86 to 12.72 nm average crystallite size. Magnetization and hysteresis were measured using the VSM technique.

Background: Plant extracts have attracted significant interest among researchers due to their potential bioactivity and crucial contribution to the production of pharmaceutical compounds. In this study, the primary objective was to extract, analyze and characterize the bioactive compounds found in the methanol root extract of Datura fastuosa (D. fastuosa). This was achieved using various analytical techniques such as gas chromatography/mass spectrometry (GC–MS), ultra-violet visible spectrophotometry, Fourier-transform infrared (FT-IR), nuclear magnetic radiation spectrometry (NMR) and DPPH free radical scavenging activity assay. Results: GC–MS analysis of the methanol root crude extract identified 49 compounds. Three compounds were isolated via column chromatography; one was pure, with a sharp melting point and clean IR spectrum, while the other two showed broad melting points and IR interferences. Comprehensive investigation of the pure extract revealed a UV profile with two distinct bands (300–800 nm) and confirmed functional groups (alcohol, alkanes, alkenes, carbonyl, methylene, and methyl) through FT-IR analysis. The 1HNMR (proton nuclear magnetic resonance spectroscopy) signal confirmed the presence of forty-nine non-equivalent protons, 13CNMR (Carbon-13 nuclear magnetic resonance spectroscopy) signal confirmed the presence of 32 non-equivalent carbons and DEPT-135 (distortionless enhancement by polarization transfer-135) signal confirmed the presence of 24 carbons (17 for odd and 7 for even) which are protons containing carbons in the compound. Combining the above mentioned analyses with data obtained from the GC/MS analysis of National Institute of Standards and Technology (NIST) library, the isolated pure compound exhibited a structural similarity to 1-(7-(3-hydroxyphenyl)-1,1,4a,5,6,9,10a,10b-octamethyl-1,2,3,4,4a,4b,6a,7,8,9,10,10a,10b,11,12,12a-hexadecahydrochrysen-2-yl)propan-1-one, with a chemical formula of C35H50O2. Conclusions: The presence of various notable compounds, including phenolics, flavonoids, alkaloids, steroids etc., within the methanol root extract of D. fastuosa signifies its pharmacological potential. The methanol crude extract demonstrated antioxidant potential compared to standard ascorbic acid, exhibiting DPPH scavenging activity. Previous research has demonstrated the bioactivity of some of these compounds, further elucidating the plant's medicinal properties. These findings not only suggest opportunities for developing synthetic drugs but also underscore its direct therapeutic potential in addressing diverse ailments. [ABSTRACT FROM AUTHOR]

Green synthesis employs environmentally friendly, biodegradable substances for the production of nanomaterials. This study aims to develop an innovative method for synthesizing silver nanoparticles (AgNPs) using a methanolic extract of Fomes fomentarius L. Fr. as the reducing agent and to assess the potential antibacterial properties of the resulting nanoparticles. The successful synthesis of AgNPs was confirmed through characterization techniques such as UV-visible (UV-Vis) spectrophotometry, Fourier-transform infrared spectroscopy (FT-IR), and powder X-ray diffraction (PXRD). The UV-Vis analysis revealed an absorption peak at 423 nm, while FT-IR identified key phytochemical compounds involved in the reduction process. PXRD analysis indicated a face-centered cubic (fcc) structure with prominent peaks observed at 2θ = 38°, 44.6°, 64.6°, and 78°, confirming the crystalline nature of the AgNPs, with a crystallite diameter of approximately 24 nm, consistent with TEM analysis. The synthesized AgNPs demonstrated significant antibacterial activity, particularly against S. aureus, with higher efficacy against gram-positive bacteria. [ABSTRACT FROM AUTHOR]

