Attenuated Total Reflection Spectroscopy Research Articles

Recovery of Chromium and Two Solvents (Dichloromethane-DCM Tetrachloroethane-TCE) Using Nanofiltration and Reverse Osmosis Membranes from Leather Industry Wastewater

In this study, for removal of the leather industry pollutants and to recovery of chromium (Cr), dichloromethane (DCM) and tetrachloroethane (TCE) two sequential nanofiltration (NF) (NF90 and NF270) and two reverse osmosis (RO) (BW30 and SW30) reactor membranes were used. The membrane surface properties were investigated by Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) and Scanning Electron Microscopy (SEM). The permeate of the SW30 reverse osmosis exhibited high removals varying between 98% and 99% for sodium ion (Na+ ), potassium ion (K+ ), magnesium ions (Mg2+), calcium ions (Ca2+), total chemical oxygen demand (CODtotal), dissolved chemical oxygen demand (CODdis), dissolved organic carbon (DOC) and inert chemical oxygen demand (inert COD), Chromium (Cr3+ ), Dichloromethane and Tetrachloroethane. In the NF90 nanofiltration process lower removals were detected (96%-97%) for all pollutants mentioned above. The effluent of reverse osmosis with a BW30 membrane match to the Turkish Water Pollution Control Regulation rules for treated water discharged to the receiving environment while SW30 reverse osmosis membrane was perfect for ultimate treatment of the pollutants present in the leather industry discharges. From the concentrate of the SW30 reverse osmosis, 945 mg/l chromium, 460 mg/l dichloromethane and 360 mg/l tetrachloroethane were reused. The performance and recoveries of Cr and two solvents (DCM and TCE) data in NF and RO membrane reactors were evaluated with Artificial Neural Network (ANN) process and Kruskal Wallis test statistic coupled with Mann-Whitney U statistic in this study.

Development of a Measurement System Using Infrared Spectroscopy-Attenuated Total Reflectance, Principal Component Analysis and Artificial Intelligence for the Safe Quantification of the Nucleating Agent Sorbitol in Food Packaging.

Sorbitol derivatives and other additives are commonly used in various products, such as packaging or food packaging, to improve their mechanical, physical, and optical properties. To accurately and precisely evaluate the efficacy of adding sorbitol-type nucleating agents to these articles, their quantitative determination is essential. This study systematically investigated the quantification of sorbitol-type nucleating agents in food packaging made from impact copolymers of polypropylene (PP) and polyethylene (PE) using attenuated total reflectance infrared spectroscopy (ATR-FTIR) together with analysis of principal components (PCA) and machine learning algorithms. The absorption spectra revealed characteristic bands corresponding to the C-O-C bond and hydroxyl groups attached to the cyclohexane ring of the molecular structure of sorbitol, providing crucial information for identifying and quantifying sorbitol derivatives. PCA analysis showed that with the selected FTIR spectrum range and only the first two components, 99.5% of the variance could be explained. The resulting score plot showed a clear pattern distinguishing different concentrations of the nucleating agent, affirming the predictability of concentrations based on an impact copolymer. The study then employed machine learning algorithms (NN, SVR) to establish prediction models, evaluating their quality using metrics such as RMSE, R2, and RMSECV. Hyperparameter optimization was performed, and SVR showed superior performance, achieving near-perfect predictions (R2 = 0.9999) with an RMSE of 0.100 for both calibration and prediction. The chosen SVR model features two hidden layers with 15 neurons each and uses the Adam algorithm, balanced precision, and computational efficiency. The innovative ATR-FTIR coupled SVR model presented a novel and rapid approach to accurately quantify sorbitol-type nucleating agents in polymer production processes for polymer research and in the analysis of nucleating agent derivatives. The analytical performance of this method surpassed traditional methods (PCR, NN).

