Total Reflectance Fourier Transform Infrared Research Articles

A novel non-aqueous tertiary amine system for low energy CO2 capture developed via molecular dynamics simulation

The current technology for capturing CO2 using alkanolamine aqueous solutions is known for its high energy and capital costs. As a result, developing new absorbents for low-energy CO2 removal remains a challenge. An additional activator can promote CO2 absorption performance. However, it is based on experimental screening. In this study, based on molecular dynamic simulation, we have successfully developed a novel and energy-efficient CO2 absorbent by combining N, N-Dimethylethanolamine (DMEA), and ethylene glycol (EG), with different activators, including ethanolamine (MEA), ethylenediamine (EDA), and piperazine (PZ). The addition of these activators significantly enhances the CO2 absorption performance of DMEA-based absorbents. Among them, DMEA-PZ-EG exhibits the maximum CO2 absorption rate and capacity, achieving 6.35 (g-CO2/(kg-soln.·min.)) and 96.5 (g-CO2/kg-soln.), respectively, representing a 230.1 % and 206.35 % improvement over 2M DMEA-EG absorbent. Moreover, compared to a 30 wt% MEA solution, the energy consumption of DMEA-based absorbents is reduced by 33.93–51.56 %. The reaction products were characterized using various spectroscopic techniques, including Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), and 1D and 2D Nuclear Magnetic Resonance spectroscopy (1H and 13C NMR). The NMR results confirmed that DMEA becomes protonated after CO2 absorption in the DMEA-EG mixture. The deprotonation of EG promote its reaction with CO2, resulting in the forming of EG carbonates. This assumption has been confirmed by the IR spectrum. Furthermore, the effect of activators on CO2 absorption has been analysed at the molecular level through molecular dynamics simulation and a new method is proposed to predict the CO2 absorption performance of non-aqueous solvents. Using non-aqueous DMEA absorbents presents a promising approach for improving CO2 capture efficiency, reducing energy consumption, and facilitating regeneration.

Nanoparticle Uptake and Bioaccumulation in Pisum sativum L. (Green Pea) Analyzed via Dark-Field Microscopy, Infrared Spectroscopy, and Principal Component Analysis Combined with Machine Learning

The green pea (Pisum sativum L.) is an economically, nutritionally, and culturally important legume. It is a crop that is subject to various investigations due to its popularity with the development of various protocols in different topics, except for nano-biotechnological studies. This work was carried out to evaluate the uptake, distribution, translocation, and bioaccumulation of the single-walled carbon nanotubes (CNTs) and gold nanoparticles (AuNPs) within the economically important plant Pisum sativum morphologically and anatomically with a dark-field microscopy system. Data were analyzed for morphological parameters such as stem, tendril, root length, number, shape, width-length of the stipules, and root-stem-stipule. Our results proved the stimulation for growth and anatomical parameters such as CNTs aggregates and AuNPs particles at paranchyma, cortex, spongia cells, starch formation and accumulation in lenticels, stoma cells, and stomatal pores. In this study, we compared the utilization of the entire available Attenuated Total Reflectance—Fourier Transform Infrared Spectroscopy (ATR-FTIR) spectral range (525–4000 cm−1) for conducting principal component analysis (PCA) without excluding any specific spectral wavenumbers with the spectral range chosen based on larger PCA loadings. The results demonstrate that for both chosen spectral ranges of the PCA score plots, utilizing only the first three principal components (PCs), we effectively visually separated three groups: (1) plants treated with Au NPs, (2) plants treated with CNTs, and (3) control plants without nanoparticle treatment using ATR-FTIR spectral data from combined samples of root, stem, and leaves from the Pisum sativum plant. Our investigation shows that green pea, a species of the Fabaceae family, is low-cost, fast, and non-toxic and requires an environmentally safe process in the area of nanotechnology in bio-application regarding the green synthesis of nanoparticles; it is a step for green mining, phytoremediation, delivering drugs, and biomolecules. Our findings show that green pea and the Fabaceae family have more advantages for the biological synthesis of C-Au nanoparticles and guide soil health, agricultural development, pharmaceuticals, drug delivery science, and other types of medicinal investigations with a new approach, while a lot of economic plants in the Fabaceae family will be available for the green synthesis of more NPs with single and rapid protocols and will be a popular family in nano-biotechnological studies in the next few decades.

