Fourier Transform Infrared Spectroscopy Analysis Research Articles

Changes in wood durability due to leaching of biologically active substances (extractives) resulting from weathering

Wood durability is vital for its long-term performance in outdoor applications, influenced by various factors. This study investigates the impact of leaching biologically active substances due to weathering on wood durability. The research covers multiple wood species and treated wood subjected to natural and accelerated weathering. Chemical analysis includes extraction, spectrophotometry (UV-Vis), chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray fluorescence spectroscopy (XRF). Additionally, fungal and wetting ability tests were conducted. Results indicate significant extractive leaching during weathering. However, the part of the extractives with the highest biological activity, i.e. the phenolic compounds, were slightly less susceptible to leaching than other extractives. While FTIR analysis suggests minimal degradation of other wood compounds, accelerated weathering induced notable extractive loss. Weathering adversely affected inherent durability and wetting ability, leading to reduced relative resistance dose according to the Meyer-Veltrup model. Black locust exhibited the least reduction, while pine heartwood showed the highest decrease in resistance dose. Paste tests revealed fungicidal components' contribution to wood durability, indicating its multifaceted nature. This comprehensive study sheds light on the intricate dynamics between weathering, extractive leaching, and wood durability, offering insights crucial for optimizing wood treatment and preservation methods in outdoor environments.

Production of Polyvinyl Alcohol/Amoxicillin – Chitosan/Collagen Hybrid Bilayer Membranes for Regeneration of Gingival Tissues

AbstractPeriodontal diseases, if untreated, can cause gum recession and tooth root exposure, resulting in infection and irreversible damage. Traditional treatments using autologous grafts are painful and often result in postoperative complications. Scaffolds offer a less invasive alternative, promoting cell proliferation and healing without additional surgery, thus enhancing comfort for patients and doctors. This study developed Chitosan (Chit)/Collagen (Col) film surfaces and drug‐loaded Polyvinyl Alcohol (PVA)/Amoxicillin (AMX) nanofibers using solvent casting and electrospinning methods, respectively. The surfaces are characterized by scanning electron microscopy (SEM), mechanical testing, Fourier Transform Infrared Spectroscopy (FTIR), and differential scanning calorimetry (DSC). Biocompatibility and antimicrobial properties are assessed using NIH/3T3 fibroblast cells and bacterial cultures. SEM images confirmed the structural integrity of AMX‐loaded 13% PVA nanofibers, while FTIR analysis validated the compositional integrity of PVA/AMX nanofibers and Chit/Col film hybrid surfaces. Cell studies showed over 90% viability for Chit/Col film + PVA/AMX nanofiber hybrid bilayer membranes, confirming their biocompatibility. The antimicrobial assessment indicated that the Chit/Col film + PVA/AMX (0.2%) nanofiber hybrid bilayer membrane exhibited superior efficacy against Streptococcus mutans. These findings suggest that this hybrid bilayer membrane can enhance cell growth, promote proliferation, and enable controlled drug release, offering significant promise for regeneration of gingival tissues.

Modification of Poly(3-Hydroxybutyrate) with a Linear Polyurethane Modifier and Organic Nanofiller—Preparation and Structure–Property Relationship

The growing demand for products made of polymeric materials, including the commonly used polypropylene (PP), is accompanied by the problem of storing and disposing of non-biodegradable waste, increasing greenhouse gas emissions, climate change and the creation of toxic products that constitute a health hazard of all living organisms. Moreover, most of the synthetic polymers used are made from petrochemical feedstocks from non-renewable resources. The use of petrochemical raw materials also causes degradation of the natural environment. A potential solution to these problems is the use of biopolymers. Biopolymers include biodegradable or biosynthesizable polymers, i.e., obtained from renewable sources or produced synthetically but from raw materials of natural origin. One of them is the poly(3-hydroxybutyrate) (P3HB) biopolymer, whose properties are comparable to PP. Unfortunately, it is necessary to modify its properties to improve its processing and operational properties. In the work, hybrid polymer nanobiocomposites based on P3HB, with the addition of chain, uncross-linked polyurethane (PU) and layered aluminosilicate modified with organic salts (Cloisite®30B) were produced by extrusion process. The introduction of PU and Cloisite®30B to the polymer matrix (P3HB) influenced the processing parameters beneficially and resulted in a decrease in the extrusion temperature of more than 10 °C. The influence of the simultaneous addition of a constant amount of PU (10 m/m%) and the different amounts of nanoadditives (1, 2 and 3 m/m%) on the compatibility, morphology and static mechanical properties of the resulted nanobiocomposites were examined. The component interactions by Fourier transformation infrared spectroscopy (FTIR) analysis, nano- and microscale structure studies using small-angle X-ray scattering (SAXS) and morphology by scanning electron microscopy (SEM) were carried out, and the hardness and tensile strength of the obtained polymer nanobiocomposites were determined. FTIR analysis identified the compatibility of the polyester matrix, PU, and organomodified montmorillonite, the greatest being 3 m/m% Cloisite30B content. The addition of PU to the polyester elasticizes the material and decreases the material’s strength and ductility. The presence of nanoclay enhanced the mechanical properties of nanobiocomposites. The resulting nanobiocomposites can be used in the production of short-life materials applied in gardening or agriculture.