Protein conformation is affected by interaction of several small molecules resulting either stabilization or disruption depending on the nature of the molecules. In our earlier communication, Hg2+ was known to disrupt the native structure of α-Cgn A leading to aggregation (Ansari, N.K., Rais, A. & Naeem, A. Methotrexate for Drug Repurposing as an Anti-Aggregatory Agent to Mercuric Treated α-Chymotrypsinogen-A. Protein J (2024). https://doi.org/10.1007/s10930-024-10187-z). Accumulation of β-rich aggregates in the living system is found to be linked with copious number of disorders. Here, we have investigated the effect of varying concentration of doxorubicin (DOX) i.e. 0-100 µM on the preformed aggregates of α-Cgn A upon incubation with 120 µM Hg2+. The decrease in the intrinsic fluorescence and enzyme activity with respect to increase in the Hg2+ concentration substantiate the formation of aggregates. The DOX showed the dose dependent decrease in the ThT fluorescence, turbidity and RLS measurements endorsing the dissolution of aggregates which were consistent with red shift in ANS, confirming the breakdown of aggregates. The α-Cgn A has 30% α-helical content which decreases to 3% in presence of Hg2+. DOX increased the α-helicity to 28% confirming its anti-aggregatory potential. The SEM validates the formation of aggregates with Hg2+ and their dissolution upon incubation with the DOX. Hemolysis assay checked the cytotoxicity of α-Cgn A aggregates. Docking revealed that the DOX interacted Lys203, Cys201, Cys136, Ser159, Leu10, Trp207, Val137 and Thr134 of α-Cgn A through hydrophobic interactions and Gly133, Thr135 and Lys202 forms hydrogen bonds. [ABSTRACT FROM AUTHOR]

In this work, we investigate the structural parameters that affect water adsorption on amorphous carbon nitride thin films synthesized by pulsed laser deposition. The study includes the case of ablation of graphite targets within molecular nitrogen and within a stream of nitrogen plasma afterglow. The results obtained showed that, the effect of Csp2-Csp2 bonds concentration on the adsorption of water molecules depends strongly on the ratio and distortion of the hexagonal rings. Furthermore, analysis of the spectral data showed that, the relationship between the hydrogen bonding strength of water molecules with the film surface and the concentration of Csp2-Csp2 bonds takes a specific mathematical formula in the case of structures composed mainly of hexagonal rings. [ABSTRACT FROM AUTHOR]

Expanding on earlier observations, we show that many melanin materials, in vitro synthesized from a wide range of precursors, can be fractionated into a dark-colored precipitate and a near-colorless, dispersible fraction. The dispersible fractions exhibited absorbance in the UVA and UVB range of the electromagnetic spectrum, but none in the visible range. In addition, fluorescent properties were associated with all dispersible fractions obtained. FT-IR spectroscopic analyses were performed to compare both types of fractions. Overall, it appears that some of the properties associated with melanin (UV absorbance, fluorescence) may not necessarily reside in the dark-colored portion of melanin, but in a colorless fraction of the material. It remains to be seen whether any of these in vitro observations have any relevance in vivo. However, we raise the possibility that the presence of a colorless fraction within melanin materials and their associated properties may have received inadequate attention. Given the important association between melanin, UV protection, and skin cancer, it is worthwhile to consider this additional aspect of melanin chemistry. [ABSTRACT FROM AUTHOR]

The fermentation of acorns and sorghum is an ancient practice among the inhabitants of northeastern Algeria. This study aimed to establish the traditional fermentation processes of acorns and sorghum through a regional survey conducted in Algeria. Additionally, it investigated the impact of fermentation on the physicochemical, functional, antioxidant, and pasting properties, as well as the FT-IR spectroscopic profiles of the flours derived from these fermented materials. Characteristics of fermented sorghum and acorn flours were compared with those of non-fermented flours. The study included a survey that was carried out in Algeria at the regional level to establish the traditional processes for fermented acorns and sorghum. The key findings reveal the existence of two production methods: the first, the oldest, involves fermentation in underground pits called Matmor, while the second, more recent, is conducted outside the Matmor. Most manufacturers employed the new process outside of the Matmor, usually in various sized and shaped containers to meet market demand. Acorns and sorghum flour, obtained by drying and grinding fermented acorns and fermented sorghum grains according to the process carried out outside the Matmor, are characterized by a unique biochemical, functional, and structural composition. Detailed analysis of the flours showed a significant decrease in their physicochemical properties after fermentation, with a simultaneous overall increase in antioxidant activity. Moreover, FT-IR spectroscopy suggests that fermentation differentially affects protein secondary structure and starch crystallinity. [ABSTRACT FROM AUTHOR]

