Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy Research Articles

Effect of Triterpenoids Betulin and Betulinic Acid on Pulmonary Surfactant Membranes.

The purpose of this work is to examine how triterpenoids betulin (BE) and betulinic acid (BA) affect the thermotropic phase behaviour and bilayer packing in pulmonary surfactant membranes. Therefore, the interaction of these triterpenoids with dipalmitoylphosphatidylcholine (DPPC) bilayers is studied by differential scanning calorimetry (DSC), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and quantum chemical computations with density functional theory (DFT). From DSC data, the effects are more pronounced with BE compared to BA. At BE concentration of 20mol%, the pretransition does not completely disappear and the lamellar phase transition broadens further. There are two indistinguishable peaks in the main phase transition, which may indicate the start of inhomogeneous mixing or phase separation in the gel phase. BA reduces the main transition temperature and almost completely eliminates the pretransition at concentrations of 1-10mol%. Endotherms continue to have a symmetric, broad form that suggests perfect mixing. From ATR-FTIR data, both triterpenoids display the CH2 antisymmetric stretching, C = O stretching, PO2- asymmetric stretching to higher wavenumber in DPPC system. These results indicate an increase in the lateral mobility and dehydration in the polar head group and glycerol-acyl chain interface of DPPC liposomes. From microscopic results, it is found that the addition of high concentration (20mol%) of BE and BA into pure DPPC membranes, single and double planar layers are formed, and the size of the liposomes increases. According to computational studies, the O131-H206 OH group of BE and the P24-O26 head group of DPPC formed a hydrogen bonding of 1.805Å between BE and DPPC in gas phase. This hydrogen bonding is observed between BA and DPPC via the P24-O26 head group of DPPC and the O132-H209 OH group of BA.

Application of MATLAB and SAS Viya AI models towards the elucidation of potential microplastics in the Neuse River Basin

Microplastics (MPLs) are ubiquitous particles derived from degradation from plastic refuse or directly from anthropogenic sources. These particles are present in aquatic environments with potential toxicology across the biosphere. In order to characterize their presence, the Neuse River basin was selected for sampling. However, like many MPLs, spectroscopic characterization can be sullied by weathering processes that obscure the native spectra. Therefore, to enhance MPL identification, Principal Component Analysis (PCA), K-means Clustering (KMC), MATLAB, and SAS Viya’s machine learning (ML) modules were implemented on the Neuse River basin's samples. 18 unknown samples were recorded with attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy against the controls for PCA and KMC: high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and nylon-6 (PA6). Later on, these unknowns were tested against a new set of 900 commercial control samples partitioned by 9 classes for MATLAB and SAS Viya: cellulose acetate (CA), HDPE, LDPE, PP, PS, PVC, PET, polymethyl(methacrylate) (PMMA), and PA6 using µ-FTIR (micro-FTIR) for single-particle discrepancy. Application of MATLAB’s Classification Learner and SAS Viya for Learners software helped aggregate multiple machine learning (ML) models to test for corroboration of predictions with datasets derived from Version 1 (V1), Version 2 (V2), and Version 3 (V3) feature extraction algorithms. Novel feature extractions, based on regressions of discrete data from spectral intensities, in V2 and unique probing of the relationships informing the regressions in V3 showed moderate to moderately high predictor strength, contributing to accuracy increase in V3 according to various predictor strength algorithms in MATLAB. In the test scenario of the strongest version, V3, 63.2% (+ 5.3% from V1) of the models performed very strongly (90% cutoff in accuracy), and 89.5% (+ 0% from V1) of the models performed moderately strongly (80% cutoff in accuracy). The models, coupled with the unsupervised PCA and KMC, indicated microparticle (MP) from Stockinghead Creek in Duplin County, NC; SHR-1b(2), as LDPE. However, the change in corroboration across model types was not significant, according to Kruskal-Wallis (H = 0.555, p = .7577). An ANOVA was performed to see if LDPE incidence was similar across all unknowns, indicating a similar ratio of predictions, excluding NRCP-1 (F = 31.479, p < .0001). While it is unclear if this particle is truly LDPE, the results may suggest that LDPE could be of high presence in the river basin (specifically, PE) when taking into account the predictor set across all versions. Lastly, misclassification was further elucidated for samples “CF-3” and “NRCP-1(2)” which are thought to be extensively-degraded PVC MPLs.

