Probing the stability and quality of the cellulose-based Pickering emulsion containing sesamolin-enriched sesame oil by chemometrics-assisted ATR-FTIR spectroscopy

This study presents the employment of Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection and principal component analysis (PCA) to analyze the stability of a Pickering emulsion stabilized by carboxylated-cellulose nanocrystal (cCNC) comprising sesame oil phases with or without sesamolin. FTIR measurements identified an intermolecular hydrogen bond between the ester group of the triglyceride and the carboxyl group of the cCNC to create the emulsion droplet. The spectral bands from the hydroxyl group vibration (3700-3050 cm-1), carbonyl (1744 cm-1), CO groups of the ester triglyceride and cCNC (1160-998 cm-1) markedly discriminated between stabilized and destabilized emulsions. The PCA of FTIR spectra detected the change of molecular interaction during storage according to creaming, aggregation, and coalescence and changes in physicochemical parameters such as droplet size, refractive index, and zeta potential. Hence, PCA enabled the observation of the destabilization of emulsion in real-time.

Identification of sudden cardiac death from human blood using ATR-FTIR spectroscopy and machine learning

OBJECTIVE

The aim of this study is to identify a rapid, sensitive, and non-destructive auxiliary approach for postmortem diagnosis of SCD, addressing the challenges faced in forensic practice.

METHODS

ATR-FTIR spectroscopy was employed to collect spectral features of blood samples from different cases, combined with pathological changes. Mixed datasets were analyzed using ANN, KNN, RF, and SVM algorithms. Evaluation metrics such as accuracy, precision, recall, F1-score and confusion matrix were used to select the optimal algorithm and construct the postmortem diagnosis model for SCD.

RESULTS

A total of 77 cases were collected, including 43 cases in the SCD group and 34 cases in the non-SCD group. A total of 693 spectrogram were obtained. Compared to other algorithms, the SVM algorithm demonstrated the highest accuracy, reaching 95.83% based on spectral biomarkers. Furthermore, by combing spectral biomarkers with age, gender, and cardiac histopathological changes, the accuracy of the SVM model could get 100%.

CONCLUSION

Integrating artificial intelligence technology, pathology, and physical chemistry analysis of blood components can serve as an effective auxiliary method for postmortem diagnosis of SCD.

Species discrimination from hair using ATR-FTIR spectroscopy: Application in wildlife forensics

Hair is a commonly encountered trace evidence in wildlife crimes involving mammals and can be used for species identification which is essential for subsequent judicial proceedings. This proof of concept study aims, to distinguish the black guard hair of three wild cat species belonging to the genus Panthera i.e. Royal Bengal Tiger (Panthera tigris tigris), Indian Leopard (Panthera pardus fusca), and Snow Leopard (Panthera uncia) using a rapid and non-destructive ATR-FTIR spectroscopic technique in combination with chemometrics. A training dataset including 72 black guard hair samples of three species (24 samples from each species) was used to construct chemometric models. A PLS2-DA model successfully classified these three species into distinct classes with R-Square values of 0.9985 (calibration) and 0.8989 (validation). VIP score was also computed, and a new PLS2DA-V model was constructed using variables with a VIP score ≥ 1. External validation was performed using a validation dataset including 18 black guard hair samples (6 samples per species) to validate the constructed PLS2-DA model. It was observed that PLS2-DA model provides greater accuracy and precision compared to the PLS2DA-V model during cross-validation and external validation. The developed PLS2-DA model was also successful in differentiating human and non-human hair with R-Square values of 0.99 and 0.91 for calibration and validation, respectively. Apart from this, a blind test was also carried out using 10 unknown hair samples which were correctly classified into their respective classes providing 100 % accuracy. This study highlights the advantages of ATR-FTIR spectroscopy associated with PLS-DA for differentiation and identification of the Royal Bengal Tiger, Indian Leopard, and Snow Leopard hairs in a rapid, accurate, eco-friendly, and non-destructive way.

Structural characterization of DNA amplicons by ATR-FTIR spectroscopy as a guide for screening metainflammatory disorders in blood plasma

Attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy is a promising rapid, reagent-free, and low-cost technique considered for clinical translation. It allows to characterize biofluids proteome, lipidome, and metabolome at once. Metainflammatory disorders share a constellation of chronic systemic inflammation, oxidative stress, aberrant adipogenesis, and hypoxia, that significantly increased cardiovascular and cancer risk. As a result, these patients have elevated concentration of cfDNA in the bloodstream. Considering this, DNA amplicons were analyzed by ATR-FTIR at 3 concentrations with 1:100 dilution: (IU/mL): 718, 7.18, and 0.0718. The generated IR spectrum was used as a guide for variable selection. The main peaks in the biofingerprint (1800-900 cm-1) give important information about the base, base-sugar, phosphate, and sugar-phosphate transitions of DNA. To validate our method of selecting variables in blood plasma, 38 control subjects and 12 with metabolic syndrome were used. Using the wavenumbers of the peaks in the biofingerprint of the DNA amplicons, was generated a discriminant analysis model with Mahalanobis distance in blood plasma, and 100 % discrimination accuracy was obtained. In addition, the interval 1475-1188 cm-1 showed the greatest sensitivity to variation in the concentration of DNA amplicons, so curve fitting with Gaussian funcion was performed, obtaining adjusted-R2 of 0.993. PCA with Mahalanobis distance in the interval 1475-1188 cm-1 obtained an accuracy of 96 % and PLS-DA modeling in the interval 1475-1088 cm-1 obtained AUC = 0.991 with sensitivity of 95 % and specificity of 100 %. Therefore, ATR-FTIR spectroscopy with variable selection guided by DNA IR peaks is a promising and efficient method to be applied in metainflammatory disorders.

Metallic nanoparticle actions on the outer layer structure and properties of Bacillus cereus and Staphylococcus epidermidis

Although the antimicrobial activity of nanoparticles (NPs) penetrating inside the cell is widely recognised, the toxicity of large NPs (>10 nm) that cannot be translocated across bacterial membranes remains unclear. Therefore, this study was performed to elucidate the direct effects of Ag-NPs, Cu-NPs, ZnO-NPs and TiO2-NPs on relative membrane potential, permeability, hydrophobicity, structural changes within chemical compounds at the molecular level and the distribution of NPs on the surfaces of the bacteria Bacillus cereus and Staphylococcus epidermidis. Overall analysis of the results indicated the different impacts of individual NPs on the measured parameters in both strains depending on their type and concentration. B. cereus proved to be more resistant to the action of NPs than S. epidermidis. Generally, Cu-NPs showed the most substantial toxic effect on both strains; however, Ag-NPs exhibited negligible toxicity. All NPs had a strong affinity for cell surfaces and showed strain-dependent characteristic dispersion. ATR-FTIR analysis explained the distinctive interactions of NPs with bacterial functional groups, leading to macromolecular structural modifications. The results presented provide new and solid evidence for the current understanding of the interactions of metallic NPs with bacterial membranes.

Comparison of ATR-FTIR and NIR spectroscopy for identification of microplastics in biosolids

Biosolids are considered a potentially major input of microplastics (MPs) to agricultural soils. Our study aims to identify the polymeric origin of MPs extracted from biosolid samples by comparing their Attenuated Total Reflection (ATR) - Fourier-transform infrared (FTIR) spectra with the corresponding near-infrared (NIR) spectra. The reflectance spectra were preprocessed by Savitzky-Golay (SG), first derivative (FD) and compared with analogous spectra acquired on a set of fifty-two selected commercial plastic (SCP) materials collected from readily available products. According to the results portrayed in radar chart and built from both ATR-FTIR and NIR spectral datasets, the MPs showed high correlations with polymers such as polyethylene (LDPE, HDPE), polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP) and polyamide (PA), determined in SCP samples. Each unknown MP sample had on average three or more links to several types of SCP, according to the correlation coefficients for each polymer ranging from 0.7 up to 1. The comparison analysis classified the majority of MPs as composed mainly by LDPE/HDPE, according to the top correlation coefficients (r > 0.90). PP and PET were better identified with NIR than ATR-FTIR. In contrast to ATR-FTIR analysis, NIR was unable to identify PS. Based on these results, the primary sources of MPs in the biosolids could be identified as discarded consumer packaging (containers, bags, bottles) and fibers from laundry, disposable glove, and cleaning cloth. SYNOPSIS: Microplastics (MPs) are considered contaminants of emerging concern. This study compares two simple and fast spectroscopy techniques to identify microplastics in the biosolid matrix.

Can Combining Hyaluronic Acid and Physiotherapy in Knee Osteoarthritis Improve the Physicochemical Properties of Synovial Fluid?