Application of a Bio-waste Einkorn (Triticum monococcum L.) Husks Adsorbent for Removal of Metanil Yellow and Methylene Blue from Aqueous Media with Equilibrium, Kinetic, and Thermodynamic Studies

In this study, the activated carbon (TmAC) with a high surface area and appropriate pore distribution was produced from einkorn (Triticum monococcum L.) husks by using ZnCl2 with chemical activation method. The efficiency of the obtained activated carbon on the adsorption of anionic (metanil yellow) and cationic (methylene blue) dyestuffs from aqueous solutions was investigated in more detail. In addition, the surface characterization of activated carbon was performed using thermogravimetric analysis-differential thermal analysis (TGA-DTA), elemental analysis, scanning electron microscopy (SEM) images, Brunauer–Emmett–Teller (BET) specific surface areas, N2 adsorption–desorption isotherms, pore volumes, pore size distributions, and Fourier-transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) spectra. The highest surface area of activated carbon was measured as 1321 m2 g−1 at the carbonization temperature of 500 °C by using impregnation ratio (w/w = 2.0). Batch method was used in adsorption experiments. The parameters affecting the adsorption studies such as adsorbent concentration, initial dye concentration, adsorption time, temperature, and pH were investigated. The adsorption mechanisms of metanil yellow (MY) and methylene blue (MB) on activated carbon were explained by using isotherms (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich), kinetic models (pseudo-first-order and pseudo-second-order), and the thermodynamic parameters (Gibbs free energy, enthalpy, and entropy).Graphical

Development and validation of a quick, automated, and reproducible ATR FT-IR spectroscopy machine-learning model for Klebsiella pneumoniae typing.

The reliability of Fourier-transform infrared (FT-IR) spectroscopy for Klebsiella pneumoniae typing and outbreak control has been previously assessed, but issues remain in standardization and reproducibility. We developed and validated a reproducible FT-IR with attenuated total reflectance (ATR) workflow for the identification of K. pneumoniae lineages. We used 293 isolates representing multidrug-resistant K. pneumoniae lineages causing outbreaks worldwide (2002-2021) to train a random forest classification (RF) model based on capsular (KL)-type discrimination. This model was validated with 280 contemporaneous isolates (2021-2022), using wzi sequencing and whole-genome sequencing as references. Repeatability and reproducibility were tested in different culture media and instruments throughout time. Our RF model allowed the classification of 33 capsular (KL)-types and up to 36 clinically relevant K. pneumoniae lineages based on the discrimination of specific KL- and O-type combinations. We obtained high rates of accuracy (89%), sensitivity (88%), and specificity (92%), including from cultures obtained directly from the clinical sample, allowing to obtain typing information the same day bacteria are identified. The workflow was reproducible in different instruments throughout time (>98% correct predictions). Direct colony application, spectral acquisition, and automated KL prediction through Clover MS Data analysis software allow a short time-to-result (5 min/isolate). We demonstrated that FT-IR ATR spectroscopy provides meaningful, reproducible, and accurate information at a very early stage (as soon as bacterial identification) to support infection control and public health surveillance. The high robustness together with automated and flexible workflows for data analysis provide opportunities to consolidate real-time applications at a global level. IMPORTANCE We created and validated an automated and simple workflow for the identification of clinically relevant Klebsiella pneumoniae lineages by FT-IR spectroscopy and machine-learning, a method that can be extremely useful to provide quick and reliable typing information to support real-time decisions of outbreak management and infection control. This method and workflow is of interest to support clinical microbiology diagnostics and to aid public health surveillance.

Effect of steam explosion pretreatment on chosen saccharides yield and cellulose structure from fast-growing poplar (Populus deltoides × maximowiczii) wood

The aim of this study was to determine the changes occurring in the wood cellulose of the fast-growing poplar (Populus deltoides × maximowiczii) under the influence of steam explosion (SE) pretreatment. Cellulose from native wood and after pretreatment at 160 and 205 °C was isolated. Cellulose polymerization degree by size exclusion chromatography (SEC) and cellulose crystallinity index by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) were determined. The profiles of sugars in the native wood and in the solid fraction after pretreatment (using the acid hydrolysis method) were also determined. In addition, the profile of monosaccharides in the liquid fraction obtained after steam explosion and in the liquid fraction after acid hydrolysis of the oligosaccharides were investigated using high-performance liquid chromatography (HPLC). This allowed to determine the change in the yield of hexoses and pentoses in the studied material.The behavior of cellulose in wood subjected to steam explosion at 160 and 205 °C and isolated by the Kürschner–Hoffer method was studied by determining the absorption bands of FTIR-ATR spectra. The lateral order index (LOI) of cellulose was calculated from the ratio of the intensity of the corresponding absorption bands A1422/A896 cm−1. Total crystallinity index (TCI) of cellulose was calculated from the ratio of the intensity of absorption bands A1372/A2900 cm−1. TCI of Kürschner-Hoffer cellulose isolated from wood subjected to steam explosion at 160 and 205 °C decreased by 5.6 and 5.0%, respectively, with regard to the applied temperature. LOI increased in cellulose isolated from wood subjected to steam explosion at 160 °C (by 0.7%) and at 205 °C (by 19.2%) in relation to the index of cellulose isolated from native wood. Kürschner–Hoffer cellulose isolated from wood subjected to steam explosion at 160 and 205 °C exhibited, respectively, a reduced degree of polymerization of about 11% and about 8%. Polydispersity index in Kürschner–Hoffer cellulose was 1% lower after both pretreatments than native sample.