Investigation of meso- and microplastics in commercially sold dried pink shrimp in Ekiti State, South West Nigeria

Microplastics (MPs) are a global problem due to their pervasiveness and possible harm to humans and other living organisms. It has been reported that a wide variety of foods, including seafood, contain microplastics. Dried pink shrimp (Penaeus notialis) popularly called ‘dried crayfish’ is a common delicacy in many Nigerian and West African local recipes. To our knowledge, this is the first study to assess the presence of meso- and microplastics in dried shrimp in Nigeria. From a survey of five popular markets in Ekiti State, South West, Nigeria—Shasha, Oja Oba, Agric Olope, Afao (Ikere), and Oja Isale (Ifaki), 15 samples of sun- and smoke-dried pink shrimp were purchased, and their meso- (5–25 mm) and microplastic (1 to < 5 mm) content was examined. Visual inspection showed that mesoplastic particles were present in all the dried shrimp types examined. A 10% KOH solution was used to digest the samples after they had been weighed. The samples were exposed to density floatation in KI solution, followed by filtration, drying, examination under a stereomicroscope, and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrophotometer. The mean concentration of mesoplastics per 10 g of sample was 2.13 ± 0.56 for sun-dried samples and 3.20 ± 0.90 for smoke-dried samples. Microplastics had a mean concentration of 6.47 ± 1.12 in sun-dried samples and 2.87 ± 0.90 particles/10 g in smoke-dried samples. Generally, the sun-dried shrimp showed a higher prevalence of microplastics than the smoke-dried samples. The ATR-FTIR results revealed the dominance of polyethylene, PE (80%) films and fibres, followed by styrene-butadiene rubber, SBR (12%), natural latex rubber, NLR (5%), and polyvinyl alcohol, PVA (2%). Polymer hazard index (PHI) denoted that PE microplastics had a PHI score of 877.8 classifying them in the hazard category IV which is a “danger” risk. The polymers may directly enter the human body when consumed via dried shrimp and cause health implications.Graphical

Real-Time In Vivo Human Skin Testing Using a Handheld Fourier Transform Infrared Spectrometer with a Three-Bounce Two-Pass Attenuated Total Reflection Interface.

Attenuated total reflection (ATR) Fourier transform infrared spectroscopy (FT-IR) is used to characterize a vast array of materials at the molecular level in various industry types. Here we compare the performance of a portable spectrometer with a novel three-bounce-two-pass (3B2P) ATR scanning interface to the same device with a standard one-bounce (1B) ATR, and to a benchtop spectrometer with a 10-bounce (10B) ATR, in ideal sample-interface conditions and an applied dermatological study setting. In both application settings, the benchtop 10B ATR interface showed the highest signal-to-noise ratio (SNR), however, the novel 3B2P produced a six-fold increase in the sensitivity of the portable spectrometer when analyzing isopropanol and showed the greatest consistency of SNR of all devices when analyzing isopropanol and in vivo skin samples. Spectral data were sourced from a recently undertaken dermatological study involving a cohort of 180 healthy, full-term babies, using both 1B and 3B2P interfaces. Use of the 3B2P interface resulted in a 55% greater successful high-quality spectrum collection rate, compared to the 1B, and showed significantly superior SNR at both observed study time points, i.e., birth (1B: 68.37; 3B2P: 77.37), and at four weeks (1B: 74.53; 3B2P: 80.22). The utility of ATR FT-IR spectrometers as a dermatological clinical tool was also exemplified here, by quantifying the moisture level of newborn skin. By gathering rich spectroscopic data on the molecular structure of the skin, this technique holds great promise for the quantification of skin disease-specific biomarkers.