Known as the degenerative disease of the knee with the highest prevalence, knee osteoarthritis (KOA) is characterized by a gradual destructive mechanism that, in severe cases, can provoke the need for total knee substitution. As the disease progresses, various enzymatic, immunological, and inflammatory processes abnormally degrade hyaluronic acid (HA), SF's main component, and affect the concentrations of specific proteins, with the final results seriously endangering synovial fluid (SF)'s rheological and tribological features and characteristics. No effective treatments have been found to stop the progression of KOA, but the injection of HA-based viscoelastic gels has been considered (alone or combined with physiotherapy (PT)) as an alternative to symptomatic therapies. In order to evaluate the effect of viscosupplementation and PT on the characteristics of SF, SF aspirated from groups treated for KOA (HA Kombihylan® and groups that received Kombihylan® and complex PT) was analyzed and compared from analytical, spectrophotometrical, and rheological perspectives. In the patients treated with PT, the SF extracted 6 weeks after viscosupplementation had a superior elastic modulus (G') and viscous moduli (G″), as well as a homogeneous distribution of proteins and polysaccharides. The viscosupplementation fluid improved the bioadhesive properties of the SF, and the use of the viscosupplementation fluid in conjunction with PT was found to be favorable for the distribution of macromolecules and phospholipids, contributing to the lubrication process and the treatment of OA-affected joints.

Membrane-specific and calcium-dependent binding of the Arabidopsis C2 domain protein CaLB revealed by ATR-FTIR spectroscopy

C2 domain-containing proteins bind to cellular membranes and mediate diverse cellular processes. Although many of these membrane-interacting proteins have been identified, the molecular mechanisms of protein-membrane interactions and conformational dynamics are often poorly understood and remain to be investigated with appropriate methods. Here, we used attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and biomimetic membrane systems to analyse CalB, a yet uncharacterized Arabidopsis C2 domain protein. We studied membrane binding, lipid specificity and calcium dependency with solid-supported lipid membranes (SSLB) and small unilamellar lipid vesicles (SUVs). Membranes were composed of pure POPC lipids or of POPC/PI(3)P lipid mixtures. A significantly increased protein binding affinity was observed with membranes containing 1% PI(3)P indicating the high binding specificity of CaLB for PI(3)P. Furthermore, membrane binding occurs in a calcium-dependent manner with a higher calcium concentration increasing the binding of CaLB to the POPC/PI(3)P membrane. Secondary structure analysis of IR-spectra reveals that only minor conformational changes take place upon binding with a slight increase in the helical and disordered regions of CaLB.

Alginate-Based Carriers Loaded with Mulberry (Morus alba L.) Leaf Extract: A Promising Strategy for Prolonging 1-Deoxynojirimicyn (DNJ) Systemic Activity for the Nutraceutical Management of Hyperglycemic Conditions

The iminosugar 1-deoxynojirimicyn (DNJ) contained in mulberry leaves has displayed systemic beneficial effects against disorders of carbohydrate metabolism. Nevertheless, its effect is impaired by the short half-life. Alginate-based carriers were developed to encapsulate a DNJ-rich mulberry extract: Ca-alginate beads, obtained by external gelation, and spray-dried alginate microparticles (SDMs). Mean size and distribution, morphology, drug loading, encapsulation efficiency, experimental yield, and release characteristics were determined for the two formulations. Ca-alginate beads and SDMs exhibited an encapsulation efficiency of about 54% and 98%, respectively, and a DNJ loading in the range of 0.43-0.63 μg/mg. The in vitro release study demonstrated the carriers' capability in controlling the DNJ release in acid and basic conditions (<50% in 5 h), due to electrostatic interactions, which were demonstrated by 1H-NMR relaxometry studies. Thus, alginate-based particles proved to be promising strategies for producing food supplements containing mulberry leaf extracts for the management of hyperglycemic state.

On the Assessment of Strawberries' Shelf-Life and Quality, Based on Image Analysis, Physicochemical Methods, and Chemometrics

The aim of the present study was to evaluate Marisol strawberries' (Fragaria × ananassa) physicochemical quality and shelf-life during storage, using an integrated analytical approach. More specifically, the research aimed to assess the strawberries' color, texture, and nutritional quality, over an 11-day storage period, employing physicochemical analyses, spectrophotometric assays, Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy, image analysis, and statistical tools. The results revealed significant changes in the outer surface texture and color characteristics, indicating spoilage progression. Physicochemical parameters such as water activity, moisture content, soluble solids, titratable acidity, and ascorbic acid content exhibited significant alterations, influencing the taste profile and freshness perception. Antioxidant and antiradical activities showed fluctuations, suggesting a potential decrease in phenolic content during storage. Moreover, the ATR-FTIR spectra findings confirmed the results regarding the moisture content, soluble solids, and total phenolic content. The integration of physicochemical and image analysis-derived features through a principal component analysis (PCA) enabled the accurate classification of samples based on storage days. Regression analysis, using these features, successfully predicted the storage day with high accuracy. Overall, this integrated analytical approach provided valuable information on the estimation of Marisol strawberries' shelf-life and the prediction of their quality deterioration, contributing to better fruit management and the minimization of discards.

Mid-Infrared Spectroscopic Study of Cultivating Medicinal Fungi Ganoderma: Composition, Development, and Strain Variability of Basidiocarps

Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was proposed for rapid, versatile, and non-invasive screening of Ganoderma basidiocarps to assess their potential for specific applications. Fifteen species and strains of this fungus were selected for analysis, and fine sections at different parts of young and mature basidiocarps were obtained. The spectra of fungal samples showed significant differences interpreted in terms of biochemical composition using characteristic bands of proteins, polysaccharides, lipids, and triterpenoids. Obviously, for the transverse sections in trama, especially in the basal part, the most intense bands at 950-1200 cm-1 corresponded to polysaccharide vibrations, while for the superficial sections, the bands of carbonyl and aliphatic groups of triterpenoids at 1310-1470, 1550-1740, and 2850-2980 cm-1 predominated. The pilei, especially hymenium tubes, apparently contained more proteins than the bases and stipes, as evidenced by the intense bands of amide vibrations at 1648 and 1545-1550 cm-1. The specificity of the Ganoderma basidiocarp is a densely pigmented surface layer rich in triterpenoids, as proved by ATR-FTIR spectroscopy. The spectral differences corresponding to the specificity of the triterpenoid composition may indicate the prospects of individual strains and species of this genus for cultivation and further use in food, cosmetics, or medicine.

Sequential Extraction and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy Monitoring in the Biorefining of Brewer's Spent Grain

The brewing industry plays a significant role in producing a substantial annual volume of by-products, which contributes to the global accumulation of food waste. The primary by-product generated is brewer's spent grain (BSG), a lignocellulosic biomass rich in proteins, fiber, and moisture content. Leveraging biorefining and valorization techniques for BSG represents a promising strategy to enhance sustainability, resilience, and circularity within the brewing chain. To date, most studies have focused on extracting proteins from BSG. Yet, it is crucial to note that the fiber part of BSG also holds considerable potential for biorefining processes. This study introduces a novel sequential extraction method designed to integrally recover the major components of BSG. Notably, it introduces a reactive extraction approach that enables the simultaneous extraction and tuneable functionalization of the hemicellulose component. Additionally, the study assesses the utility of the attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy as a user-friendly tool to monitor and evaluate the effectiveness of the fractionation process. This spectroscopic technique can provide valuable insights into the changes and composition of BSG throughout the extraction process.

Application of spectrochemical analysis with chemometrics to profile biochemical alterations in nanoplastic-exposed HepG2 cells

Humans are routinely exposed to nanoplastics (NPs) in various ways, and this exposure presents a significant health risk. Nevertheless, there remain gaps in our knowledge, particularly in the mechanisms of toxicity of NPs with different surface charges at very low environmental concentrations. Herein, a spectrochemical approach was used to profile the cytotoxicity of NPs with different surface charges in HepG2 cells. It was found that all three NPs can cause some biomolecular alterations in cells, affecting cellular lipids, proteins, amino acids, and genetic material. Of these, PS and PS-COOH led to a non-linear dose-response, which may be related to a biphasic dose-response, whereas PS-NH2 led to a linear dose-response with a gradual increase in toxicity with increasing exposure concentration. In addition, the spectroscopic results showed that surface modifications led to cellular biochemical changes and caused adverse biological effects, with PS-NH2 exhibiting higher toxicity compared to PS or PS-COOH along with an inhibition of cell proliferation. Surprisingly PS-COOH, although considered the least toxic NP, appears to cause DNA damage. Overall, the toxic effects of different surface-modified NPs in cells were detected for the first time by applying spectrochemical techniques, and these findings provide important data towards understanding the emerging widespread environmental pollution of NPs and their effects on humans.