Evidence has suggested that either labile organic carbon (OC) or stable OC play a role in improving aggregate stability. Therefore, this study determined the OC fractions in water stable aggregates (WSA) and their contribution to the formation of the WSA in paddy soils, on the Central Plain of Thailand. Analysis of the OC fractions in the WSA was determined using wet oxidation with hydrogen peroxide (H2O2). The chemical composition of the organic compounds in the WSA was investigated using Fourier transform mid-infrared (FT-IR) spectroscopy. The results showed that the WSA content of the studied soils significantly increased with increasing organic and inorganic cementing/flocculating agents, such as soil organic carbon, clay, polyvalent cations, and sesquioxides. The labile OC and stable OC contents in the WSA also significantly increased with increased WSA content, suggesting the physical protection of OC fractions against microbial decomposition. The FT-IR analysis revealed that labile OC in the WSA, both before and after wet oxidation with H2O2, was dominated by polysaccharides, supporting the physical protection of labile OC by the WSA. Paddy soils containing higher organic and inorganic cementing/flocculating agents had higher stable OC, such as hydrophobic aromatic compounds, in the WSA, compared to paddy soils containing lower organic and inorganic cementing/flocculating agents. In turn, the WSA content of the soils in this study significantly increased with increases in the hydrophobic aromatic compounds in the WSA, suggesting the important role of stable hydrophobic organic compounds in enhancing the formation and stabilization of soil aggregates in these paddy soils. [ABSTRACT FROM AUTHOR]

Sepsis is a life-threatening condition arising from a dysregulated host immune response to infection, leading to a substantial global health burden. The accurate identification of bacterial pathogens in sepsis is essential for guiding effective antimicrobial therapy and optimising patient outcomes. Traditional culture-based bacterial typing methods present inherent limitations, necessitating the exploration of alternative diagnostic approaches. This study reports the successful application of Fourier-transform infrared (FT-IR) spectroscopy in combination with chemometrics as a potent tool for the classification and discrimination of microbial species and strains, primarily sourced from individuals with invasive infections. These samples were obtained from various children with suspected sepsis infections with bacteria and fungi originating at different sites. We conducted a comprehensive analysis utilising 212 isolates from 14 distinct genera, comprising 202 bacterial and 10 fungal isolates. With the spectral analysis taking several weeks, we present the incorporation of quality control samples to mitigate potential variations that may arise between different sample plates, especially when dealing with a large sample size. The results demonstrated a remarkable consistency in clustering patterns among 14 genera when subjected to principal component analysis (PCA). Particularly, Candida, a fungal genus, was distinctly recovered away from bacterial samples. Principal component discriminant function analysis (PC-DFA) allowed for distinct discrimination between different bacterial groups, particularly Gram-negative and Gram-positive bacteria. Clear differentiation was also observed between coagulase-negative staphylococci (CNS) and Staphylococcus aureus isolates, while methicillin-resistant S. aureus (MRSA) was also separated from methicillin-susceptible S. aureus (MSSA) isolates. Furthermore, highly accurate discrimination was achieved between Enterococcus and vancomycin-resistant enterococci isolates with 98.4% accuracy using partial least squares-discriminant analysis. The study also demonstrates the specificity of FT-IR, as it effectively discriminates between individual isolates of Streptococcus and Candida at their respective species levels. The findings of this study establish a strong groundwork for the broader implementation of FT-IR and chemometrics in clinical and microbiological applications. The potential of these techniques for enhanced microbial classification holds significant promise in the diagnosis and management of invasive bacterial infections, thereby contributing to improved patient outcomes. [ABSTRACT FROM AUTHOR]