Construction of δ-FeOOH/NiMn2S4 heterointerface for efficient alkaline oxygen evolution reaction

Alkaline water electrolysis driven by sustainable energy is a viable approach for large-scale green hydrogen production. The development of non-precious metal-based electrocatalysts that combine high activity and stability for the alkaline oxygen evolution reaction (OER) is of great importance. In this work, we design and construct a δ-FeOOH/NiMn2S4/NF heterointerface using a solvothermal/calcination process followed by a facile successive ionic layer adsorption reaction (SILAR) treatment. Experimental tests indicate that the formation of the heterogeneous interface between the δ-FeOOH and the NiMn2S4 creates a good electron transport channel for an efficient electrocatalytic process and improves the charge transfer kinetics. As a result, the prepared δ-FeOOH/NiMn2S4/NF exhibits a low overpotential of 210 mV at 10 mA cm−2 and a low Tafel slope value of 46.6 mV dec−1, and satisfactory stability with a 92.9 % retention after 72 h of OER operation at around 100 mA cm−2. In situ Raman and in-situ attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) tests show that the introduction of δ-FeOOH inhibits the oxidation of Ni2+ to Ni3+ and stabilizes the Ni-S bond to prevent its auto-oxidation, leads to an increase in the electrocatalytic OER activity.

Workability, compressive strength, and efflorescence characteristics of one-part mix alkali-activated circulating fluidised bed combustion fly ash-based mortars

In this study, one-part alkali-activated mortars are formulated using circulating fluidised bed combustion (CFBC) fly ash, derived from lignite (brown coal) combustion, as the precursor, and sodium hydroxide (NaOH) and sodium metasilicate (Na2SiO3) as the solid activators. Experimental findings indicate that an increase in solid activator-to-precursor ratio correlates with improved workability and compressive strength of the mortars. The influence of Na2SiO3-to-NaOH ratio on the compressive strength of the mortars is apparent only in mixes with a high solid activator-to-precursor ratio of 0.4 and 0.5, indicating its relatively lesser significance compared to the solid activator-to-precursor ratio. The mechanism through which an increase in the solid activator-to-precursor ratio improves the compressive strength of the mortars is elucidated using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The results indicate that increasing the solid activator-to-precursor ratio enhances the degree of alkali-activation for fly ash, thereby improving the compressive strength with increasing solid activator-to-precursor ratio.

Forensic Discrimination of Lipstick Stains Using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and Pattern Recognition Techniques

Lipstick stains discovered on objects (such as drinking cups) may be utilized as evidence and/or lead in forensic investigations by chemical analysis. Hence, this study analyzed two brands of lipstick stains' organic composition on paper cups over 0, 24, and 48 h of exposure using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), coupled with pattern recognition techniques of principal component analysis (PCA) and linear discriminant analysis (LDA). Spectral analysis revealed several functional group differences between the two brands of lipstick, viz. Wardah (W) and Silkygirl (S) stains, particularly in the fingerprint region of 1800–650 cm−1. Application of PCA (variance of ≥ 70%) and LDA successfully provided the suitable means for categorically classifying (a) the different brands of lipstick, (b) the male and female volunteers, as well as (c) the different periods of exposure. The fact that the cross-validation correct classification rates for all the LDA models exceeded 90.0%, their suitability for forensic provenance application of lip stains appears statistically supported. Hence, such an approach to combine the non-destructive ATR-FTIR analysis with PCA and LDA is not only easy and cost-effective but also forensically relevant for enabling the data mining process for forensic intelligence.

Enhanced chitosan fibres for skin regeneration: solution blow spinning and incorporation with platelet lysate and tannic acid