Performance of Chitosan/Carbon Nanotube-Coated Ultrafiltration Membranes for Natural Organic Matter Removal from Drinking Water

The objective of this study is to improve the filtration efficiency of commercially available polyethersulfone (PES) ultrafiltration (UF) membranes, with a specific focus on removing natural organic matter (NOM) and preventing membrane fouling. The modification of UF membranes was accomplished by utilizing chitosan/multi-walled carbon nanotubes (CS/MWCNT-OH) and employing both dip and spin coating techniques. The membrane surface morphologies were evaluated using the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Energy-Dispersive X-ray Spectroscopy (EDX) techniques. Tests were carried out to assess the effectiveness of the membranes in a laboratory-scale system using two primary water sources from Istanbul, specifically the Melen River and Terkos Lake. Total organic carbon (TOC), UV254 absorbance, turbidity, and trihalomethane formation potential (THMFP) were all measured as part of a thorough analysis. The surface morphology investigations verified the effective deposition of MWCNT-OH nanoparticles onto the membrane surface. This was corroborated by the reduction in the water contact angle, showing an improvement in the hydrophilicity of the membrane. The modified membranes demonstrated much higher TOC removal rates compared to the original membranes. Specifically, the removal efficiencies for Melen River and Terkos Lake were 37.14% and 56.86%, respectively. Nevertheless, the alteration of the surface led to a decline in membrane flux as a result of the concurrent drop in pore size. To summarize, the results of this work highlights the considerable capability of surface modification using CS/MWCNT-OH to improve the performance and antifouling characteristics of commercial PES UF membranes.

Eco friendly functional finishes of polyester fabric using keratin from wool and feather wastes

This research showcases the use of hydrothermally extracted solutions from poultry feathers and wool as eco-friendly and versatile textile finishes. These solutions, derived from waste biomass containing the keratin biopolymer, were obtained through environmentally conscious hydrothermal degradation processes. Initially, the study focused on analysing the chemical parameters and properties of both dialysed and non-dialysed solutions extracted from feathers and wool. The investigation tracked primarily the presence of keratin within these solutions. Upon application to polyester textiles as the reference material, the presence of these solutions on the fabric surface was confirmed successfully. A thorough physicochemical analysis of the treated textiles involved various analytical techniques. These encompassed surface composition analysis via X-ray Photoelectron Spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), assessment of wettability through Contact Angle measurements, determination of surface charge using surface zeta potential, and examination of the thermal and flame-retardant properties via Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and calorimetric tests. In addition, the colour, UV radiation transmission and antioxidant activity were evaluated using standard tests.The remarkable effects of the treatment have been observed in the exceptional antioxidative action, fire resistance, UV protection and enhanced hydrophilicity of these innovative multifunctional textiles. This approach holds significant implications across research, economics and society, enriching Material Science by deepening the understanding of materials and their multifaceted properties. Moreover, it promotes resource efficiency, opens new sustainable textile market prospects, and contributes to social impact by supporting environmental sustainability, engaging communities and ensuring health and safety benefits.

Emphasizing the Potential of Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) Spectroscopy Combined with Chemometrics, for Classification of Greek Grape Marc Spirits