Understanding the thermal properties of zeolites is crucial for their industrial applications. This study explores the thermal stability and dehydration process of clinoptilolite using high-temperature X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Clinoptilolite's thermal decomposition was monitored from 25 °C to 1200 °C, with results analyzed based on its crystal structure. Principal components analysis (PCA) of the DRIFT spectra indicated progressive water removal and dehydration upon heating, leading to the formation of hydrogen bonds. Thermogravimetric analysis (TGA) revealed a two-step endothermic weight loss: initially, physically adsorbed water was lost up to 100 °C, followed by the removal of tightly bound water and hydroxyl groups until 800 °C. Clinoptilolite remained the dominant phase up to 800 °C, after which albite and cristobalite took over. Rietveld refinement showed that the sample initially contained 70% clinoptilolite, 24% albite, and 6% cristobalite. Above 800 °C, clinoptilolite disappeared, leaving 93% albite and 7% cristobalite. FT-IR spectra changes due to water loss were evident: drying of adsorbed water occurred up to 75 °C and minimal changes were observed from 75 °C to 135 °C, followed by further dehydration until 240 °C. Complete dehydration was confirmed by the disappearance of OH stretching vibration bands by 395 °C, consistent with TGA findings. [ABSTRACT FROM AUTHOR]

The experimental IR spectra of (S)-4′-(1-methylheptyloxycarbonyl) biphenyl-4-yl 4-[2-(2,2,3,3,4,4,4-heptafluorobutoxy) ethyl-1-oxy]-2-fluorobenzoate in the crystal phase are analyzed with the help of dispersion-corrected density functional theory (DFT+D3) calculations for isolated molecular monomer and dimer models, and a periodic model computed at the extended density functional tight-binding (xTB) level of theory. It is found that the frequency scaling coefficients obtained with the results of the molecular calculations are good matches for the crystal phase, being close to 1. The molecular and periodic models both confirm that varied intra- and intermolecular interactions are crucial in order to reproduce the broadened shape of the experimental band related to C=O stretching; the key factors are the conjugation of the ester groups with the aromatic rings and the varied intermolecular chemical environments, wherein the C=O group that bridges the biphenyl and F-substituted phenyl groups seems particularly sensitive. The C=O stretching vibrations are investigated as a function of temperature, covering the range of the crystal, smectic CA*, smectic C* and isotropic liquid phases. The structure changes are followed based on the X-ray diffraction patterns collected in the same temperatures as the IR spectra. The experimental and computational results taken together indicate that the amount of weak C=O...H-C hydrogen bonds between the molecules in the smectic layers decreases with increasing temperature. [ABSTRACT FROM AUTHOR]

In this work, we synthesized and confirmed the structure of several alkaloid N-oxides using mass spectrometry and Fourier-transform infrared spectroscopy. We also investigated their reduction mechanisms using voltammetry. For the first time, we obtained alkaloid N-oxides using an oxidation reaction with potassium peroxymonosulfate as an oxidant. The structure was established based on the obtained fragmentation mass spectra recorded by LC-Q-ToF-MS. In the FT-IR spectra of the alkaloid N-oxides, characteristic signals of N-O group vibrations were recorded (bands in the range of 928 cm⁻1 to 971 cm⁻1), confirming the presence of this functional group. Electrochemical reduction studies demonstrated the reduction of alkaloid N-oxides at mercury-based electrodes back to the original form of the alkaloid. For the first time, the products of the electrochemical reduction of alkaloid N-oxides were detected by mass spectrometry. The findings provide insights into the structural characteristics and reduction behaviors of alkaloid N-oxides, offering implications for pharmacological and biochemical applications. This research contributes to a better understanding of alkaloid metabolism and degradation processes, with potential implications for drug development and environmental science. [ABSTRACT FROM AUTHOR]

This paper reports on the studies carried out on engraved inscriptions of the Deposition from the Cross by Benedetto Antelami (1150–1230), a relief sculpture conserved in the Cathedral of Parma (Italy). The inscriptions between the characters show residues of colored material in alternating red- and dark-colored stripes. The purpose of this specific investigation was to identify the materials (pigments and organic binders) used for the polychromy that are still present on the relief sculpture. Seven microsamples were taken to carry out laboratory analyses. In red-colored letters, mercury, and sulfur, constituents of the cinnabar (or vermilion) pigment were easily identified by SEM-EDS. This result is confirmed by Raman spectroscopy and XRD measurements. In the dark letters, carbon, iron, and lead are observed. The presence of materials containing metals is compatible with a mastic encrustation technique. FT-IR, Raman, and XRD techniques clearly detect beeswax, which was probably used as a polishing material. Amino acids and lipids that are typical of eggs have been identified by means of GC-MS investigations, suggesting their use as organic components of the mastic encrustation. [ABSTRACT FROM AUTHOR]