ATR-FTIR spectroscopy and LDA: a rapid, non-destructive and cost effective strategy to trace the geographical origin of Cannabis sativa L

Abstract Cannabis recreational and/or medicinal use have been legalized in the past years in many states and countries. As a consequence, many Cannabis growers and product developers have emerged in a new market throughout the world; at the same time, issues regarding questionable quality control have also risen, as several reports on Cannabis users’ health-related problems caused by inaccurate labeling content in Cannabis-based medicines, edibles or other derivatives are being published and brought out to the public’s attention. These facts make traceability methodologies crucial whether for forensic use, such as drug trafficking eradication, or for quality control purposes of legal Cannabis and of products derived from it. Hence, the objective of this study was to analyze Cannabis by means of Attenuated Total Reflection Spectroscopy (ATR-FTIR) in order to assess the capability of this technique to trace the geographical origin of Cannabis cultivated in Brazil and in Colorado, United States of America. Forty-seven samples from Brazil and 18 samples from Colorado were analyzed by ATR-FTIR. Linear Discriminant Analysis (LDA) was employed to source the samples. The combination of ATR-FTIR and LDA achieved up to 95.23% accuracy in assigning Cannabis samples to their geographical locations of origin in Brazil and up to 100% in Colorado.

The Crystallization Behavior of a Na2O-GeO2-P2O5 Glass System: A (Micro)Structural, Electrical, and Dielectric Study.

Sodium-phosphate-based glass-ceramics (GCs) are promising materials for a wide range of applications, including solid-state sodium-ion batteries, microelectronic packaging substrates, and humidity sensors. This study investigated the impact of 24 h heat-treatments (HT) at varying temperatures on Na-Ge-P glass, with a focus on (micro)structural, electrical, and dielectric properties of prepared GCs. Various techniques such as powder X-ray diffraction (PXRD), infrared spectroscopy-attenuated total reflection (IR-ATR), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) were employed. With the elevation of HT temperature, crystallinity progressively rose; at 450 °C, the microstructure retained amorphous traits featuring nanometric grains, whereas at 550 °C, HT resulted in fully crystallized structures characterized by square-shaped micron-scale grains of NaPO3. The insight into the evaluation of electrical and dielectric properties was provided by Solid-State Impedance Spectroscopy (SS-IS), revealing a strong correlation with the conditions of controlled crystallization and observed (micro)structure. Compared to the initial glass, which showed DC conductivity (σDC) on the order of magnitude 10-7 Ω-1 cm-1 at 393 K, the obtained GCs exhibited a lower σDC ranging from 10-8 to 10-10 Ω-1 cm-1. With the rise in HT temperature, σDC further decreased due to the crystallization of the NaPO3 phase, depleting the glass matrix of mobile Na+ ions. The prepared GCs showed improved dielectric parameters in comparison to the initial glass, with a noticeable increase in dielectric constant values (~20) followed by a decline in dielectric loss (~10-3) values as the HT temperatures rise. Particularly, the GC obtained at @450 stood out as the optimal sample, showcasing an elevated dielectric constant and low dielectric loss value, along with moderate ionic conductivity. This research uncovers the intricate relationship between heat-treatment conditions and material properties, emphasizing that controlled crystallization allows for precise modifications to microstructure and phase composition within the remaining glassy phase, ultimately facilitating the fine-tuning of material properties.