Grape marc spirits, such as the Greek tsipouro/tsikoudia, reflect the cultural heritage of winemaking traditions worldwide. This study explored the application of Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) spectroscopy combined with chemometrics for its potential as a fast classification methodology for spirit characterization. ATR-FTIR spectra from thirty-nine products revealed distinctive bands corresponding to various chemical constituents, such as alcohols, organic acids, water, carbohydrates, and phenols. Principal Component Analysis (PCA) was performed on all acquired ATR-FTIR data and 78.50% of the total variance in the data was explained. Also, partial least squares–discriminant analysis (PLS-DA), used for the classification of products based on their major geographic origin, gave a correct classification of 89.5% for the north and 83.3% for the south of Greece. Classification of the type of distillations used was with 74.36% accuracy. Significant markers were identified through analysis, such as those associated with the O-H bending vibrations of phenols or alcohols, contributing to the discrimination of grape marc spirits from Crete when compared with the other four main geographical origin designations. By combining ATR-FTIR spectroscopy with chemometrics, this research gave insights into the origins and compositional variations of the spirits, providing an opportunity for a quality control assessment tool.

Green and chemical syntheses of silver nanoparticles: Comparative and comprehensive study on characterization, therapeutic potential, and cytotoxicity

The emergence of metallic nanoparticles through green synthesis has garnered significant recognition, shaping global research efforts towards eco-friendly practices, often termed as the green revolution. Specifically, the green synthesis of silver nanoparticles (AgNPs) has made considerable strides in the past decade, becoming a prominent fixture in the realm of science and technology. The study explores the synthesis and characterization of silver nanoparticles (AgNPs) using Cassia fistula L. flowers extract through chemical co-precipitation (CM_AgNPs) and green methods (CFF_AgNPs). Characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), attenuated total reflectance fourier-transform infrared (FTIR), and X-ray diffraction (XRD), revealed irregular morphologies with agglomeration, polycrystalline nature, and intrinsic functional groups involved in capping AgNPs. Antioxidant assessment demonstrated superior antioxidative activity (84.48 %) in green-synthesized nanoparticles compared to chemically synthesized ones (75.87 %), and they exhibited dose-dependent anti-inflammatory effects with IC50 values CFF_AgNPs_30.19 μg/mL and CM_AgNPs _34.14 μg/mL respectively. The lower IC50 value of CFF_AgNPs_30.19 μg/mL signifies finer and better activity due to the presence of phytochemicals present in it. Whereas for CM_AgNPs the IC50 value is a 34.14 μg/mL which is solely due to AgNPs. To ensure the promising therapeutic aspects of AgNPs with a careful assessment of their safety profile, cytotoxicity of AgNPs on HEP3B cancer cells was evaluated through MTT assay, lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) level measurement. In the in vitro cytotoxicity evaluation, HEP3B demonstrated more pronounced dose-dependent adverse effects upon exposure to CFF_AgNPs compared to CM_AgNPs. This study underscores the bioactive potential of Cassia fistula L. mediated AgNPs, suggesting promising applications in biomedicine with environmental sustainability. The findings contribute to the growing interest in green synthesis methods for metallic nanoparticles and their potential benefits in various fields.

An insight into viscosity and conductivity in the formulation of co-axial electrospun Carica papaya leaf extract

Objective: This research aimed to investigate the application of the coaxial electrospun method for the production of natural extracts (papaya leaf extract) fibre films. This was achieved through utilising different polymers and with a focus on the conductivity and the viscosity of polymer solutions as critical parameters to generate successful fibres.Significance: Electrospinning is a promising trending manufacturing method for incorporating thermolabile herbal extracts using coaxial electrospun features. However, the complexity of the electrospinning process and the feasibility of the product required precise scrutiny.Methods: The electrospinning solution parameters (conductivity and viscosity) were evaluated by employing various ratios of Eudragit L100 (EL100) and Eudragit L100-55 (EL100-55) pre-spinning polymeric blend solutions. The electrospinning process and ambient parameters were optimised. Following that, the in-silico physicochemical properties of phytochemical marker, rutin, were illustrated using SwissADME web tool. Both freeze-dried Carica papaya leaf extract and its produced films were characterised using Scanning Electron Microscopy (SEM), Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), polarised light microscopy, and X-ray Powder Diffraction (XRPD).Results: The optimal values of conductivity (≈40–44 × 10−4 S/m) and viscosity (≈32–42 × 10−3 Pa·s) were determined for producing evenly distributed and small fibre diameters in SEM images. These parameters significance was highlighted in acquiring and maintaining adequate tangential stress for fibre elongation, which would consequently affect the morphology and diameter of the fibres formed.Conclusion: In conclusion, the solution, process, and ambient parameters are significant in developing natural extracts into films via electrospinning technology, and this includes the promising Carica papaya leaf extract films produced by coaxial electrospinning.