Rapid and non-destructive approach for characterization and differentiation of sealing wax using ATR-FTIR spectroscopy

Sealing wax is used for maintaining the integrity and authenticity of a document or physical evidence. Any tampering with the seal calls into question the overall integrity and authenticity of the tangible evidence or document. In these circumstances, determining the authenticity of the sealing material (physical and chemical) becomes imperative. In this study, ATR-FTIR spectroscopy supported by chemometrics has been used to differentiate sealing wax samples belonging to 12 different brands available across India. All the samples were first melted, cooled, and then analyzed using ATR-FTIR spectroscopy in the mid-infrared region (4000-600 cm-1 ). The obtained spectra were first examined visually for the presence of different functional groups. Principal component analysis (PCA) and principal component analysis-linear discriminant analysis (PCA-LDA) were employed to analyze the sample clustering patterns and to categorize them into their respective groups, respectively. For classification, a PCA-LDA training model was applied, and it demonstrated 95.83% accuracy. The validation test resulted in an accuracy of 83.33%. PCA-LDA model offered 100% accurate prediction for samples on various substrates, including cloth, cardboard, and paper. A blind study was also performed using five unknown samples, which were accurately classified into their respective groups. PCA-LDA model will be helpful in providing investigative leads by linking a questioned sealing wax sample with its respective group.

A comprehensive ATR-FTIR spectroscopic analysis for the identification and differentiation of lip balms

Lip balm may be encountered as physical evidence in cases involving sexual assaults, homicides, and kidnappings. Lip balm can be used as corroborative evidence by providing a potential link between the victim, accused, and the crime scene. For lip balms to be used as evidence, it is important to understand the diversity and their aging process under different conditions. Therefore, in this study, ATR-FTIR spectroscopy in conjunction with chemometric tools such as principal component analysis (PCA) and linear discriminant analysis (LDA) has been used for the objective identification and differentiation of 20 brands of lip balms. Moreover, lip balms on different substrates and wearing effects over time were also investigated. The results show that the PCA-LDA training accuracy was 92.5%, whereas the validation accuracy comes out to be 83.33%. A blind study using pristine samples was also performed which resulted in 80% PCA-LDA accuracy. PCA-LDA prediction of samples on various substrates showed a higher chemometric prediction accuracy for nonporous substrates (glass, plastic, and steel), than for porous substrates (cotton cloth, cotton swab stick, dry tissue paper, and white paper) for samples kept in room temperature and under sunlight for 15 days. The substrate study showed that the samples from various substrates could effectively generate respective spectra which can help in brand-level identification even after several days. The present method demonstrates a potential for lip balm samples to be used in forensic casework applications.

Extracorporeal membrane oxygenation and effects on tendon tissue: A vibrational spectroscopy study

Extracorporeal membrane oxygenation (ECMO) is an invasive medical technique used to provide life support in persons with insufficient cardiac and respiratory functionalities, or to preserve, postmortem, and organ function addressing organ/tissue transplant. Although a lot of information is available about organs in their entirety, the safety and effectiveness of allogeneic tissues collected from ECMO donors have not been fully elucidated. In this preliminary study, samples of tibial and peroneal human tendons were analyzed along their length with Raman microspectroscopy and attenuated total reflection-Fourier transform infrared micro-imaging. Both techniques evidenced a different chemical composition in the terminal with respect to the central part of the tendon. Thus, a differentiated analysis was performed depending on the specific position with respect to the bone or the muscle junctions. Spectroscopic analyses showed significant differences in the characteristics of the extracellular matrix between tendons from ECMO and non-ECMO donors, suggesting changes in the amino acid (proline and hydroxyproline) content and protein structure.

Point-of-Care Disease Screening in Primary Care Using Saliva: A Biospectroscopy Approach for Lung Cancer and Prostate Cancer

Saliva is a largely unexplored liquid biopsy that can be readily obtained noninvasively. Not dissimilar to blood plasma or serum, it contains a vast array of bioconstituents that may be associated with the absence or presence of a disease condition. Given its ease of access, the use of saliva is potentially ideal in a point-of-care screening or diagnostic test. Herein, we developed a swab "dip" test in saliva obtained from consenting patients participating in a lung cancer-screening programme being undertaken in north-west England. A total of 998 saliva samples (31 designated as lung-cancer positive and 17 as prostate-cancer positive) were taken in the order in which they entered the clinic (i.e., there was no selection of participants) during the course of this prospective screening programme. Samples (sterile Copan blue rayon swabs dipped in saliva) were analysed using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. In addition to unsupervised classification on resultant infrared (IR) spectra using principal component analysis (PCA), a range of feature selection/extraction algorithms were tested. Following preprocessing, the data were split between training (70% of samples, 22 lung-cancer positive versus 664 other) and test (30% of samples, 9 lung-cancer positive versus 284 other) sets. The training set was used for model construction and the test set was used for validation. The best model was the PCA-quadratic discriminant analysis (QDA) algorithm. This PCA-QDA model was built using 8 PCs (90.4% of explained variance) and resulted in 93% accuracy for training and 91% for testing, with clinical sensitivity at 100% and specificity at 91%. Additionally, for prostate cancer patients amongst the male cohort (n = 585), following preprocessing, the data were split between training (70% of samples, 12 prostate-cancer positive versus 399 other) and test (30% of samples, 5 prostate-cancer positive versus 171 other) sets. A PCA-QDA model, again the best model, was built using 5 PCs (84.2% of explained variance) and resulted in 97% accuracy for training and 93% for testing, with clinical sensitivity at 100% and specificity at 92%. These results point to a powerful new approach towards the capability to screen large cohorts of individuals in primary care settings for underlying malignant disease.

ATR-FTIR Spectroscopy with Chemometrics for Analysis of Saliva Samples Obtained in a Lung-Cancer-Screening Programme: Application of Swabs as a Paradigm for High Throughput in a Clinical Setting

There is an increasing need for inexpensive and rapid screening tests in point-of-care clinical oncology settings. Herein, we develop a swab "dip" test in saliva obtained from consenting patients participating in a lung-cancer-screening programme being undertaken in North West England. In a pilot study, a total of 211 saliva samples (n = 170 benign, 41 designated cancer-positive) were randomly taken during the course of this prospective lung-cancer-screening programme. The samples (sterile Copan blue rayon swabs dipped in saliva) were analysed using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. An exploratory analysis using principal component analysis (PCA,) with or without linear discriminant analysis (LDA), was then undertaken. Three pairwise comparisons were undertaken including: (1) benign vs. cancer following swab analysis; (2) benign vs. cancer following swab analysis with the subtraction of dry swab spectra; and (3) benign vs. cancer following swab analysis with the subtraction of wet swab spectra. Consistent and remarkably similar patterns of clustering for the benign control vs. cancer categories, irrespective of whether the swab plus saliva sample was analysed or whether there was a subtraction of wet or dry swab spectra, was observed. In each case, MANOVA demonstrated that this segregation of categories is highly significant. A k-NN (using three nearest neighbours) machine-learning algorithm also showed that the specificity (90%) and sensitivity (75%) are consistent for each pairwise comparison. In detailed analyses, the swab as a substrate did not alter the level of spectral discrimination between benign control vs. cancer saliva samples. These results demonstrate a novel swab "dip" test using saliva as a biofluid that is highly applicable to be rolled out into a larger lung-cancer-screening programme.

Analysis of thermally and UV-Vis aged plasticized PVC using UV-Vis, ATR-FTIR and Raman spectroscopy

The stability of plasticized poly (vinyl chloride) (PVC-P) stored under indoor conditions, despite it being in commercial use for more than 80 years, hasn't been sufficiently experimentally examined, as documented in available works on PVC-P stability. With the increasing number of actively deteriorating priceless modern and contemporary artworks made of PVC-P, there is a growing need for studies dealing with the analysis of changing characteristics of PVC-P during its aging under indoor conditions. This work addresses these issues by designing PVC-P formulations, drawing on the available information on technology of PVC production and PVC compounding from the last century, and analyzing the changes in the characteristic properties of model samples made from the designed PVC-P formulations exposed to accelerated UV-Vis and thermal aging using UV-Vis, ATR-FTIR and Raman spectroscopy. The results of our study further expand the knowledge regarding the stability of PVC-P and the benefits of using non-destructive, non-invasive spectroscopic methods of analysis for monitoring changes in PVC-P characteristic properties induced by aging.