Abstract In this study, we developed and characterised enhanced chitosan/polyethylene oxide (PEO) nanofibre scaffolds using solution blow spinning (SBS) for potential application in skin tissue engineering. SBS enabled the efficient and scalable production of fibre matrices with precise morphology control, facilitating the integration of PEO to improve spinnability, 100X the speed of electron spinning. Following fabrication, fibres were subjected to potassium carbonate neutralisation to reduce PEO content, improving chitosan stability in aqueous environments. Characterisation by scanning electron microscopy (SEM) and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) confirmed structural integrity post-neutralisation and the successful incorporation with bioactive additives. Platelet lysate (PL) was incorporated to introduce growth factors, and tannic acid (TA) was added for antibacterial properties and enhanced mechanical stability through potential crosslinking. Mechanical testing showed that the optimised PL- and TA-enriched scaffolds exhibited the highest mechanical performance, with Young’s modulus of 7.0 ± 0.6 MPa, an ultimate tensile strength of 26.4 ± 2.3 MPa, elongation at break of 16.5 ± 1.7%, and toughness of 3.0 ± 0.3 MJ m−3 which is within the range of human skin. At the same time, SEM and ATR-FTIR analyses confirmed the stability and distribution of these functional agents within the fibre network. Biocompatibility tests with normal human dermal fibroblasts (NHDF) indicated low cytotoxicity, appropriate cell adhesion and proliferation over 14 days in culture, suggesting these scaffolds as promising candidates for wound healing and skin regeneration applications.

Multi-method coamorphous systems of lumefantrine with alpha ketoglutaric acid: Comprehensive characterization, biological evaluation and stability analysis.

The Coamorphous systems (CAM) of lumefantrine (LMF) and alpha-ketoglutaric acid (KGA) were developed using three different methods to address the solubility and bioavailability limitations of LMF. Powder X-ray diffraction spectroscopy (PXRD) and differential scanning calorimetry (DSC) confirmed the complete amorphization of the three CAM by the halo pattern and glass transition temperature (Tg), respectively. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR) results indicated that intermolecular interactions existed in the three CAM. Solid-state molecular dynamics simulations revealed the different intermolecular disordered environments present in all three CAM. Solubility analysis showed 14.73×, 12.8× and 9.81× improvement in the liquid-assisted grinding-based coamorphous system (CAM LAG), solvent evaporation-based coamorphous system (CAM SE) and quench-cool-based coamorphous system (CAM QC), respectively, compared to LMF crystalline (LMF CRY). In the in-vitro dissolution experiment 2.63-, 2.16- and 2.17-times increments were observed in CAM LAG, CAM SE and CAM QC compared to LMF CRY, respectively. In-vivo pharmacokinetics study revealed 10.86-, 9.24- and 8.46- folds increments in Cmax of CAM LAG, CAM SE and CAM QC, respectively, compared to LMF CRY. All three CAM illustrated anti-cancer activity in the A549 lung cancer cell line. Molecular dynamics simulation of LMF and KGA with Epidermal growth factor receptor (EGFR), a target for lung cancer treatment, revealed good binding affinity and stability. Stability studies performed under accelerated storage (40 °C/75 % RH) and extreme environmental conditions indicated that all three CAM have good stability. Different methods based prepared CAM have shown different physicochemical properties, bioavailability and stability profiles. These findings suggest that LMF-KGA CAM effectively addresses the solubility and bioavailability challenges of LMF, potentially leading to better therapeutic outcomes in lung cancer treatment.

Synthesis investigation and exploring of new tetraglycidyl bisurea bisphenyl S polyepoxide as an excellent corrosion inhibitory resin for mild steel in 1M HCl environment: Comprehensive approaches

This work reports the synthesis of new epoxy resin namely tetraglycidyl bisurea bisphenyl S (TGBUBS). TGBUBS was characterized through using nuclear magnetic resonance (1H NMR and 13C NMR) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). TGBUBS was investigated as an excellent organic inhibitor for protecting the mild steel from corrosion in 1M HCl solution at different concentrations. Anticorrosion protection behaviors were evaluated and more discussed including different techniques such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and contact angle (CA) measurements. The obtained results showed that the TGBUBS exhibited inhibition efficiencies at lower concentration are 93.19 % (PDP) and 91.21 % (EIS), respectively. Further, PDP measurements indicated that the TGBUBS acted as a mixed-type inhibitor in 1M HCl solution. Furthermore, SEM and EDS analysis showed a significant reduction in the corrosion on the mild steel surface when the inhibitory epoxy resin was present compared to the blank solution (1M HCl). The effectiveness and interactions of the new epoxy resin on the mild steel surface were also predicted using DFT calculations and molecular dynamics (MD) simulations. The theoretical approaches are in agreement with the experiment results.