How are plastic debris affecting the diet of the whitemouth croaker in the Southeastern Brazilian Bight?

The objective of this study was to analyze the presence of plastic debris in the digestive tract contents of Micropogonias furnieri, the most important demersal fish species from the Southeastern Brazilian Bight. In the laboratory, a total of 150 individuals were measured (230≤TL≤674 mm), weighed (136≤TW≤3221 g), and their gut contents were evaluated. The ingested food items were identified, and the plastic debris observed under the stereomicroscope were isolated and subjected to the physical analysis Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) to identify the chemical composition and to determine the polymers. A total of 190 plastic particles were observed in 51.8% of the stomachs containing food. The recovered plastic debris varied from one to twelve particles per individual (mean ± s.d. of 3.33 ± 2.25). Color varied and the particle size ranged from 0.075 to 19.139 mm. There was no relationship between the number of plastic debris recovered in the stomachs of M. furnieri and the total length, total weight, stomach weight, and percent repletion. The most common polymers were polyamide (28.42%), and polystyrene (27.37%), and the total value of polymer hazard index to M. furnieri diet was 35,544.77, corresponding to an extreme danger, with very toxic with long-lasting effects. Considering the effects of plastic ingestion by marine fish and the potential risks to human health, the contamination of the whitemouth croaker with items that are harmful to its diet reveals a problem of environmental contamination, an alarming concern about plastic pollution in marine systems.

Microplastics removal efficiency and risk analysis of wastewater treatment plants in Oman

Microplastics (MPs) have recently been documented as an emerging pollutant that poses a critical threat to environment. Wastewater treatment plants (WWTPs) are commonly regarded as significant contributors to the presence of MPs. This study aimed to assess the MPs load of three wastewater treatment facilities in Oman using various treatments, including MBR, SBR, and CAS. Wastewater samples from influent, effluent, and sludge were collected and analyzed to determine the concentration, morphology, size, color, and polymer type of the MPs. A set of sieves with a mesh size range of 1 mm–45 μm was used to for filtration. Oxidation treatment was applied for all samples using Fenton's reagent, followed by density separation by sodium chloride solution. The Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR- FTIR) method was utilized to test 10% from each sampling point to confirm the polymer types of the MPs. The pollution load index (PLI) and hazard index (HI) have been employed to assess the risk associated with the chemical toxicity and concentration of detected particles. The PROMETHEE method was used to rank the risk of sampling sites based on different criteria that posed potential ecological and human health risks. The results indicate that the average concentrations of 0.99 MP/L, 1.38 MP/L, and 0.93 MP/L were detected in the final treated effluent of WWTP A, WWTP B, and WWTP C, respectively. These concentrations correspond to overall removal efficiencies of 82.5%, 77.4%, and 79.2% for WWTP A, WWTP B, and WWTP C, respectively Most MPs found in tertiary effluent were smaller particles (425 μm) and fiber-shaped. The major types of MPs were polypropylene (PP), low-density polyethylene (LDPE), polyurethane (PU), polyethylene terephthalate (PET), and Polyvinyl chloride (PVC). This study showed that treated effluent and sludge release significant MPs into the environment.