Comparative analysis of biofilm structures in Salmonella Typhimurium DMC4 strain and its dam and seqA gene mutants using Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy methods.

It is well-established that the dam and seqA genes act in the biofilm production in Salmonella. However, the molecular basis underlying this activity remains unexplored. This study aims to address this gap in the literature. In this study, comparative Fourier Transform Infrared (FT-IR) Spectroscopy and Raman spectral analyses were conducted to investigate the molecular basis of decreases in swimming, swarming motility, and biofilm characteristics observed in the dam and seqA gene mutants of S. Typhimurium DMC4 wild-type strain. The comparative analysis revealed a pronounced reduction in proteins, lipids, carbohydrates, and nucleic acids within the biofilm structures of mutant strains. These findings confirm that these macromolecules are crucial for the integrity and functionality of biofilm structures. FT-IR analysis showed that while amide-I bands decreased in the biofilm structures of mutant strains, amide-II bands increased compared to the wild-type strain. Similarly, Raman analyses indicated an increase in amide-IV bonds and a decrease in amide-V bonds. The parallelism between FT-IR and Raman spectral analysis results, particularly regarding amide I, amide V, amide II, and amide IV bands, is noteworthy. Additionally, these findings may lead to the development of markers for rapidly diagnosing transitions from planktonic to biofilm form in Salmonella. The substantial decrease in β-glucans and lipids, including cellulose, within the biofilm matrix of mutant strains highlights the critical role these polymers play in swimming and swarming motility. Given the clinical and industrial importance of Salmonella biofilms, it is crucial to develop strategies to prevent biofilm formation and identify target molecules that can inhibit biofilm formation. The results of our study suggest that β-glucans and amides are essential targets in the effort to combat Salmonella biofilms.

Experimental and modelling analysis of waste material-based geopolymer concrete incorporated with crumb rubber particles

Rubberized geopolymer concrete (RuGPC) emerges as an eco-friendly alternative to conventional concrete, significantly reducing greenhouse gas emissions. This study investigates the use of steel slag (SS) in varying proportions (30 %, 35 %, and 40 %) as a replacement for ground granulated blast furnace slag (GGBS) in geopolymer concrete, with crumb rubber (CR) replacing crusher dust (CD) as fine aggregate due to its increasing demand. The research focuses on understanding the impact of aluminosilicate materials on the mechanical, thermal, and microstructural properties of geopolymer concrete cured at 60°C. Advanced characterization techniques, including Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR), were employed. SEM and EDX analyses revealed that the microstructural properties of GGBS and SS materials, mainly Na/Si, Si/Al, H₂O/Na₂O, and Na/Al ratios, significantly influence RuGPC performance through gel formation. FTIR analysis indicates a shift in the stretching vibrations of GGBS and SS to lower wavenumbers due to geopolymerization changes. XRD results show the formation of C-S-H gel at around 27–30° 2theta, attributed to increased GGBS and SS content. Despite efforts to incorporate CR into geopolymer matrices, challenges in mitigating strength degradation persist. To address this, a predictive model was developed to understand the key factors affecting RuGPC performance. Six machine learning techniques—M5P (pruned and unpruned), random forest, random tree, linear regression, and support vector machine with various kernels (PUK, RBF, PK, and NPK), and artificial neural network (ANN)—were employed to predict the physical and thermal behavior of RuGPC. The analysis identified ANN-based models as the most effective. Sensitivity analysis highlighted the grade of rubber and the CR replacement percentage by volume of CD as the most influential parameters determining RuGPC compressive strength, density, and thermal conductivity. Moreover, The economic analysis revealed that RuGPC mixtures were 1.2–11.61 % more cost-effective than OPC concrete. These findings underscore the importance of predictive model development in optimizing RuGPC properties for practical applications, offering valuable insights for decision-making processes.