Enhancing anti-icing efficacy in hybrid polyurethane coatings: Evaluating the significance of molecular weight, chemical structure, and content of PEG/PDMS

This study investigates the advantages of adding polydimethyl siloxane/polyethylene glycol (PEG/PDMS) copolymers to polyurethane coatings, with a particular focus on optimizing anti-icing efficacy. A range of characterization techniques are applied, including attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) analysis, surface roughness measurements, wettability analysis, tensile testing, and ice adhesion measurements, to elucidate the intricate relationships between copolymer molecular weight, chemical structure, and content and their collective effect on the anti-icing properties of the developed coatings. Tailored PEG/PDMS copolymers significantly reduce ice nucleation temperatures and enhance the anti-icing properties of polyurethane coatings. Adding PEG/PDMS copolymers to polyurethane alters the surface roughness, wettability, and mechanical properties of the coatings to improve anti-icing performance. The presence of copolymers decreases ice adhesion strength (<50 kPa), attributed to the formation of a quasi-liquid layer that acts as a lubricant between the ice and the coatings, and delays ice formation. Furthermore, the enhanced durability of copolymer-containing coatings ensures a long-lasting anti-icing effect after multiple icing/de-icing cycles, although some degradation was observed over time. The tailored PEG/PDMS copolymers demonstrate potential for maximizing the anti-icing properties of polyurethane coatings and advancing anti-icing technologies.

Poly(Ionic) Liquid-Enhanced Ion Dynamics in Cellulose-Derived Gel Polymer Electrolytes.

Gel polymer electrolytes (GPEs) are regarded as a promising alternative to conventional electrolytes, combining the advantages of solid and liquid electrolytes. Leveraging the abundance and eco-friendliness of cellulose-based materials, GPEs were produced using methyl cellulose and incorporating various doping agents, either an ionic liquid (1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [Pyr14][TFSI]), its polymeric ionic liquid analogue (Poly(diallyldimethylammonium bis(trifluoromethylsulfonyl)imide) [PDADMA][TFSI]), or an anionically charged backbone polymeric ionic liquid (lithium poly[(4-styrenesulfonyl)(trifluoromethyl(S-trifluoromethylsulfonylimino) sulfonyl) imide] LiP[STFSI]). The ion dynamics and molecular interactions within the GPEs were thoroughly analyzed using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Heteronuclear Overhauser Enhancement Spectroscopy (HOESY), and Pulsed-Field Gradient Nuclear Magnetic Resonance Diffusion (PFG-NMR). Li+ transference numbers (tLi+) were successfully calculated. Our study found that by combining slow-diffusing polymeric ionic liquids (PILs) with fast-diffusing lithium salt, we were able to achieve transference numbers comparable to those of liquid electrolytes, especially with the anionic PIL, LiP[STFSI]. This research highlights the influence of the polymer's nature on lithium-ion transport within GPEs. Additionally, micro supercapacitor (MSC) devices assembled with these GPEs exhibited capacitive behavior. These findings suggest that further optimization of GPE composition could significantly improve their performance, thereby positioning them for application in sustainable and efficient energy storage systems.

2-Amino-6-methylbenzothiazole as corrosion inhibitor for low carbon steel in acidic solution: Experimental and theoretical studies