Development of Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy Coupled with Multivariate Classification Chemometric Model for Routine Screening of Paracetamol, Ibuprofen, and Aspirin Adulteration in Herbal Products

Objective: The objective of this study is to develop and validate a routine screening test for the determination of three common antipyretic-analgesic synthetic drugs (paracetamol, ibuprofen, and aspirin) adulteration in herbal products using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) coupled with chemometric method. Methods: ATR-FTIR spectra of sixteen testing sets of herbal product samples for pain and fever indications were used for multivariate chemometrics model construction. Linear Discriminant Analysis (LDA) was selected as a method for model construction with IBM SPSS for statistical analysis. Model development employed feature selection, such as the stepwise method for variable selection. The model with a high %correct classification and cross-validation was selected and was then validated with an independent testing data set with an auto-prediction test, confusion matrix, and Receiver Operating Characteristic (ROC) curve. To validate the developed test for routine use, the result from ATR-FTIR method was compared with the standard HPLC and TLC analyses used for adulteration screening. Results: The selected model's overall %correct classification result was 97.7%, with a cross-validation of 93.8% rate in training set samples. External validation with an independent testing dataset gave an overall correct classification of 93.8%, with an area under the curve of ROC at 0.979. Comparative testing revealed that model performance was comparable with the HPLC and TLC methods, which routinely detect the presence of paracetamol, aspirin, and ibuprofen. The results of testing set samples classification were consistent with training set samples. Conclusion: Against the standard chromatographic methods, the multivariate chemometric model based on ATR-FTIR demonstrates comparable detection capability to determine adulteration of paracetamol, ibuprofen, and aspirin in herbal products.

Exploring untapped bacterial communities and potential polypropylene-degrading enzymes from mangrove sediment through metagenomics analysis.

The versatility of plastic has resulted in huge amounts being consumed annually. Mismanagement of post-consumption plastic material has led to plastic waste pollution. Biodegradation of plastic by microorganisms has emerged as a potential solution to this problem. Therefore, this study aimed to investigate the microbial communities involved in the biodegradation of polypropylene (PP). Mangrove soil was enriched with virgin PP sheets or chemically pretreated PP comparing between 2 and 4 months enrichment to promote the growth of bacteria involved in PP biodegradation. The diversity of the resulting microbial communities was accessed through 16S metagenomic sequencing. The results indicated that Xanthomonadaceae, unclassified Gaiellales, and Nocardioidaceae were promoted during the enrichment. Additionally, shotgun metagenomics was used to investigate enzymes involved in plastic biodegradation. The results revealed the presence of various putative plastic-degrading enzymes in the mangrove soil, including alcohol dehydrogenase, aldehyde dehydrogenase, and alkane hydroxylase. The degradation of PP plastic was determined using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), and Water Contact Angle measurements. The FTIR spectra showed a reduced peak intensity of enriched and pretreated PP compared to the control. SEM images revealed the presence of bacterial biofilms as well as cracks on the PP surface. Corresponding to the FTIR and SEM analysis, the water contact angle measurement indicated a decrease in the hydrophobicity of PP and pretreated PP surface during the enrichment.

Wood consolidation through an epoxy‐acrylic gamma‐crosslinked three‐dimensional system

AbstractEmerging technologies based on polymeric materials are progressively developed in order to preserve and consolidate cultural heritage artifacts. In this study, we aimed to obtain a hybrid polymer reliant on two types of thermosets that undergo irreversible crosslinking via ionizing radiation‐induced polymerization, the polymer's structure and characteristics being tailored using specific dose rates, doses, linear energy transfer and monomers ratio, in order to achieve the established performance requirements. Here, we demonstrate a covalently bonded 3D hybrid diepoxy‐triacrylic polymer that is chemically and dimensionally stable, intending to use it as a consolidant of highly degraded wooden artifacts in order to mitigate oxygen inhibition from radical chain reactions, to increase chemical and thermal stability, as well as to obtain a stiffer consolidated artifact, therefore more resistant to deformation. Various types of analytical techniques such as Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, Mass Spectrometry or Thermal analysis were performed in order to support our strategy and predictions regarding the synergistic effect given by gamma irradiation‐driven crosslinking through simultaneous cationic and radical chain growth polymerization reaction mechanisms. We achieved a homogenous polymeric formulation and wood‐polymer composite materials with high modulus of elasticity, therefore providing up to a twofold increase in Young's modulus in the consolidated wood, a good chemical resistance to various solvents and outstanding thermal resistance up to 381°C. Consequently, the consolidation methodology, as well as mechanical testing, analytical and morphological characterization of the resulted composite will be discussed. Apart from consolidating cultural heritage wooden artifacts, this synthetic route and impregnation methodology provide opportunities for wood‐polymer composites in a wealth of applications as reinforced wood‐based materials.

Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) Spectroscopy Combined With Deep Learning for Classification of Idiopathic Recurrent Spontaneous Miscarriage (IRSM)

Idiopathic recurrent spontaneous miscarriage (IRSM) is characterized by the repeated losses of two or more clinically detected pregnancies before 24 week of gestation with the cause remaining unknown. We aim to ascertain whether attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy with deep learning (DL) can accurately distinguish IRSM from controls. Endometrial tissue (internal lining of the uterine cavity) was collected from 20 women with IRSM and 20 controls during window of implantation. ATR-FTIR spectroscopy was used to acquire spectra (400–4000 cm−1) from three random locations across each specimen and averaged. Multivariate analysis was used to assess group differentiation. Furthermore, DL classifiers were implemented to predict IRSM. Hierarchical cluster analysis (HCA) demonstrated distinct clustering of the two groups. The principal component analysis (PCA) loading plot indicated contributions from amide I, II and III bands, symmetric methyl (CH3) bending of proteins, lipids, nucleic acids, asymmetric stretching of CH2 due to lipids, collagen, and glucose in discriminating between IRSM and controls. Supervised orthogonal projections to latent structures discriminant analysis (OPLS-DA) exhibited optimized discrimination between the groups. Convolutional neural network (CNN) and variational autoencoder-artificial neural network (VAE-ANN) classifiers exhibited good performance and showed classification accuracy of 94% and 94% and F1 scores (mean of recall and precision) of 95% and 93%, respectively. The optimal area under the receiver operating characteristic curve (AUC) value of both CNN and VAE-ANN was 0.94. ATR-FTIR spectroscopy combined with DL approach is promising for understanding complex disease pathophysiology and enabling early prediction.

Synthesis, structural characterization, computational studies, and antifungal activity of isoniazid derivative

In this work, the isoniazid derivative N',N'''-((1E,1′E)-1,4-phenylenebis(methaneylylidene))di(isonicotinohydrazide) (BISHDZHI) was synthesized and characterized by Nuclear Magnetic Resonance (NMR), Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), Fourier Transform Raman (FT-Raman), and Ultraviolet-Visible (UV–Vis) spectroscopy, and its potential against fungal strains of Candida ssp. was evaluated by in vitro assays. The NMR spectrum confirmed the molecular structure of BISHDZHI. Quantum chemistry computational calculations allowed to obtain the potential energy surface, optimized molecular structure, and to identify all the bands of the Raman, infrared and UV spectra. The data calculated for isoniazid derivative BISHDZHI using the Functional Density Theory (DFT) are in accordance with the experimental values. Our in vitro studies showed that the BISHDZHI compound in association with Fluconazole possesses antifungal action against Candida tropicalis strain, with a reduction of the IC50 24 times to the host. In silico study of ADMET suggested that BISHDZHI has excellent oral bioavailability and metabolic stability, which allows therapeutic action without severe risk to the host. In addition, the molecular docking showed a high interaction potential between the Candida Albicans target. While the molecular dynamics simulations suggested that the BISHDZHI ligand occasioned a minor change in the structure target, indicating more excellent stability than the drug fluconazole.