Exploration of antioxidant activities, microstructural properties, and fatty acid composition of three cyanobacteria species

Cyanobacteria have gained increasing attention in the food and pharmaceutical industries as a natural source of antioxidants. However, more knowledge is needed regarding the antioxidant and nutritional properties of cyanobacteria found in water bodies worldwide, including those in Sri Lanka. This study investigated the antioxidant activities and microstructural properties using FTIR-ATR (Fourier Transform Infrared Spectroscopy-Attenuated total reflectance) analysis and the fatty acid composition of three cyanobacterial species: Chroococcidiopsis sp., Gleocapsa sp., and Merismopedia sp., which were isolated from water bodies in Sri Lanka. The water extract of Chroococcidiopsis sp. Exhibited the highest (p ≤ 0.05) phenolic content (2.26 ± 0.09 mg GAE/g DW) and ABTS activity (13.28 ± 0.36 mmol TE/g DW) among the tested species. The methanol extract of Merismopedia sp. Displayed the highest (p ≤ 0.05) DPPH activity (IC50-15.21 mg/mL) and notable (p ≤ 0.05) ORAC values (112.50 ± 5.79 mmol TE/g DW). Analysis by FTIR-ATR revealed the presence of nutritional components, including proteins, lipids, and polysaccharides, as well as functional compounds such as phenolics and amides in the studied cyanobacterial species. The fatty acid composition indicated that the studied cyanobacteria contain twenty different saturated and unsaturated fatty acids, with compositions ranging from 60 to 70% and 29–39%, respectively. Saturated fatty acids, caprylic, capric, pentadecanoic, heptadecanoic, palmitic, and lignoceric acids, were detected in all species, while elaidic, palmitoleic, and Cis-10- heptadecanoic acids were identified as prominent monounsaturated fatty acids among them. Gleocapsa sp. Had the highest (p ≤ 0.05) saturated fatty acid content, while Merismopedia sp. Showed the highest (p ≤ 0.05) unsaturated fatty acid content. Based on the results, Merismopedia sp. Has demonstrated promising potential as a rich source of antioxidants and unsaturated fatty acids.

A disposable optofluidic micro-transmission cell with tailorable length for Fourier-transform infrared spectroscopy of biological fluids.

Mid-infrared Fourier-transform infrared (FT-IR) spectroscopy of liquid biological samples is limited by the high absorption of water in this spectral range, which makes conventional transmission cuvettes unsuitable as their centimeter-scale length is already too big. The most common alternative relies on the use of attenuated total reflection (ATR) accessories, which provide a small interaction path length for light along the interface between the analyte and the expensive ATR crystals. In this work, we address this issue by proposing a disposable and low-cost micro-transmission cell. Its construction relies on a simple technique, which consists of dispersing plastic spherical microparticles in a liquid sample before dispensing it between two pieces of silicon assembled one onto the other and acting as windows for the cell. Consequently, the microparticles act as a spacer of very precise height in-between the two silicon windows. This technique allows easy construction of infrared absorption cells with near-optimum optical interaction path length just by selecting the most appropriate particle size. The concept is demonstrated by measuring the concentration of glucose in aqueous solutions using microspheres of diameter 20 μm then 40 μm and analyzing the corresponding glucose absorption peaks in the wavenumber range 950-1200 cm-1. The performance is compared to that of standard ATR spectroscopy of the same samples. This resulted in a root-mean-square error of cross-validation (RMSECV) of 58.8 mg dl-1 as obtained for transmission measurements by partial least squares (PLS) regression, which is comparable to the RMSECV of 53 mg dl-1 for single-reflection diamond ATR measurements.

Surface roughness of pigmented and non-pigmented maxillofacial silicone elastomer before and after artificial aging