The corrosion susceptibility of S235 steel samples in 1 M HCl solution, with and without addition of 2-amino-6-methylbenzothiazole (AMBT) was evaluated using weight loss (WL), chronopotentiometry, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PD) techniques. The corrosion inhibition efficiency of AMBT was investigated at 298 to 318 K, with and without addition of 0.5 wt% KI. The highest corrosion inhibition efficiency (i.e. 83.30 %) was achieved upon addition of 5 mM AMBT. PD curve measurements after 24 h immersion revealed that AMBT behaves as a mixed-type inhibitor, predominantly affecting the cathodic corrosion reaction. Thermodynamic calculations showed that AMBT adheres to the Langmuir adsorption isotherm. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) was used to confirm the adsorption of AMBT, while its influence on the morphology of the S235 steel samples was also investigated by scanning electron microscopy (SEM). Density Functional Theory (DFT) calculations, along with Monte Carlo (MC) and Molecular Dynamics (MD) simulations, were employed to investigate AMBT’s corrosion inhibition behaviour at the molecular level. The simulations confirmed that AMBT strongly adsorbs on the Fe(110) surface through a combination of physisorption and chemisorption mechanisms. This study offers detailed insights into AMBT’s effectiveness as a corrosion inhibitor

Effects of Sodium Hypochlorite and Chlorine Dioxide on Human Root Canal Dentine: An ATR-FTIR Spectroscopy Study

Background: It is very important to assess the effects of NaOCl and ClO2 on dentine deproteination because these solutions are in contact with dentine during endodontic treatment and may affect the physical and chemical structure of dentine. Objective: This study aimed to analyze the effects of sodium-hypochlorite (NaOCl) and chlorine-- dioxide (ClO2) on the chemical structure of human dentine by Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy. Method: Fifteen human maxillary incisor roots were cut longitudinally into two parallel dentin discs being approximately 4x4x2 mm in size. 30 samples were randomly allocated to 6 groups treated with 5.25% NaOCl or 0.014% ClO2 (1, 5, or 10 minutes); self-control was used. The effect of solutions on the organic and inorganic components of the radicular dentine surface was analyzed using the amide:phosphate ratio and carbonate:phosphate ratio. The intragroup differences (paired t-test) and intergroup differences (one-way analysis of variance and Tukey’s posthoc test) were analyzed. Result: The intragroup comparisons showed the amide:phosphate ratio to be higher at all times at ClO2. NaOCl caused a decrease in the amide:phosphate ratio at 10 minutes (p&lt;0.05). The intergroup comparison showed that NaOCl caused a greater decrease in amide:phosphate at all times compared to ClO2 (p&lt;0.05). All comparisons demonstrated no significant difference in the carbonate: phosphate ratio (p˃0.05). Conclusion: Considering the results of this study, it is recommended to avoid prolonged exposure to minimize NaOCl-induced dentine deproteination. It should also be taken into account that ClO2 increases the amide:phosphate ratio in radicular dentine, and this effect is advantageous in clinical use for collagen structure, contrary to the negative impact of NaOCl.

A Novel Graphene-Based Nanomaterial for the Development of a Pelvic Implant to Treat Pelvic Organ Prolapse

Graphene is the wonder material of the 21st century, promising cutting-edge advancements in material science with significant applications across all industries. This study investigates the use of a graphene-based nanomaterials (GBNs) ans trade-registered Hastalex®, as novel materials for surgical implants aimed at treating pelvic organ prolapse (POP). This study investigates the mechanical properties and physicochemical characteristics of the material, mainly focusing on its potential to address the limitations of existing polypropylene (PP) implants, which has been associated with numerous complications and banned across multiple countries. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) confirmed the bonding between functionalised graphene oxide (FGO) and the base polymer chain. Hastalex exhibited excellent mechanical properties with 58 N/mm2 maximum tensile strength at break and 701% elongation at break, whilst maintaining its shape with no plastic deformation. These results were comparable to that of sheep pelvic muscular tissue. Hastalex demonstrated its hydrophilic properties from contact angle measurements. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed a uniform plane with surface nanotopography, promoting cell-to-material interaction. The results confirmed the suitability of Hastalex in the development of a new pelvic membrane to treat POP.

Attenuated Total Reflectance Crystal of Silicon for Rapid Nitrate Sensing Combining Mid-Infrared Spectroscopy.