Synthesis and Characterisation of 4D-Printed NVCL-co-DEGDA Resin Using Stereolithography 3D Printing

The design and manufacturing of objects in various industries have been fundamentally altered by the introduction of D-dimensional (3D) and four-dimensional (4D) printing technologies. Four-dimensional printing, a relatively new technique, has emerged as a result of the ongoing development and advancements in 3D printing. In this study, a stimulus-responsive material, N-Vinylcaprolactam-co-DEGDA (NVCL-co-DEGDA) resin, was synthesised by Stereolithography (SLA) 3D printing technique. The N-Vinylcaprolactam-co-DEGDA resins were initiated by the Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiator. A range of Di(ethylene glycol) diacrylate (DEGDA) concentrations in the NVCL-co-DEGDA resin was explored, ranging from 5 wt% to 40 wt%. The structural properties of the 3D printed objects were investigated by conducting Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the 3D printed samples underwent further characterisation through differential scanning calorimetry (DSC) and swelling analysis. The results revealed an inverse relationship between DEGDA concentration and Tg values, indicating that higher concentrations of DEGDA resulted in lower Tg values. Additionally, the pulsatile swelling studies demonstrated that increasing DEGDA concentration prolonged the time required to reach the maximum swelling ratio. These findings highlight the influence of DEGDA concentration on both the thermal properties and swelling behaviour of 3D printed samples.

Quantitative Applications of ATR-FTIR Spectroscopy with Chemometrics for the Estimation of Amikacin in Amikacin Sulphate Injections

Background: Amikacin belongs to the class of aminoglycoside antibiotics used in the treatment of gram-negative bacterial infections. It is resistant to the aminoglycosides modifying enzymes, making it a clinically effective drug in multidrug-resistant infections. Methods: In this study, a simple Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy was used for the quantification of amikacin in amikacin sulphate injection. The infrared spectra were generated in the spectral range of 4000–667 cm-1. The calibration curve was computed through TQ Analyst Pro edition software, and the partial least square regression analysis found the linearity in the range of 10-60% w/w. Results: The best calibration results were obtained in the spectral region from 1040 to 1020 cm-1 with a correlation coefficient (r2) of 1.000. The residual mean standard error (RMSEC) value was 0.00235. The percent relative standard deviation (%RSD) values for intra-day and inter-day precision were less than 8.0. The percent relative error (%RE) values were calculated and found in between the range of 0.52 to 5.60. The percent recovery of the amikacin estimation was 113.09 ± 4.27(n=3). Conclusion: This validated method is considered a green method, which is suitable for the routine analysis of amikacin in amikacin sulphate injections.

A comprehensive review of synthesis kinetics and formation mechanism of geopolymers.

Geopolymers are synthesized by alkali or acid activation of aluminosilicate materials. This paper critically reviews the synthesis kinetics and formation mechanism of geopolymers. A variety of mechanistic tools such as Environmental Scanning Electron Microscopy (ESEM) and in situ Energy Dispersive X-ray diffractometry (EDXRD), in situ Isothermal Conduction Calorimetry (ICC), in situ Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), 1H low-field Nuclear Magnetic Resonance (NMR) and Isothermal Conduction Calorimetry (ISC), and others and phenomenological models such as the John-Mehl-Avrami-Kolmogorov (JMAK) model, modified Jandar model, and exponential and Knudson linear dispersion models were used to study the geopolymerization kinetics and many mechanisms were proposed for the synthesis of geopolymers. The mechanistic tools and phenomenological models provided new insights about geopolymerization kinetics and formation mechanisms but each of the techniques used possesses some limitations. These limitations need to be removed and new methods or techniques must be developed to overcome these challenges and get more detailed information about all types of geopolymers. The formation mechanism consists of three to four stages such as dissolution of raw materials, polymerization of silica and alumina, condensation, and reorganization. The Si/Al ratio above the Si/Al ratio of reactants is more suitable and it increases the rate or degree of reaction and produces a higher compressive strength geopolymer. The Na/Al ratio of 1, water-to-solid (W/S) ratio of 0.30-0.45, a temperature in the range of 30 °C to 85 °C, and a curing time of 24 hours are the best for the synthesis of geopolymers. The growing demand for geopolymers in various fields requires the development of new advanced techniques for further understanding of kinetics and mechanisms for tailoring the properties of geopolymers for specific applications.

3,4-Dimethoxy phenyl thiosemicarbazone as an effective corrosion inhibitor of copper under acidic solution: comprehensive experimental, characterization and theoretical investigations.