Invasive pneumococcal disease (IPD) is a major cause of morbidity and mortality worldwide, particularly in the pediatric population (children and infants), with high rates of hospitalization and death. This study aimed to create and validate a classifier for Streptococcus pneumoniae serotyping using Fourier-transform infrared (FT-IR) spectroscopy as a rapid alternative to the classical serotyping technique. In this study, a database comprising 76 clinical isolates, including 18 serotypes (predominantly serotypes 19A, 6C, and 3) of S. pneumoniae from pediatric patients with IPD, was tested at a tertiary pediatric hospital in southern Brazil during 2016–2023. All isolates were previously serotyped using the Quellung reaction, and 843 FT-IR spectra were obtained to create a classification model using artificial neural network (ANN) machine learning. After the creation of this classifier, internal validation was performed using 384 spectra as the training dataset and 459 as the testing dataset, resulting in a predictive accuracy of 98% for serotypes 19A, 6, 3, 14, 18C, 22F, 23A, 23B, 33F, 35B, and 9N. In this dataset, serotypes 10A/16F, 15ABC, and 7CF could not be differentiated and were, therefore, grouped as labels. FT-IR is a promising, rapid, and low-cost method for the phenotypic classification of S. pneumoniae capsular serotypes. This methodology has significant implications for clinical and epidemiological practice, improving patient management, monitoring infection trends, and developing new vaccines.

Craft beer brewers need to learn process control strategies from traditional industrial production to ensure the consistent quality of the finished product. In this study, FT-IR combined with deep learning was used for the first time to model and analyze the Plato degree and total flavonoid content of Qingke beer during the mashing and boiling stages and to compare the effectiveness with traditional chemometrics methods. Two deep learning neural networks were designed, the effect of variable input methods on the effectiveness of the models was discussed. The experimental results showed that the CARS-LSTM model had the best predictive performance, not only as the best quantitative model for Plato in the mashing (R2p = 0.9368) and boiling (R2p = 0.9398) phases but also as the best model for TFC in the boiling phase (R2p = 0.9154). This study demonstrates the great potential of deep learning and provides a new approach to quality control analysis in beer brewing.

Abstract Our investigation revealed that alterations in sulphur (S) pools are predominantly governed by soil organic carbon (SOC), soil nitrogen (N), microbial biomass, and soil enzyme activities in sandy clay loam (Vertic Ustropept) soil. We employed ten sets of nutrient management techniques, ranging from suboptimal (50% RDF) to super-optimal doses (150% RDF), including NPK + Zn, NP, N alone, S-free NPK fertilizers, NPK + FYM, and control treatments, to examine the interrelation of S with SOC characteristics. Fourier-transform infrared (FT-IR) spectroscopy was utilized to analyze the functional groups present in SOC characterization across four treatments: 100% NPK, 150% NPK, NPK + FYM, and absolute control plots. Principal component analysis (PCA) was then applied to assess 29 minimal datasets, aiming to pinpoint specific soil characteristics influencing S transformation. In an Inceptisol, the application of fertilizers (100% RDF) in conjunction with 10 t ha−1 of FYM resulted in an increase of S pools from the surface to the subsurface stratum (OS > HSS > SO4 2−–S > WSS), along with an increase in soil N and SOC. FT-IR spectroscopy identified cellulose and thiocyanate functional groups in all four plots, with a pronounced presence of carbohydrate—protein polyphenol, sulfoxide (S=O), and nitrate groups specifically observed in the INM plot. The PCA findings indicated that the primary factors influencing soil quality and crop productivity (r2 of 0.69) are SOC, SMBC, SMBN, SMBS, and the enzyme activity of URE, DHA, and AS. According to the study, the combined application of fertilizer and FYM (10 t ha−1) together exert a positive impact on sulphur transformation, SOC accumulation, and maize yield in sandy clay loam soil.