Rapid detection of NO3 --N is critical to address the challenges of food security, environmental degradation, and climate change. Conventional methods for sensing NO3 --N in water demand pretreatments and chemical reagents, which are time- and cost-consuming. Consequently, Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy has been well applied for the determination of NO3 --N. However, the conventional ATR crystals, i.e., zinc selenide (ZnSe) and diamond, showed a weakness in duration or cost since the ZnSe material was relatively soft and diamond was relatively expensive. In this study, comparing with ZnSe-ATR and diamond-ATR, a silicon-based ATR (Si-ATR) accessory was developed and used to explore the applicability and stability for sensing NO3 --N combining mathematic algorithms. It was found that partial least-squares regression (PLSR) showed a good performance comparing with the algorithms of principal component analysis (PCA) and linear regression (LR), and it was recommended for quantifying NO3 --N. For ZnSe-ATR, the residual prediction deviation (RPD) was more than 1.80, the determination coefficient (R 2) was more than 0.7725, and the root-mean-square error (RMSE) was less than 2.73 mg L-1. For diamond-ATR, the RPD was more than 1.76, the R 2 was more than 0.7309, and the RMSE was less than 8.22 mg L-1. For Si-ATR, the RPD was more than 1.42, the R 2 was 0.5198, and the RMSE was less than 11.02 mg L-1. It was confirmed that all three types of ATR could be applied in the quantification of NO3 --N in water for high nitrate concentrations. However, for the quantification of low nitrate concentrations (0-1 mg L-1 NO3 --N), ZnSe-ATR and diamond-ATR acquired the same accuracy, while Si-ATR had a lower accuracy. The pretreatment of Si-ATR-based spectra using the deconvolution algorithm could improve the prediction accuracy compared to water deduction for predicting low NO3 --N. Furthermore, a Si-ATR accessory was developed using Si-ATR, which was reliable for NO3 --N concentration quantification in water with the advantage of its low cost and long durability. Totally, samples with high nitrate concentrations implied a more reliable prediction for all crystals, and comprehensively, ZnSe-ATR was recommended for sensing low nitrate concentrations; diamond-ATR was recommended for samples with strong acid or base corrosion; and for sensing relatively high nitrate concentrations, such as in natural water bodies, Si-ATR was more economical because of its low cost and relatively long use life.

Development of heterostructured ZnCo2O4@Ni-MOF electrode for the asymmetric supercapacitor and electrocatalytic oxygen evolution reaction applications

The stable structure and material combination design significantly improve the performance of electrochemical energy storage and water splitting. In the present study, we developed a ZCO@Ni-MOF core-shell structure over a nickel foam electrode, which is synthesized through a two-step hydrothermal treatment. The developed material is comprehensively analyzed to confirm structural, chemical, electronic, surface, and morphological characteristics using X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscope (SEM), and transmission electron microscope (TEM). Electrochemical investigations using a three-electrode system revealed that ZCO@Ni-MOF demonstrated an impressive specific capacitance of 1800 F g−1 at a current density of 2 A g−1 in a 1 M KOH electrolyte. The electrochemical findings are consistent across various electrochemical techniques. Furthermore, in-depth studies regarding p-n junction formation, interlayer spacing, and reaction kinetics studies are briefly analyzed with Mott-Schottky, Ex-situ XRD, and operando impedance studies. Moreover, an asymmetric supercapacitor (ASC) is assembled with ZCO@Ni-MOF as the positive electrode and activated carbon as the negative electrode in a Swagelok cell. This configuration demonstrated an energy density of 13.6 Wh kg−1 at a power density of 225 W kg−1. The ASC exhibited performance by retaining 91 % of its initial capacity even after 1500 cycles. For practical demonstration, two ASCs are fabricated and assembled in series to light up an LED, and the light-up duration is analyzed. For the oxygen evolution reaction (OER) study, the ZCO@Ni-MOF-based electrode exhibited activity with a lower overpotential of 340 mV (50 mA cm−2) in an alkaline environment and was responsible for stability for about 10 h. This combination reiterates the promising material aspects in energy storage and conversion devices, instilling hope for its potential applications.