This study investigates the corrosion inhibition potential of 3,4-dimethoxy phenyl thiosemicarbazone (DMPTS) for copper in 1 M hydrochloric acid (HCl) solutions, aiming to disclose the mechanism behind its protective action. Through an integrative methodology encompassing electrochemical analyses-such as weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS)-we quantitatively evaluate the corrosion protection efficacy of DMPTS. It was determined that the optimal concentration of DMPTS markedly boosts the corrosion resistance of copper, achieving an impressive inhibition efficiency of up to 89% at 400 ppm. The formation of a protective layer on the copper surface, a critical aspect of DMPTS's inhibitory action, was characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). These techniques provided empirical evidence of surface morphology modifications and roughness changes, affirming the formation of a protective barrier against corrosion. A significant advancement in our study was the application of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, which identified chemical adsorption as the definitive mechanism of corrosion inhibition by DMPTS. The ATR-FTIR results explicitly demonstrated the specific interactions between DMPTS molecules and the copper surface, indicative of a robust protective adsorbed layer formation. This mechanistic insight, crucial to understanding the inhibitory process, aligns with the protective efficacy observed in electrochemical and surface analyses. Theoretical support, provided by the Quantum Theory of Atoms in Molecules (QTAIM) and quantum chemical computations, further validated the strong molecular interaction between DMPTS and copper, corroborating the experimental findings. Collectively, this research not only confirms the superior corrosion inhibition performance of DMPTS in an acidic setting but also elucidates the chemical adsorption mechanism as the foundation of its action, offering valuable insights for the development of effective corrosion inhibitors in industrial applications.

A Poly(L-Arginine)-Based Electrochemical Sensor for Simultaneous Determination of Uric Acid, Tryptophan, and Hypoxanthine

This study presents the development of an efficient and cost-effective voltammetric sensor for the individual and simultaneous determination of uric acid (UA), tryptophan (Try) and hypoxanthine (HX), the three important biomarkers in the human body. The sensor consists of glassy carbon electrode (GCE) modified with the conducting layer of poly(L-Arginine) (p-Arg) prepared by the electropolymerisation of L-Arginine using cyclic voltammetry. p-Arg modified GCE (p-Arg/GCE) provided well-resolved and improved electrooxidation responses for UA, Try, and HX due to the greater electrocatalytic activity and fast electron transfer ability of the polymer layer. The fabricated sensor was characterised using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Atomic Force Microscopy (AFM), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Electrochemical Impedance Spectroscopy (EIS) and electroactive surface area calculations. Under optimal analytical conditions, determination of the three analytes was possible over wide linear ranges with the limit of detection of 1.97 × 10−8 M, 4.43 × 10−8 M, and 8.44 × 10−9 M, respectively for UA, Try, and HX. Practical utility of the sensor was successfully verified in synthetic urine and blood serum samples and determination of Try and HX was carried out in dietary supplements and commercially available samples of tea and coffee, respectively.

Analysis of protein-protein and protein-membrane interactions by isotope-edited infrared spectroscopy.

The objective of this work is to highlight the power of isotope-edited Fourier transform infrared (FTIR) spectroscopy in resolving important problems encountered in biochemistry, biophysics, and biomedical research, focusing on protein-protein and protein membrane interactions that play key roles in practically all life processes. An overview of the effects of isotope substitutions in (bio)molecules on spectral frequencies and intensities is given. Data are presented demonstrating how isotope-labeled proteins and/or lipids can be used to elucidate enzymatic mechanisms, the mode of membrane binding of peripheral proteins, regulation of membrane protein function, protein aggregation, and local and global structural changes in proteins during functional transitions. The use of polarized attenuated total reflection FTIR spectroscopy to identify the spatial orientation and the secondary structure of a membrane-bound interfacial enzyme and the mode of lipid hydrolysis is described. Methods of production of site-directed, segmental, and domain-specific labeling of proteins by the synthetic, semisynthetic, and recombinant strategies, including advanced protein engineering technologies such as nonsense suppression and frameshift quadruplet codons are overviewed.