Adsorption of glycine at the anatase TiO2/water interface: Effects of Ca2+ ions

Adsorption reactions of amino acids (AAs) on TiO₂ nanoparticles (NPs) play an important role in the available nutrients in soils and sediments. The pH effects on glycine adsorption have been studied, but little is known about its coadsorption with Ca²⁺ at the molecular level. Combined attenuated total reflectance Fourier transform infrared (ATR-FTIR) flow-cell measurements and density functional theory (DFT) calculations were used to determine the surface complex and corresponding dynamic adsorption/desorption processes. The structures of glycine adsorbed onto TiO₂ were closely associated with its dissolved species in the solution phase. The presence of Ca²⁺ exerted different influences on glycine adsorption within pH 4-11, thus affecting its migration rate in soils and sediments. The mononuclear bidentate complex at pH 4-7, involving the COO^- moiety of zwitterionic glycine, remained unchanged in the absence and presence of Ca²⁺. At pH 11, the mononuclear bidentate complex with deprotonated NH₂ can be removed from the TiO₂ surface upon coadsorption with Ca²⁺. The bonding strength of glycine on TiO₂ was much weaker than that of the Ca-bridged ternary surface complexation. Glycine adsorption was inhibited at pH 4 but was enhanced at pH 7 and 11.

Calcium-induced compaction and clustering of vesicles tracked with molecular resolution

Theory and simulations predict the complex nature of calcium interaction with the lipid membrane. By maintaining the calcium concentrations at physiological conditions, herein we demonstrate experimentally the effect of Ca²⁺ in a minimalistic cell-like model. For this purpose, giant unilamellar vesicles (GUVs) with a neutral lipid DOPC are generated and the ion-lipid interaction is observed with attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy providing molecular resolution. Firstly, Ca²⁺ encapsulated within the vesicle binds to the phosphate head groups of the inner-leaflets and triggers vesicle compaction. This is tracked by changes in vibrational modes of the lipid groups. As the calcium concentration within the GUV increases, IR intensities change indicating vesicle dehydration and lateral compression of the membrane. Secondly, by inducing a calcium gradient across the membrane up to a ratio of 1:20, interaction between several vesicles occur as Ca²⁺ can bind to the outer-leaflets leading to vesicle clustering. It is observed that larger calcium gradients induce stronger interactions. These findings with an exemplary biomimetic model reveal that divalent calcium ions not only cause local changes to the lipid packing, but also have macroscopic implications to initiate vesicle-vesicle interaction.

Monitoring the curing efficiency of a plant-based green engineered additive on caprine skin: a spectroscopic and chemometric novel approach

Environmental sustainability in industrial processing is one of the most fundamental requirements for sustainable development. The leather industry is known for its vast environmental pollution. But, green engineering may occur a paradigm shift in this sector. Plant-based goatskins curing is a cutting-edge green technology that holds the concept of pollution reduction through prevention on the upper stream of leather processing. The successful and rapid monitoring of the efficiency of this technology is the foremost demand for mass-level applications. In this study, ATR-FTIR spectroscopy was employed to monitor this technology's efficiency using a plant Polygonum hydropiper. Chemometrics was also applied to extract information from spectral data leading to an understanding of the inherent effect of studying preservatives on goatskins collagen chemistry. 10% plant-paste +5% NaCl, 10% plant-paste +10% NaCl, and 15% plant-paste +5% NaCl on goatskin were assessed by ATR-FTIR on 0th, 10th, and 30th days of preservation. The Spectral peak fitting (R² = 0.99) area of amide I and II of collagen peptide bands revealed 2.73 to 1.33 times more structural suitability of studied goatskins than the control. Principal component analysis and Hierarchical cluster analysis showed that, after 30 days of curing, 15% paste +5% salt-rubbed goatskin collagen matrix significantly (around 50%) interacted with P. hydropiper. The interaction was superficial, as it happened before the opening up of collagen fibers. In conclusion, ATR-FTIR spectroscopy with Chemometrics can be an effective tool in evaluating the efficiency of goatskin curing and understanding the entire effect on collagen chemistry quickly.

Detection of metabolic syndrome with ATR-FTIR spectroscopy and chemometrics in blood plasma

Metabolic Syndrome (MetS) is a constellation of 3 or more risk factor (abdominal obesity, high triglycerides, low HDL-c, high blood pressure, and elevated blood glucose) for atherosclerotic cardiovascular disease. Considering these systemic metabolic changes in the biochemical pathways of all biomolecules, Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy is a rapid, low-cost, and reagent-free alternative technique capable of identifying spectral biomarkers that differentiate subjects with MetS from control. In this study, plasma samples from 74 subjects (14 MetS, 60 control) were analyzed on the ATR-FTIR spectrophotometer. The objective was to differentiate subjects with MetS from control with supervised chemometrics modeling (Orthogonal Partial Least Squares-Discriminant Analysis, OPLS-DA). Additionally, the inflammatory status of subjects with MetS and control (supervised by C-reactive protein - CRP, leptin, and cell-free DNA - cfDNA) was verified. The OPLS-DA model achieved 100% sensitivity and specificity in cross-validation. For 1 latent variable (93.4% of variance), RMSECV < 0.002, PRESS CV < 0.0001, and R² > 0.9999 was obtained. Significant spectrochemical differences (p < 0.05) were found between MetS and control subjects in the following biomolecular regions (cm^-1): 1717-1703 [ν(CO) and δ(NH)], 1166-1137 [ν(C-OH) + ν(CO) and ν(CC) + δ(OH) + ν(CO)], 1113-1040 [ν(PO₂^-) and ν(C-OH)], and 1027-1008 [ν(CO) and v(CH₂OH)]. In the OPLS-DA model loadings, amide I [1720-1600 cm^-1, ν(CO)] and amide II [1570-1480 cm^-1, δ(NH) + ν(CH)] had significantly greater weight than all other regions. There was a significant difference in inflammatory status between MetS patient and control (p < 0.05 for CRP and leptin, and p < 0.01 for cfDNA).

The recovery effect of Vitamin C on structural alterations due to Streptozotocin-Induced diabetes in rat testicular tissues

Type I Diabetes is a multisystem disease that causes alterations in carbohydrate, protein, and fat metabolisms due to hyperglycemia. It has an extensive pathology, especially the mechanism involving oxidative stress is still complex. Type I diabetes is correlated with increased formation of free radicals and decreased levels of antioxidant potential. Vitamin C (Vit C) is a powerful antioxidant that participates in antioxidant defense, protecting lipid membranes and proteins from oxidative damage by donating electrons to free radicals. The effect of type I diabetes and the recovery role of Vit C on the structure and composition of the biomolecular content of testicular tissue is still unknown. Therefore, the current study aimed to investigate the alterations in the biomolecules of rat testes due to Streptozotocin (STZ)-induced type I diabetes using Attenuated Total Reflectance (ATR)-Fourier Transform Infrared (FTIR) spectroscopy and histological staining. The results revealed that the biomolecular structure and composition of testicular tissue are highly affected due to the development of diabetes. We obtained decreased saturation levels and increased unsaturation index in the lipids indicating the presence of lipid peroxidation in the diabetic state. The elevated lipid peroxidation levels have been implicated in the pathogenesis of naturally occurring and chemically induced diabetes. On the other hand, the protein content of diabetic rat testicular tissue was shown to decrease considerably, indicating an increase in proteolysis processes. Supporting the ratio of protein structural and conformational change, protein secondary structural components were also found to alter substantially in the diabetic state. Diabetes was also shown to lead to a decrease in the content of nucleic acids compared to proteins. These diabetes-induced alterations were found to be substantially recovered with the administration of Vit C. Although different doses and administration types of Vit C have been reported in the literature, there is no consensus yet. Therefore, we used three different doses of Vit C in our study as high (100 mg/kg/day), medium (50 mg/kg/day) and low (15 mg/kg/day) doses intraperitoneally in the present study, and the medium dose was found to be the most effective in the recovery from the diabetes-induced structural damages on rat testicular tissue. Vit C may have a therapeutic effect to be used as a complementary therapy in the treatment of diabetes.