Maxillofacial prostheses are frequently made from silicone elastomer. The silicone material’s rough surface can lead to the accumulation of microorganisms, irritation of the surrounding soft tissue, and the progression of some microsites into mechanical failure and color deterioration. This in vitro study aimed to compare the surface roughness of M511 heat-vulcanized maxillofacial silicone before and after artificial aging. Eighty disk-shaped specimens were prepared and divided equally among five experimental groups based on pigmentation, with 16 samples in each group. The colorless specimens were prepared without adding any pigment. The four study groups were prepared using distinct pigments (red, blue, yellow, and their mixture). Half of the specimens in each group were tested before aging, while the other half was tested after 750 h of artificial aging. Surface roughness was measured using atomic force microscopy (AFM), and the silicone bonds and pigments were observed using Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). Data were compared between groups using a two-way analysis of variance, independent sample t-test, and Tukey’s post hoc test, considering a p < 0.05 statistically significant. FTIR-ATR showed no differences between the pre-and post-aging groups, with similar peaks observed. The surface roughness significantly increased in the colorless, blue, and mixed pigment groups (p < 0.001), surface roughness increased by 155.66%, 14.83%, and 96.12% respectively for colorless, blue pigment, and the mixture of pigments after 750 h of artificial aging. In contrast, the surface roughness significantly decreased in the yellow pigment (90.98%) and red pigment (5.7%) (p ≤ 0.001) after aging. The yellow pigment showed the smoothest surface after aging, while colorless specimens showed the roughest surface. Two-way ANOVA showed that pigment type and aging time significantly affected surface roughness. Therefore, induced aging considerably impacted the surface topography of maxillofacial silicone. The pigment type and distribution in the silicone matrix affected its surface roughness. The AFM analysis is a simple and straightforward method for assessing surface roughness at the nanometer level.

Preparation of Co–CaCO3 catalysts for improved hydrogen production from sodium borohydride

Ca1-xCoxCO3 nanoparticle catalysts (x = 0.0, 0.1, 0.2 and 0.3 %) were prepared by the sol-gel method. The samples were characterized using various techniques such as X-ray diffraction (XRD), attenuated total reflectance spectroscopy (ATR), environmental scanning electron microscopy (ESEM), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) surface area analysis. The XRD peaks of Ca1-xCoxCO3 displayed a significant level of conformity with the rhombohedral calcite structure. The average crystal size of Ca1-xCoxCO3 nanoparticles was found to be 14 nm. The ESEM micrographs of Ca1-xCoxCO3 showed rhombic calcite shapes. The most prominent peaks in the XPS spectra of Ca1-xCoxCO3 are the Ca 2p, C 1s, Co 2p and O 1s peaks. The sample Ca1-xCoxCO3 has the highest surface area (58.27 m2/g) and large pore size (20.25 Å). The rates of hydrogen production for CaCO3, Ca0.9Co0.1CO3, Ca0.8Co0.2CO3 and Ca0.7Co0.3CO3 were 5204, 4381, 6666 and 6136 mL/g.min. The Ca0.8Co0.2CO3 catalyst revealed an activation energy for hydrogen catalytic reaction of 34.56 kJ/mol. The recyclability tests of Ca1-xCoxCO3 catalysts showed a reduction of efficiency by 7 % over 5 reaction cycles. Accordingly, the prepared Ca1-xCoxCO3 catalysts are promising for improved hydrogen production systems. This research contributes to advancements in hydrogen production technology.

Seasonal variation of microplastics in tropical mangrove waters of South-western India

The current study investigates the seasonal variations in microplastic (MP) contamination, specifically those ranging in size from 0.1 mm to 5 mm, within the tropical mangroves of Kota, South-western India. Mean concentrations ( ± standard deviation) of 1.42 ± 0.92 MPs/L (post-monsoon), 0.62 ± 0.38 MPs/L (pre-monsoon), and 0.19 ± 0.08 MPs/L (monsoon) were observed. Fibers emerged as the most abundant category across all samples, with a dominant size fraction of less than 1 mm. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) analyses identified various polymer types, including polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polystyrene (PS), and polyvinyl chloride (PVC). Potential sources of microplastic contamination in the region could be ascribed to tourism, marine product-related industries, prawn farming, and residents. The findings of this study offer crucial insights into the seasonal fluctuations of microplastic contamination in the Kota mangrove ecosystem.