Tuning oxygen vacancy for efficient CO2 electroreduction over CeO2 supported SnO2

CO2 electroreduction is favorable in neutral or alkaline aqueous solutions, where H2O serves as the proton source, suffering from sluggish dynamics. Herein, we synthesize a series of SnO2-CeO2 with different oxygen vacancy (Ov) concentration, regulating the H2O dissociation, to synchronize with the CO2 reduction. The optimal SnO2-CeO2 catalyst, with a moderate Ov concentration, exhibits a formate Faradic efficiency of nearly 93% and maintains for more than 46 h at a current density of 100 mA/cm2. The catalyst with lower Ov concentration results in weak H2O dissociation, thus enhancing the energy barrier of *OCHO generation, while higher Ov concentration leads to excessive proton, exacerbating the hydrogen evolution reaction (HER), as supported by DFT calculation and in situ attenuated total reflection-Fourier transform infrared spectra (ATR-FTIR). This study underscores the significance of Ov concentration in determining the ability of water dissociation over supported electrocatalysts, providing valuable insights for the development of more efficient electrocatalyst.

Challenges of analytical methods for the characterization of microsamples from David Alfaro Siqueiros mural painting.

This study presents the analysis of seven microsamples from Untitled Mural 3, painted by David Alfaro Siqueiros between 1964 and 1972. The mural has never been restored, therefore preserving the materials used by the artist. The microsamples were analyzed using a combination of techniques: optical microscopy (OM), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), micro-Fourier transform infrared spectroscopy (micro-FTIR) with reflection mode, and high-resolution nuclear magnetic resonance (NMR) spectroscopy. In this work, compounds common to those identified in the analysis of the contemporary mural Trazos de composición piramidal composition were identified, such as acrylic and nitrocellulose binders, titanium white and iron red oxide as pigments, and DEHP as a plasticizer. Unexpectedly, polyvinyl acetate (PVAc) and different nitrocellulose monomers were identified, in addition to chrome yellow instead of ochre, and a predominance of quartz, asbestos, and talc as fillers, instead of carbonates. The study confirmed that Siqueiros used multiple binders in successive layers in no apparent order, providing valuable insights into his artistic techniques. The research also proved an efficient methodology for studying very small and complex samples.

Enhanced corrosion protection of copper in saline environments using bio-nanocomposite coatings based on chitosan and chitosan Schiff base

An in-depth study focuses on developing new environmentally friendly bio-nanocomposites, by incorporating SrTiO3 (STO) ceramic nanoparticles into matrices of chitosan and its derivatives, aiming to use them as protective coatings against corrosion. The various stages of this study include the cross-linking of chitosan, the synthesis of Schiff base chitosan, the cross-linking of Schiff base chitosan, and the preparation of nanocomposite coatings. The coatings' structure and composition were analyzed using different methods, including Fourier Transform Infrared Spectroscopy - Attenuated Total Reflectance (FTIR-ATR), X-ray Diffraction (XRD), Transmission Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (TEM-EDX), and Scanning Electron Microscopy (SEM). In addition, Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PDP) measurements were carried out to assess the inhibitory efficacy of chitosan crosslinked with epichlorohydrin (Cs-Ep), epichlorohydrin-crosslinked chitosan-salicylaldehyde Schiff base (CS-S-Ep) and CS-Ep-STO and CS-S-Ep-STO nanocomposite coatings, as well as the long-term protection durability of CS-S-Ep-STO. These techniques revealed a significant reduction in corrosion current density after chemical modification of chitosan and incorporation of SrTiO3 (STO) nanoparticles into CS-Ep and CS-S-Ep matrices, confirming a notable improvement in the inhibitory efficiency of these coatings against copper corrosion in a saline environment. Computational modeling methods like Density Functional Theory (DFT), Molecular Dynamics (MD), and Monte Carlo (MC) simulations reinforced these results by demonstrating efficient adsorption of CS-S-Ep-STO nanocomposites on metal surfaces through the interaction with heteroatoms present in the functional groups (-C=N-, -C-O-, -OH) and STO nanoparticles. The present study's findings provide key information for developing innovative protective coatings, highlighting the potential of chitosan-based nanocomposites and derivatives, particularly with SrTiO3 incorporation, in mitigating metal surface corrosion in aggressive environments.