ATR-FTIR spectrum analysis of plasma samples for rapid identification of recovered COVID-19 individuals

The development of fast, cheap and reliable methods to determine seroconversion against infectious agents is of great practical importance. In the context of the COVID-19 pandemic, an important issue is to study the rate of formation of the immune layer in the population of different regions, as well as the study of the formation of post-vaccination immunity in individuals after vaccination. Currently, the main method for this kind of research is enzyme immunoassay (ELISA, enzyme-linked immunosorbent assay). This technique is sufficiently sensitive and specific, but it requires significant time and material costs. We investigated the applicability of attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy associated with machine learning in blood plasma to detect seroconversion against SARS-CoV-2. The study included samples of 60 patients. Clear spectral differences in plasma samples from recovered COVID-19 patients and conditionally healthy donors were identified using multivariate and statistical analysis. The results showed that ATR-FTIR spectroscopy, combined with principal components analysis (PCA) and linear discriminant analysis (LDA) or artificial neural network (ANN), made it possible to efficiently identify specimens from recovered COVID-19 patients. We built classification models based on PCA associated with LDA and ANN. Our analysis led to 87% accuracy for PCA-LDA model and 91% accuracy for ANN, respectively. Based on this proof-of-concept study, we believe this method could offer a simple, label-free, cost-effective tool for detecting seroconversion against SARS-CoV-2. This approach could be used as an alternative to ELISA.

Study of the Long-Term Aging of Polypropylene-Made Disposable Surgical Masks and Filtering Facepiece Respirators

The main purpose of this work is to contribute to understanding the mechanism of oxidation of the polymeric components of common disposable masks used during the COVID-19 pandemic to offer the chemical basis to understand their long-term behavior under typical environmental conditions. Artificial aging of representative mask layers under isothermal conditions (110 °C) or accelerated photoaging showed that all the PP-made components underwent a fast oxidation process, following the typical hydrocarbon oxidation mechanism. In particular, yellowing and the melting temperature drop are early indicators of their diffusion-limited oxidation. Morphology changes also induced a loss of mechanical properties, observable as embrittlement of the fabric fibers. Results were validated through preliminary outdoor aging of masks, which allows us to predict they will suffer fast and extensive oxidation only in the case of contemporary exposure to sunlight and relatively high environmental temperature, leading to their extensive breakdown in the form of microfiber fragments, i.e., microplastics.

Rapid and nondestructive analysis of lipstick on different substrates using ATR-FTIR spectroscopy and chemometrics

Lipstick can be an important piece of evidence in crimes like murders, rapes, and suicides. Due to its prevalence, it can be an important corroborative evidence in crime reconstruction. The analysis of such evidence can provide an evidentiary link between the suspect, the victim, object, or the crime scene. We report the use of nondestructive ATR-FTIR spectroscopy combined with chemometrics for the classification of 10 brands of lipsticks with nine samples each. Chemometric method of partial least square-discriminant analysis (PLS-DA) has been employed to interpret the data and classify the samples into their respective classes. The PLS-DA model provides an AUC figure above 0.99 in all brands except one; for which it is slightly less at 0.94. We have also tested the traces of these lipstick samples on different substrates treating them as unknowns in the already trained PLS-DA model. 100% of the samples on nine substrates viz. a cotton, nylon, plastic, dry tissue, denim (blue jeans), wet tissue, nitrile gloves, white paper, and polyester were correctly attributed to their source brand. In conclusion, the results suggest that ATR-FTIR combined with the chemometrics is a rapid, nondestructive, and accurate method for the discrimination and source attribution of lipstick. This study has potential for use in actual forensic casework conditions.

Impaired Extracellular Proteostasis in Patients with Heart Failure

BACKGROUND

Proteostasis impairment and the consequent increase of amyloid burden in the myocardium have been associated with heart failure (HF) development and poor prognosis. A better knowledge of the protein aggregation process in biofluids could assist the development and monitoring of tailored interventions.

AIM

To compare the proteostasis status and protein's secondary structures in plasma samples of patients with HF with preserved ejection fraction (HFpEF), patients with HF with reduced ejection fraction (HFrEF), and age-matched individuals.

METHODS

A total of 42 participants were enrolled in 3 groups: 14 patients with HFpEF, 14 patients with HFrEF, and 14 age-matched individuals. Proteostasis-related markers were analyzed by immunoblotting techniques. Fourier Transform Infrared (FTIR) Spectroscopy in Attenuated Total Reflectance (ATR) was applied to assess changes in the protein's conformational profile.

RESULTS

Patients with HFrEF showed an elevated concentration of oligomeric proteic species and reduced clusterin levels. ATR-FTIR spectroscopy coupled with multivariate analysis allowed the discrimination of HF patients from age-matched individuals in the protein amide I absorption region (1700-1600 cm^-1), reflecting changes in protein conformation, with a sensitivity of 73 and a specificity of 81%. Further analysis of FTIR spectra showed significantly reduced random coils levels in both HF phenotypes. Also, compared to the age-matched group, the levels of structures related to fibril formation were significantly increased in patients with HFrEF, whereas the β-turns were significantly increased in patients with HFpEF.

CONCLUSION

Both HF phenotypes showed a compromised extracellular proteostasis and different protein conformational changes, suggesting a less efficient protein quality control system.

Mock-Ups in Plastic Conservation Research: Processing and Aging of 3D Celluloid Specimens Simulating Historical Objects

The preparation of mock-ups in heritage science studies represents a valid alternative for investigation purposes, avoiding extensive sampling of cultural heritage objects. This work presents for the first time the successful preparation of three dimensional (3D) mock-ups made of celluloid, considering a combination of historical industrial production strategies and small-scale lab facilities. Prefabricated transparent celluloid sheets were acquired and then shaped through compression molding for creating mock-ups with 3D geometries. These reflected common and representative shapes encountered in the collection of the Deutsches Museum. Visual inspection of the mock-ups allowed determining the best compression molding conditions. Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) confirmed the absence of molecular heterogeneity due to the processing method. Artificial aging of the mock-ups was conducted to reach degradation states comparable with naturally aged objects. ATR-FTIR investigation offered first insights into the induced artificial degradation. Ion chromatography (IC) and gel permeation chromatography (GPC) analyses allowed to assess the extent of the artificial aging of the celluloid mock-ups and confirmed the occurrence of loss of camphor, denitration, and main chain polymer scission, the latter being the predominant decay path. The comparison with historical objects highlighted that the mock-ups are representative of moderately aged artifacts. As such, this study paves the way for implementing moderately aged celluloid 3D mock-ups in heritage science research, enabling in-depth testing for the scope of conservation.

Impact of Metal Nanoparticles on the Phytochemical and Antioxidative Properties of Rapeseed Oil

The agricultural uses of nanoparticles continue to be considered as innovative methods that require more in-depth research into their impact on product quality. In our study, we investigated the effects of fertilizers containing metal nanoparticles (silver AgNPs and copper CuNPs) during the plant growth stage of winter rape cultivation, and in most experimental variants, with the exception of the (x2) application of AgNPs, we observed a decrease in the mass of one thousand seeds (MTS). The obtained result was 11.55% higher relative to the control sample in 2019, and also increased after the (x1) 4.36% and (x2) 11.11% application of CuNPS in 2020. The analyzed oxidative stability of the oil increased in both experimental years (2019-2020), with the highest values recorded after the (x1) and (x2) application of CuNPS-4.94% and 8.31%, respectively, in the first year of cultivation, and after the (x2) application of CuNPS-12.07% in the subsequent year. It was also observed that the content of polyphenols, flavonoids, squalene, tocopherols α and δ, chlorophylls, and carotenoids increased in the oil. Moreover, spectral FTIR analysis was performed on the oil samples obtained from cultivations sprayed with solutions containing Ag or Cu nanoparticles and revealed changes in several spectral regions with the maxima at ~1740, 1370, 1230, and ~1090 cm^-1. Additionally, a FTIR analysis conducted in combination with multivariate analysis allowed us to classify the studied oils into the most similar groups and to study the structure of data variability. The conducted analyses revealed that the use of nanoparticles resulted in decreased size of the produced seeds and improved antioxidative properties of rapeseed oil.

Effect of Antibiotic Amphotericin B Combinations with Selected 1,3,4-Thiadiazole Derivatives on RPTECs in an In Vitro Model

4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol (C1) and 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl] benzene1,3-diol (NTBD) are representative derivatives of the thiadiazole group, with a high antimycotic potential and minimal toxicity against normal human fibroblast cells. The present study has proved its ability to synergize with the antifungal activity of AmB. The aim of this work was to evaluate the cytotoxic effects of C1 or NTBD, alone or in combination with AmB, on human renal proximal tubule epithelial cells (RPTECs) in vitro. Cell viability was assessed with the MTT assay. Flow cytometry and spectrofluorimetric techniques were used to assess the type of cell death and production of reactive oxygen species (ROS), respectively. The ELISA assay was performed to measure the caspase-2, -3, and -9 activity. ATR-FTIR spectroscopy was used to evaluate biomolecular changes in RPTECs induced by the tested formulas. The combinations of C1/NTBD and AmB did not exert a strong inhibitory effect on the viability/growth of kidney cells, as evidenced by the negligible changes in the apoptotic/necrotic rate and caspase activity, compared to the control cells. Both NTBD and C1 displayed stronger anti-oxidant activity when combined with AmB. The relatively low nephrotoxicity of the thiadiazole derivative combinations and the protective activity against AmB-induced oxidative stress may indicate their potential use in the therapy of fungal infections.