Mineralization characteristics and behavior of polyethylene microplastics through ozone-based treatment

The elimination of microplastics (MPs) has become an urgent issue due to their large quantities and imperfect treatment technologies. In this work, polyethylene (PE), which is ubiquitous in the environment, was selected to study its removal by ozone-based treatment. Catalysts including α-MnO2 and α-FeOOH were synthesized for catalytic ozonation to improve efficiency. The study focused on simulating the conversion of CO2 in the off-gas via the detection of inorganic carbon produced. The morphology and structure of the remaining PE MPs were characterized using scanning electron microscope and Fourier-transform infrared spectroscopy-attenuated total reflection. Our results confirmed that fragmentation and oxidation occurred in the remaining PE MPs, which enhanced the adsorption capacity of ofloxacin (OF). Besides, the 20 mM α-FeOOH could better improve the mineralization efficiency by 3.27 folds with more production of •OH (1.09*10−12 M). Moreover, possible products identified by liquid chromatography-time-of-flight mass spectrometer confirmed the decomposition of main chains of MPs into low-molecular-weight organic compounds with functional groups such as C–OH, C–O–C, and CO. The finding that photoaged PE MPs could be efficiently mineralized under the attack of O3/•OH provides a solid foundation for the removal of natural MPs in the environment.

Effects of Gamma Irradiation on the Properties of Hydroxyapatite-Collagen-Chitosan-Mg-ZnO Scaffolds for Bone Tissue Engineering

Bone tissue engineering aims to repair diseased or damaged bone that cannot be regenerated naturally. This study is designed to develop biodegradable porous scaffolds as bone substitutes and evaluate the effect of gamma irradiation on these scaffolds for the restoration of defected bone. Here, composite scaffolds (HA-COL-CS-Mg-ZnO) were prepared by the thermally induced phase separation (TIPS) technique using collagen (COL) and chitosan (CS), hydroxyapatite (HA), magnesium (Mg), and zinc oxide (ZnO) at different mass ratios. Thereafter, the scaffolds were subjected to 10 KGy γ-radiation for physical cross-linking and sterilization. The physicochemical and biological properties of the scaffolds were evaluated by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), field emission scanning electron microscopy (FESEM), physical stability (biodegradability, swelling rate, porosity, and density), mechanical properties, biocompatibility, cytotoxicity, and antimicrobial activity against Escherichia coli (ATCC-25922) and Staphylococcus aureus (ATCC-25923). We found that the irradiated scaffold showed enhanced tensile strength and antimicrobial activities which are desirable characteristics of bone-mimicking scaffolds. FESEM revealed that the average pore size decreased from 192.3 to 104.5 μm due to radiation. FTIR-ATR spectra showed that γ-radiation triggered cross-linking in the polymer matrix which improved mechanical strength (0.82 N/mm2 to 1.86 N/mm2) by increasing pore wall thickness. Moreover, the irradiated and nonirradiated scaffolds were biocompatible and noncytotoxic toward the Vero cell line which ensured their suitability for use in vivo. These results demonstrate that sterilization of HA-COL-CS-Mg-ZnO scaffolds with gamma-irradiation substantially improves the physicochemical and morphological features which aid bone tissue regeneration and could be supportive for new bone formation.

Application of Optical Photothermal Infrared (O-PTIR) Spectroscopy for Assessment of Bone Composition at the Submicron Scale.

The molecular basis of bone structure and strength is mineralized collagen fibrils at the submicron scale (∼500 nm). Recent advances in optical photothermal infrared (O-PTIR) spectroscopy allow the investigation of bone composition with unprecedented submicron spatial resolution, which may provide new insights into factors contributing to underlying bone function. Here, we investigated (i) whether O-PTIR-derived spectral parameters correlated to standard attenuated total reflection (ATR) Fourier transform infrared spectroscopy spectral data and (ii) whether O-PTIR-derived spectral parameters, including heterogeneity of tissue, contribute to the prediction of proximal femoral bone stiffness. Analysis of serially demineralized bone powders showed a significant correlation (r = 0.96) between mineral content quantified using ATR and O-PTIR spectroscopy, indicating the validity of this technique in assessing bone mineralization. Using femoral neck sections, the principal component analysis showed that differences between O-PTIR and ATR spectra were primarily attributable to the phosphate ion (PO4) absorbance band, which was typically shifter toward higher wavenumbers in O-PTIR spectra. Additionally, significant correlations were found between hydrogen phosphate (HPO4) content (r = 0.75) and carbonate (CO3) content (r = 0.66) quantified using ATR and O-PTIR spectroscopy, strengthening the validity of this method to assess bone mineral composition. O-PTIR imaging of individual trabeculae at 500 nm pixel resolution illustrated differences in submicron composition in the femoral neck from bones with different stiffness. O-PTIR analysis showed a significant negative correlation (r = -0.71) between bone stiffness and mineral maturity, reflective of newly formed bone being an important contributor to bone function. Finally, partial least squares regression analysis showed that combining multiple O-PTIR parameters (HPO4 content and heterogeneity, collagen integrity, and CO3 content) could significantly predict proximal femoral stiffness (R2 = 0.74, error = 9.7%) more accurately than using ATR parameters. Additionally, we describe new findings in the effects of bone tissue orientation in the O-PTIR spectra. Overall, this study highlights a new application of O-PTIR spectroscopy that may provide new insights into molecular-level factors underlying bone mechanical competence.