Micro-plastics in the Vicinity of an Urban Solid Waste Management Facility in India: Assessment and Policy Implications

The study focuses on analyzing the presence and quantity of microplastics near an unscientific solid waste dumping site located at Kochi city in India and thereby assessing the contribution of massive open dumping towards microplastic pollution in the river. Two sets of sampling with three sediment samples from nearby Kadambrayar river and five topsoil samples from various parts of the Brahmapuram waste dumping yard were carried out during January - February 2019. The samples were analyzed as per the US National Oceanic and Atmospheric Administration (US NOAA) protocol. ATR-FTIR and DSC analysis based characterization indicated that polyethylene dominated the micro plastics followed by polypropylene and polystyrene. The size distribution of particles showed that comparatively larger particles of size range between 2.36 - 4.75 mm were present in the topsoil than that in river sediments which had more number of particles in size range below 2.36 mm. The study confirmed the presence of an average of 100 microplastic pieces per 100 gram of sediments of Kadambrayar river bordering the waste dumping yard at Brahmapuram. The topsoil of Brahmapuram waste dumping yard was found to contain 178 pieces of microplastics per 100 gm of soil. Microplastics are found to be high in the river stretch near the open dumping site which has a significant role in the pollution, causing a major threat to the entire ecosystem.

Exploring the Potential of Grape Pomace Extract to Inhibit Thermo-Oxidative Degradation of Sunflower Oil: From Routine Tests to ATR-FTIR Spectroscopy

Exploring new sources of natural antioxidants is of great interest to edible oil producers, in line with the toxicological problems generated by the use of synthetic antioxidants. This study assesses the potential of lyophilized Pinot Noir grape pomace extract (GPE) to enhance the sunflower oil stability against thermo-oxidative damage compared to BHT during a prolonged exposure to convective heat at 185 °C. Oil thermo-oxidation was monitored based on specific indices such as peroxide value (PV), para-anisidine value (p-AV), inhibition of oil oxidation (IO), total oxidation (TOTOX) value, conjugated dienes and trienes (CDs, CTs), but also by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), where absorbance ratios A 3009 cm^-1/A 2922 cm^-1 (RI), A 3009 cm^-1/A 2853 cm^-1 (RII), A 3009 cm^-1/A 1744 cm^-1 (RIII) and RIV = A 1744 cm^-1/A 2922 cm^-1 (RIV) were investigated. GPE showed a significant inhibitory effect on oil thermo-oxidation and this response was concentration-dependent. Substantial decreases in the investigated indices, compared to the control without added antioxidants, were obtained after 4 h and 8 h of heat exposure of the 800 ppm GPE sample: PV (47%; 42%), p-AV (38%; 33%), IO (54%; 46%), TOTOX (41%; 37%), CDs (46%; 39%), CTs (44%; 29%). Oil exposure to heat resulted in changes in RI-RIV attributed to the reduction in the degree of unsaturation, in response to primary and secondary lipid oxidation. FTIR spectroscopy can be used to differentiate untreated and heat-treated oils based on the absorbance ratios. An inhibitory effect close to that of BHT was achieved by 500 ppm GPE, while a dose of 800 ppm provided greater protection against thermo-oxidation. Our results promote GPE as a natural additive to limit the thermo-oxidative damage of plant oils.

Fast and Noninvasive Hair Test for Preliminary Diagnosis of Mood Disorders

The main objective of this study was to develop a test for the fast and noninvasive prediagnosis of mood disorders based on the noninvasive analysis of hair samples. The database included 75 control subjects (who were not diagnosed with depression) and 40 patients diagnosed with mood disorders such as depression or bipolar disorder. Both women and men, aged 18-65 years, participated in the research. After taking the hair samples, they were washed (methanol-water-methanol by shaking in a centrifuge for two min) and air-dried in a fume hood. Each hair collection was analyzed using Fourier transform infrared spectroscopy attenuated total reflection (ATR-FTIR) spectroscopy. Subsequently, the results obtained were analyzed based on chemometric methods: hierarchical cluster analysis (HCA) and principal component analysis (PCA). As a results of the research conducted, potential differences were noticed. There was a visible change in the spectra intensity at around 2800-3100 cm^-1 and smaller differences around 1460 cm^-1; the bands can be assigned to protein vibrations. However, these are preliminary studies that provide a good basis for the development of a test for the initial diagnosis of mood disorders.

Rapid diagnosis of malignant pleural mesothelioma and its discrimination from lung cancer and benign exudative effusions using blood serum

Malignant pleural mesothelioma (MPM), an aggressive cancer associated with exposure to fibrous minerals, can only be diagnosed in the advanced stage because its early symptoms are also connected with other respiratory diseases. Hence, understanding the molecular mechanism and the discrimination of MPM from other lung diseases at an early stage is important to apply effective treatment strategies and for the increase in survival rate. This study aims to develop a new approach for characterization and diagnosis of MPM among lung diseases from serum by Fourier transform infrared spectroscopy (FTIR) coupled with multivariate analysis. The detailed spectral characterization studies indicated the changes in lipid biosynthesis and nucleic acids levels in the malignant serum samples. Furthermore, the results showed that healthy, benign exudative effusion, lung cancer, and MPM groups were successfully separated from each other by applying principal component analysis (PCA), support vector machine (SVM), and especially linear discriminant analysis (LDA) to infrared spectra.

New Heterotrinuclear CuIILnIIICuII (Ln = Ho, Er) Compounds with the Schiff Base: Syntheses, Structural Characterization, Thermal and Magnetic Properties

New heterotrinuclear complexes with the general formula [Cu₂Ln(H₂L)(HL)(NO₃)₂]·MeOH (Ln = Ho (1), Er (2), H₄L = N,N′-bis(2,3-dihydroxybenzylidene)-1,3-diaminopropane) were synthesized using compartmental Schiff base ligand in conjugation with auxiliary ligands. The compounds were characterized by elemental analysis, ATR-FTIR spectroscopy, X-ray diffraction, TG, DSC, TG-FTIR and XRD analysis. The N₂O₄ salen-type ligand coordinates 3d and 4f metal centers via azomethine nitrogen and phenoxo oxygen atoms, respectively, to form heteropolynuclear complexes having CuO₂Ln cores. In the crystals 1 and 2, two terminal Cu(II) ions are penta-coordinated with a distorted square-pyramidal geometry and a Ln^III ion with trigonal dodecahedral geometry is coordinated by eight oxygen atoms from [Cu^II(H₂L)(NO₃)]⁻ and [Cu^II(HL)(NO₃)]²⁻ units. Compounds 1 and 2 are stable at room temperature. During heating, they decompose in a similar way. In the first decomposition step, they lose solvent molecules. The exothermic decomposition of ligands is connected with emission large amounts of gaseous products e.g., water, nitric oxides, carbon dioxide, carbon monoxide. The final solid products of decomposition 1 and 2 in air are mixtures of CuO and Ho₂O₃/Er₂O₃. The measurements of magnetic susceptibilities and field dependent magnetization indicate the ferromagnetic interaction between Cu^II and Ho^III ions 1.

Genetic algorithm based artificial neural network and partial least squares regression methods to predict of breakdown voltage for transformer oils samples in power industry using ATR-FTIR spectroscopy

The current study proposes a novel analytical method for calculating the breakdown voltage (BV) of transformer oil samples considered as a significant method to assess the safe operation of power industry. Transformer oil samples can be analyzed using the Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy combined with multivariate calibration methods. The partial least squares regression (PLSR) back propagation-artificial neural network (BP-ANN) methods and a genetic algorithm (GA) for variable selection are used to predict and assess breakdown voltage in transformer oil samples from various Iranian transformer oils. As a result, the root mean square error (RMSE) and correlation coefficient for the training and test sets of oil samples are also calculated. In the GA-PLS-R method, the squared correlation coefficient (R²pred) and root mean square prediction error (RMSEP) are 0.9437 and 2.6835, respectively. GA-BP-ANN, on the other hand, had a lower RMSEP value (0.2874) and a higher R²pred function (0.9891). Considering the complexity of transformer oil samples, the performance of GA-BP-ANN has resulted in an efficient approach for predicting breakdown voltage; consequently, it can be effectively used as a new method for quantitative breakdown voltage analysis of samples to evaluate the health of transformer oil. .