Dye removal membrane from electrospun nanofibers of blended polybutylenesuccinate and sulphonated expanded polystyrene waste

Polystyrene (PS) is a thermoplastic polymer used in food packaging and the manufacture of trays and cups, among other applications. In this work, the preparation of a membrane by electrospinning blended sulphonated expanded PS waste and polybutylenesuccinate (PBS) is described. The fiber quality is controlled by selecting the right polymers’ ratios and solvents. Investigation of the structure of the produced membranes by Fourier transform infrared spectroscopy-attenuated total reflectance confirmed the successful sulphonation of expanded PS and the appearance of characteristic (PBS) bands in the prepared blends. Morphology study of the electrospun membranes using a scanning electron microscope revealed that the quality of the fibers is improved significantly by increasing the amount of PBS in the blend solution. Moreover, continuous and more homogenous fibers are produced by increasing the ratio of PBS to 2%. The efficiency of the prepared membranes in dye removal was tested using methylene blue. The effects of different parameters such as, pH, contact time, temperature, and dye concentration have been studied. Also, kinetic and adsorption isotherm models as well as the durability of the prepared membranes were investigated. The membrane prepared from PSS/1% PBS demonstrated the highest dye uptake (846 mol) with good regeneration efficiency. The adsorption process was found to be endothermic and fits the Freundlich isotherm and pseudo-second-order kinetic model. The values of activation energy for the adsorption process are 36.98, 30.70, and 43.40 kJ/mol over PSS, PSS/1% PBS and PSS/2% PBS, respectively.

Laboratory Studies about Microplastic Aging and Its Effects on the Adsorption of Chlorpyrifos.

The constant change in microplastics (MP) due to exposure to environmental conditions leads to physical and chemical changes that enhance their ability to transport other pollutants, increasing the concern about their widespread presence in the environment. This work aimed to simulate the aging process of six MP (polyamide 6, unplasticized polyvinyl chloride, low-density polyethylene, polystyrene, polyethylene-co-vinyl acetate, polypropylene) in freshwater and seawater ecosystems at laboratory scale and evaluate its effects through optical microscope observation, Fourier transform infrared spectroscopy-Attenuated Total Reflectance (FTIR-ATR), Raman spectroscopy, and thermal gravimetric analysis (TGA). Through a combined experimental study of aged MP, the degradation by UV interaction was evidenced by the appearance of new infrared bands in the FTIR spectra assigned to ketones and hydroxyl groups. While Raman analysis and microscope images reveal the appearance of pores, wrinkles, and roughness in the MP surfaces. Variations in the temperature of the maximum weight loss of the MP were observed in the TGA analysis. The adsorption of chlorpyrifos (CPF), a common pesticide widely used in agriculture, by the pristine and aged MP was also studied. The highest affinity for CPF was observed for pristine LDPE and the lowest for PP. The batch adsorption studies revealed an increase in adsorption capacity as a consequence of the aging process for both MP. These results proved that the weathering effects caused changes in the behavior of MP, namely in the interaction with other pollutants.

Accelerated in vitro oxidative degradation testing of polypropylene surgical mesh.

Polypropylene (PP) surgical mesh had reasonable success in repair of hernia and treatment of stress urinary incontinence (SUI); however, their use for the repair of pelvic organ prolapse (POP) resulted in highly variable results with lifelong complications in some patients. One of several factors that could be associated with mesh-related POP complications is changes in the properties of the implanted surgical mesh due to oxidative degradation of PP in vivo. Currently, there are no standardized in vitro bench testing methods available for assessing the susceptibility to oxidative degradation and estimating long-term in vivo stability of surgical mesh. In this work, we adapted a previously reported automated reactive accelerated aging (aRAA) system, which uses elevated temperatures and high concentrations of hydrogen peroxide (H2 O2 ), for accelerated bench-top oxidative degradation testing of PP surgical mesh. Since H2 O2 is highly unstable at elevated temperatures and for prolonged periods, the aRAA system involves a feedback loop based on electrochemical detection methods to maintain consistent H2 O2 concentration in test solutions. Four PP mesh samples with varying mesh knit designs, filament diameter, weight, and % porosity, were selected for testing using aRAA up to 4 weeks and characterized using thermal analysis, Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and scanning electron microscopy (SEM). Additionally, the oxidation index (OI) values were calculated based on the FTIR-ATR spectra to estimate the oxidative degradation and oxidation reaction kinetics of PP surgical mesh. The OI values and surface damage in the form of surface flaking, peeling, and formation of transverse cracks increased with aRAA aging time. The aRAA test method introduced here could be used to standardize the assessment of long-term stability of surgical mesh and may also be adopted for accelerated oxidative degradation testing of other polymer-based medical devices.

North and South: Exploring isotopic analysis of bone carbonates and collagen to understand post-medieval diets in London and northern England.

We evaluate the potential of paired isotopic analysis of bone carbonate and collagen to examine the diet of post-medieval human and animal populations from England (17th-19th c.), including, for the first time, manufacturing towns in northern England. The potential for identifying C4 crop consumption is explored alongside regional and local patterning in diet by sex and socioeconomic status. Humans (n = 216) and animals (n = 168) were analyzed from sites in London and northern England for both carbon and nitrogen isotopes of bone collagen (𝛿13 Ccoll , 𝛿15 Ncoll ). Isotopic analysis of bone carbonates (𝛿13 Ccarb , 𝛿18 Ocarb ) was carried out on all humans and 27 animals, using Fourier transform infrared spectroscopy-attenuated total reflectance to assess diagenesis. Variations in diet were observed between and within different populations by geographical location and socioeconomic status. Three pigs and one cow consumed C4 resources, indicating the availability of C4 -fed animal protein. Londoners consumed more animal and marine protein and C4 resources. Middle- and upper-class populations from both London and northern populations also had greater access to these foods compared to those of lower status in the same regions. This substantial multi-isotope dataset deriving from bone carbonate and collagen combined from diverse post-medieval urban communities enabled, for the first time, the biomolecular identification of the dynamics of C4 consumption (cane sugar/maize) in England, providing insight into the dynamics of food globalization during this period. We also add substantially to the animal dataset for post-medieval England, providing further insight into animal management during a key moment of agricultural change.

Phosphorous-containing flame retardant plasticizer based on Cassia fistula seed oil and their application in poly(vinyl chloride) films

The need for safety and sustainability has prompted the development of flame-retardant bio-based plasticizers from renewable resources. In this study, an efficient phosphorous-containing flame retardant plasticizer (ECFSO-P) for poly(vinyl chloride) (PVC) was synthesized using Cassia fistula seed oil and characterized by fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and proton nuclear magnetic resonance (1H NMR) spectroscopies. In replace of the dioctyl phthalate (DOP), the ECFSO-P was employed as a flame retardant plasticizer to produce poly(vinyl chloride) (PVC) blends. The PVC blends were prepared using ECFSO-P, DOP, and ECFSO-P + DOP blends as plasticizers. The PVC blends with different concentrations of DOP and ECFSO-P were investigated with thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical properties, fire retardant performance, crystallinity, leaching, volatility, and density functional theory (DFT) studies. The TGA results showed that the thermal degradation temperature of PVC blends plasticized with ECFSO-P reached 230.6 ºC. The glass transition temperature, Tg decreased to 34ºC as determined by DSC, when DOP was completely replaced with ECFSO-P. When PVC was plasticized with ECFSO-P only, the tensile strength and elongation at break reached 6.41 and 508.83, respectively. The leaching and volatility properties of ECFSO-P plasticized PVC blends were better than DOP plasticized film. Limited oxygen index (LOI) and smoke density rating (SDR) values were increased by 6.7% and 17.4%, respectively. The WAXS profiles showed that ECFSO-P did not alter the order of crystallinity among the PVC chains. As expected, the hydrogen bonding interactions between plasticizers and the -CH-Cl units of PVC were confirmed by DFT calculations.