Non/mini-invasive monitoring of diabetes-induced myocardial damage by Fourier transform infrared spectroscopy: Evidence from biofluids

Early identification of diabetic cardiomyopathy (DCM) can help clinicians develop targeted treatment plans and forensic pathologists make accurate postmortem diagnoses. In the present study, diabetes-induced metabolic abnormalities in the myocardium and biofluids (plasma, urine, and saliva) of db/db mice of various ages (7, 12, and 21 weeks) were investigated by attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopy. The results indicated that the diabetic and control groups had significantly different changes in the function groups of lipids, phosphate macromolecules (mostly nucleic acids), protein compositions and conformations, and carbohydrates (primarily glucose) in the myocardium and biofluids. The prediction model for quantifying DCM severity was developed on db/db mice's myocardial spectra using a genetic algorithm (GA)-partial least squares (PLS) regression method. Following that, the linear correlations between the predicted values for DCM severity and spectra for db/db biofluids were evaluated using the GA-PLS regression algorithm. The results showed there were good linear correlations between the predicted values for DCM severity and spectra for plasma (R² = 0.929), saliva (R² = 0.967), urine (R² = 0.954), and combination of plasma and saliva (R² = 0.980). This study provides a novel perspective on detecting diabetes-related biofluid and cardiac metabolic abnormalities and demonstrates the potential of biofluid infrared spectro-diagnostic models for non/mini-invasive assessment of DCM.

Investigations of pH-dependent dynamic properties of OmpG-16SL, an outer membrane protein G mutant by ATR-FTIR spectroscopy

In this paper, the dynamic properties of outer membrane protein G mutant (OmpG-16SL) are investigated with ATR-FTIR spectroscopy. While OmpG-WT has 14 β-strands in its structure, the mutant is designed to have 16 β-strands with the intention of creating an enlarged pore. Loop L6 is elongated by introducing six residues, two of which are negatively charged. The solvent accessibility of the OmpG-16SL mutant is compared with WT and a previously reported mutant OmpG-16S by tracking the ¹H/²H exchange kinetics in acidic and neutral buffer conditions. The exchange kinetics and dynamics in the fast and slow exchange phases are separately investigated using the 2DCOS technique, which enables the tracking of the structural changes at each phase of the exchange process. The results suggest that the mutant OmpG-16SL is equally exposed to buffer in both acidic and neutral pH conditions. Additionally, the time range in the fast phase is very short - one-tenth of that for WT - and most of the exchange is completed in this phase. This fast exchange within minutes is also indicative of the presence of highly flexible and/or unstructured regions. In all, the fast exchange rates independent of the buffer pH justify the assumption that there is an altered interaction among the charged residues, which leads to a steadily-open pore. The role of the side-chain interactions within the pore and between the loops involving the loop L6 is also discussed.

Effect of Sunlight on the Change in Color of Unsteamed and Steamed Beech Wood with Water Steam

This paper presents the differences in the color changes of unsteamed and steamed beech wood (Fagus sylvatica L.) caused by long-term exposure to sunlight on the surface of wood in interiors for 36 months. The light white-gray color of the yellow tinge of native beech wood darkened under the influence of sunlight, and the wood took on a pale brown color of yellow tinge. The degree of darkening and browning is quantified by the value of the total color difference ∆E* = 13.0. The deep brown-red color of steamed beech under the influence of sunlight during the exposure brightened, and the surface of the wood took on a pale brown hue. The degree of lightening of the color of steamed beech wood in the color space CIE L*a*b* is quantified by the value of the total color difference ∆E* = 7.1. A comparison of the color changes of unsteamed and steamed beech wood through the total color difference ∆E* due to daylight shows that the surface of steamed beech wood shows 52.2% smaller changes than unsteamed beech wood. The lower value of the total color difference of steamed beech wood indicates the fact that steaming of beech wood with saturated water steam has a positive effect on the color stability and partial resistance of steamed beech wood to the initiation of photochemical reactions induced by UV-VIS wavelengths of solar radiation. Spectra ATR-FTIR analyses declare the influence of UV-VIS components of solar radiation on unsteamed and steamed beech wood and confirm the higher color stability of steamed beech wood.

Haemoprocessor: A Portable Platform Using Rapid Acoustically Driven Plasma Separation Validated by Infrared Spectroscopy for Point-of-Care Diagnostics

The identification of biomarkers from blood plasma is at the heart of many diagnostic tests. These tests often need to be conducted frequently and quickly, but the logistics of sample collection and processing not only delays the test result, but also puts a strain on the healthcare system due to the sheer volume of tests that need to be performed. The advent of microfluidics has made the processing of samples quick and reliable, with little or no skill required on the user's part. However, while several microfluidic devices have been demonstrated for plasma separation, none of them have validated the chemical integrity of the sample post-process. Here, we present Haemoprocessor: a portable, robust, open-fluidic system that utilizes Travelling Surface Acoustic Waves (TSAW) with the expression of overtones to separate plasma from 20× diluted human blood within a span of 2 min to achieve 98% RBC removal. The plasma and red blood cell separation quality/integrity was validated through Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy and multivariate analyses to ascertain device performance and reproducibility when compared to centrifugation (the prevailing gold-standard for plasma separation). Principal Component Analysis (PCA) showed a remarkable separation of 92.21% between RBCs and plasma components obtained through both centrifugation and Haemoprocessor methods. Moreover, a close association between plasma isolates acquired by both approaches in PCA validated the potential of the proposed system as an eminent cell enrichment and plasma separation platform. Thus, compared to contemporary acoustic devices, this system combines the ease of operation, low sample requirement of an open system, the versatility of a SAW device using harmonics, and portability.

Adsorption of serine at the anatase TiO2/water interface: A combined ATR-FTIR and DFT study

Knowledge of the adsorption reactions between serine and minerals is critical to understanding the geochemical processes of amino acids (i.e., mobility, bioavailability, and degradation) in the environment. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) flow-cell measurements were used to distinguish the inner- and outer-sphere complexation and reveal the dynamic adsorption and desorption processes of each surface complex at the molecular level. Density functional theory (DFT) calculations were applied to determine the structures of the surface complexes and to justify the peak assignments of the serine dissolved in solution and adsorbed on TiO₂. The structures of interfacial serine were governed by pH conditions but were not affected by the changes in adsorption time and serine concentration. The ATR-FTIR spectra and the results of DFT calculations resolved two different bidentate inner-sphere coordination, involving the COO^- group of the serine zwitterion at pH 4-8 and the serine anion at pH 10. The dynamic adsorption processes of these two surface complexes conformed to the pseudo-second-order kinetic model. The stable inner-sphere complexation could not be entirely removed from the TiO₂ surface upon serine desorption. In addition to reducing the migration rate in the environment, the bidentate inner-sphere coordination contributes to the potential degradation of the serine NH₃⁺ and NH₂ groups. Our research provides new insights into serine adsorption and desorption, facilitating further understanding of the fate and transport of amino acids in the environment.

Discrimination of electrical tapes using ATR-FTIR spectroscopy and chemometrics

Electrical tapes are recovered during criminal investigations as physical evidence in cases of rape, kidnapping, and explosion incidents. The analysis of such evidence can provide an evidentiary link between the suspect, the victim, object, or the crime scene. In the present study, 25 brands of electrical tapes have been analyzed using ATR-FTIR (attenuated total reflectance Fourier transform infrared) spectroscopy. Samples (1 cm² ) were analyzed in the mid IR (Infrared) region from 4000-600 cm^-1 , and the functional groups of various components have been profiled. Chemometric methods-PCA (principal component analysis) and PCA-LDA (linear discriminant analysis) have been employed to interpret the data and classify the samples into its respective classes. Preliminary assessment of sample clustering due to similar chemical composition was visualized using PCA. PCA-LDA applied for classification purpose yielded classification accuracy (calibration) of 92.98% for the adhesive side and 88% for the backing side. The validation results showed classification accuracy of 89.47% for the adhesive side and 84% for the backing side. Blind validation study was carried out using 5 samples, and classification accuracy of 100% and 80% was obtained for the adhesive and the backing side, respectively. In the current study, a preliminary substrate study was carried out, and the results showed that the backing samples could be more accurately matched to their correct source of origin than the adhesive side.

Influence of UV Radiation on the Color Change of the Surface of Steamed Maple Wood with Saturated Water Steam

The wood of maple (Acer Pseudopatanus L.) was steamed with a saturated steam-air mixture at a temperature of t = 95 °C or saturated steam at t = 115 °C and t = 135 °C, in order to give a pale pink-brown, pale brown, and brown-red color. Subsequently, samples of unsteamed and steamed maple wood were irradiated with a UV lamp in a Xenotest Q-SUN Xe-3-H after drying, in order to test the color stability of steamed maple wood. The color change of the wood surface was evaluated by means of measured values on the coordinates of the color space CIE L* a* b*. The results show that the surface of unsteamed maple wood changes color markedly under the influence of UV radiation than the surface of steamed maple wood. The greater the darkening and browning color of the maple wood by steaming, the smaller the changes in the values at the coordinates L*, a*, b* of the steamed maple wood caused by UV radiation. The positive effect of steaming on UV resistance is evidenced by the decrease in the overall color difference ∆E*. While the value of the total color diffusion of unsteamed maple wood induced by UV radiation is ∆E* = 18.5, for maple wood steamed with a saturated steam-air mixture at temperature t = 95 °C the ∆E* decreases to 12.6, for steamed maple wood with saturated water steam with temperature t = 115 °C the ∆E* decreases to 10.4, and for saturated water steam with temperature t = 135 °C the ∆E* decreases to 7.2. Differential ATR-FTIR spectra declare the effect of UV radiation on unsteamed and steamed maple wood and confirm the higher color stability of steamed maple wood.

A rapid quality grade discrimination method for Gastrodia elata powderusing ATR-FTIR and chemometrics

Gastrodia elata is an obligate fungal symbiont used in traditional Chinese medicine. There are currently 4 grades of the plant based on the "Commodity Specification Standard of 76 Kinds of Medicinal Materials". The traditional discrimination methods for determining the medicinal grade of G. elata powders are complex and time-consuming which are not suitable for rapid analysis. We developed a rapid analysis method for this plant using attenuated total reflection and Fourier-transform infrared spectroscopy (ATR-FTIR) together with machine learning algorithms. The original spectroscopic data was first pre-treated using the multiplicative scatter correction (MSC) method and 4 principal components were extracted using extremely randomized trees (Extra-trees) and principal component analysis (PCA) algorithms, and different kinds of classification models were established. We found that multilayer perceptron classifier (MLPC) modeling was superior to support vector machine (SVM) and resulted in validation and prediction accuracies of 99.17% and 100%, respectively and a modeling time of 2.48 s. The methods established from the current study can rapidly and effectively distinguish the 4 different types of G. elata powders and thus provides a platform for rapid quality inspection.

Linking the Dynamic Changes in the In Vitro Antioxidant Activity of Carob Kibbles upon Roasting to the Chemical and Structural Changes Revealed by FTIR Spectroscopy

Recent studies have highlighted the potential of utilizing carob kibbles as a bioactive-rich food ingredient associated with substantial health benefits. Roasting is a key process in enhancing the sensory characteristics of carob kibbles, also affecting the bioactive polyphenols and leading to the formation of Maillard reaction products (MRPs), including the polymeric melanoidins that are associated with a high antioxidant potential but remain unexplored in carob. In this work, we employed for the first time attenuated total reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy to probe the dynamic chemical and structural changes upon the roasting of carob kibbles, along with the investigation of the in vitro antioxidant activity through the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and the determination of the total polyphenolic, proanthocyanidin, gallic acid and cinnamic acid contents. Roasting significantly enhanced the in vitro antioxidant activity of the polyphenolic carob extracts, with different rates at distinct roasting temperatures. The ATR-FTIR analysis enabled the identification of the changes in the structural features of polyphenolic compounds that were related to the improved antioxidant activity upon roasting. Furthermore, the detection of characteristic signatures for the polymeric melanoidins in the infrared (IR) fingerprint region provided the first evidence for the formation and structural properties of these complex, diverse compounds in roasted carob kibbles.

Discrimination of white automotive paint samples using ATR-FTIR and PLS-DA for forensic purposes

The consequences of a hit-and-run car crash are significant and may include serious injuries to the victims, health system overload and even victim's death. The vehicle and driver identification are often challenging for local law enforcement. The aim of this study was to develop a methodology to discriminate between automotive paint samples according to the make of the vehicle and its color shade. 143 white samples (collected at traffic accident scenes) were analyzed in situ by Fourier transform infrared spectroscopy with attenuated total reflectance (ATR-FTIR) and coupled microscopy. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were performed for data analysis. The samples were split into three groups: calibration set, validation set and external test set. The figures of merit were calculated to assess the quality of the model. Sensitivity, specificity, and efficiency rates were, respectively, 98,9%, 98.4% and 98.6%, for the calibration set. For the validation group, the classification accuracy was 100%. Correct classification rates for the internal validation set and external test set were 100% and 79.1% respectively. The technique is clean, fast, relatively low-cost, and non-destructive. Damaged regions of the samples were avoided by using the attached microscope. Limiting the age of the samples to a maximum of 10 years was enough to avoid misclassifications due to the natural degradation and weathering of the sample. Since the external test group is formed by underrepresented classes, its correct classification rate (79.1%) can be potentially improved at any time, by including and analyzing more samples.

Diagnosis of Lung Cancer by ATR-FTIR Spectroscopy and Chemometrics

Lung cancer is the leading cause of cancer-related death in the world. Early diagnosis has great significance for the survival of patients with lung cancer. In this paper, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy combined with chemometrics was used to study the serum samples from patients with lung cancer and healthy people. The results of spectral band area comparison showed that the concentrations of protein, lipid and nucleic acids molecules in serum of patients with lung cancer were increased compared with those in healthy people. The original spectra were preprocessed to improve the accuracy of principal component regression (PCR) and partial least squares-discriminant analysis (PLS-DA) models. PLS-DA results for first derivative spectral data in nucleic acids (1250-1000cm-1) band showed 80% sensitivity, 91.89% specificity and 87.10% accuracy with highR c 2 of 0.8949 andR v 2 of 0.8153, low RMSEC of 0.3136 and RMSEV of 0.4180. It is shown that ATR-FTIR spectroscopy combined with chemometrics might be developed as a simple method for clinical screening and diagnosis of lung cancer.

Iodine excess induces hepatic, renal and pancreatic injury in female mice as determined by attenuated total reflection Fourier-transform infrared spectrometry

Limited knowledge of the long-term effects of excessive iodine (EI) intake on biomolecular signatures in the liver/pancreas/kidney prompted this study. Herein, following 6 months of exposure in mice to 300, 600, 1200 or 2400 μg/L iodine, the biochemical signature of alterations to the liver/pancreas/kidney was profiled using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy coupled with principal component analysis-linear discriminant analysis (PCA-LDA). Our research showed that serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), serum creatinine (Scr), insulin, blood glucose levels and homeostasis model assessment for insulin resistance (HOMA-IR) index in the 1200 and 2400 μg/L iodine-treated groups were significantly increased compared with those in the control group. Moreover, histological analysis showed that the liver/kidney/pancreas tissues of mice exposed to EI treatment displayed substantial morphological abnormalities, such as a loss of hepatic architecture, glomerular cell vacuolation and pancreatic neutrophilic infiltration. Notably, EI treatment caused distinct biochemical signature segregation between EI-exposed versus the control liver/pancreas/kidney. The main biochemical alterations between EI-exposed and control groups were observed for protein phosphorylation, protein secondary structures and lipids. The ratios of amide I-to-amide II (1674 cm^-1 /1570 cm^-1 ), α-helix-to-β-sheet (1657 cm^-1 /1635 cm^-1 ), glycogen-to-phosphate (1030 cm^-1 /1086 cm^-1 ) and the peptide aggregation (1 630 cm^-1 /1650 cm^-1 ) level of EI-treated groups significantly differed from the control group. Our study demonstrated that EI induced hepatic, renal and pancreatic injury by disturbing the structure, metabolism and function of the cell membrane. This finding provides the new method and implication for human health assessment regarding long-term EI intake.

Environmental Aspects of Oxide Nanoparticles: Probing Oxide Nanoparticle Surface Processes Under Different Environmental Conditions

Surface chemistry affects the physiochemical properties of nanoparticles in a variety of ways. Therefore, there is great interest in understanding how nanoparticle surfaces evolve under different environmental conditions of pH and temperature. Here, we discuss the use of vibrational spectroscopy as a tool that allows for in situ observations of oxide nanoparticle surfaces and their evolution due to different surface processes. We highlight oxide nanoparticle surface chemistry, either engineered anthropogenic or naturally occurring geochemical nanoparticles, in complex media, with a focus on the impact of (a) pH on adsorption, intermolecular interactions, and conformational changes; (b) surface coatings and coadsorbates on protein adsorption kinetics and protein conformation; (c) surface adsorption on the temperature dependence of protein structure phase changes; and (d) the use of two-dimensional correlation spectroscopy to analyze spectroscopic results for complex systems. An outlook of the field and remaining challenges is also presented.