Solvation phenomena in ternary system tetramethylurea-methylacetamide-water: Insights from volumetric, compressibility and FTIR analysis

The properties of the ternary systems N,N,N',N'-tetramethylurea - N-methylacetamide - water were investigated using Fourier-transform infrared spectroscopy (FTIR), volumetric and compression measurements. Densities and sound velocities were determined in order to obtain the apparent molar volumes (VΦ) and apparent molar isentropic compressions (▪S,Φ). These values were then extrapolated to infinite dilution. Additionally, interaction parameters were calculated from the McMillan-Mayer theory. The studies were conducted at 288.15, 298.15, and 308.15 K, at atmospheric pressure (0.1 MPa). The concentration ranges of N-methylacetamide were 2, 4, 6, and 8 moles per kilogram of pure water, and for N,N,N',N'-tetramethylurea from 0 to around 0.35 moles per kilogram of solvent. Discrete changes in isentropic compression were observed. This is the result of the alignment of plots of ▪S,Φ0 as a function of NMA concentration. The results for N,N,N',N'-tetramethylurea were compared with analogous data for the system containing n-butylurea, which is an isomeric compound but exhibits different hydration behaviour. Additionally, large volumetric interaction coefficients were observed, indicating strong interactions between urea derivatives and NMA. This suggests the possibility of strong interactions between protein destabilizers and the protein backbone, differing from those observed for protein structure stabilizers. The observation contributes to understanding the mechanism of osmolyte action and their influence on protein stability.

Optimization of Microcrystalline Cellulose Production from Brewer’s Spent Grain by Acid Hydrolysis

Brewer’s spent grain (BSG) is the main insoluble solid by-product of the brewing industry. To add value to this non-wood material, microcrystalline cellulose (MCC) was prepared from BSG by alkaline pretreatment, bleaching, and subsequent acid hydrolysis to produce non-wood MCC. This study aimed to optimize MCC production using a statistical design (Box-Behnken) with three factors at three levels: acid concentration (0.5–1.5 M), hydrolysis time (70–90 min) and hydrolysis temperature (55–65 °C), to achieve the maximum yield and crystallinity of MCC derived from BSG. Results from 17 experimental runs revealed that the hydrolysis condition of 0.63 M HCl for 70 min at 61 °C yielded the highest output of 15% with a crystallinity index of 60%. The chemical structures and characteristics of MCC derived from BSG were verified by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction analysis (XRD). FT-IR analysis showed that the major wavenumbers of lignin and hemicellulose after the chemical processes (1500 cm–1 and 1735 cm–1) decreased by 21.40% and 4.60%, respectively. The XRD chromatogram revealed that the XRD characteristic peaks were sharper after the chemical treatments, indicating an increase in cellulose crystallinity due to removing lignin and hemicellulose. The crystallinity index of MCC derived from BSG ranged from 55–64%, which is comparable in quality to commercial pharmaceutical MCC, Avicel® PH-101 (67.37%). These results demonstrated that MCC from BSG was successfully prepared by acid hydrolysis under optimized conditions. BSG proved a viable non-wood source for preparing MCC for application in the pharmaceutical and nutraceutical industries.

Multisite Pt/H2Ti2O5-TiO2 catalyst for formaldehyde oxidation

The development of multisite catalysts that simultaneously satisfy compositional, spatial arrangement and functional requirements remains a significant challenge. Herein, we report a supported Pt catalyst on surface hydroxyl- and oxygen-vacancy-rich H2Ti2O5/TiO2 composite nanotubes for formaldehyde (HCHO) oxidation. Our study demonstrates that H2Ti2O5/TiO2 nanotubes can be prepared by a hydrothermal method and in particular, using Na2[Pt(OH)6] as a metal precursor yields ultrasmall and uniformly distributed Pt nanoparticles on the nanotube surface. In situ diffuse reflectance infrared Fourier transform spectroscopy analyses reveal that HCHO oxidation over the Pt/H2Ti2O5-TiO2 catalyst occurs via a cooperative catalysis mechanism: Pt facilitates the splitting of O2, surface hydroxyl group on H2Ti2O5 serves as HCHO adsorption site and oxygen vacancy on the TiO2 surface promotes the dissociation of H2O to generate active OH species. Consequently, the Pt/H2Ti2O5-TiO2 catalyst exhibits an impressively high mass-specific reaction rate of 118.0 μmol gPt−1 s−1 and excellent stability, outperforming previously reported HCHO oxidation catalysts.

Ferric ions crosslinked hyaluronic acid beads: potentials for drug delivery use

Introduction and purpose Despite the attractive properties of hyaluronic acid (HA), The preparation of HA beads is still challenging. This article reports the preparation of pH-sensitive gel HA beads. The ionic gelation method was used to prepare the HA gel beads using ferric ions. This cross-linking type is based on forming coordination bonds, which enhance the mechanical properties of the prepared beads. Methods The developed beads were characterized using Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) examined the bead’s morphology. Furthermore, the potential of HA gel beads as an oral drug delivery system was investigated using metformin as a hydrophilic model drug. The entrapment efficiency and in vitro, release, and release kinetics were evaluated. The crosslinking density and HA concentration effect on drug release and bead swelling capacity under pH 1.2 and 7.4 were also investigated. Results The entrapment efficiency of metformin in HA beads was found to be 79.56 ± 3.89%. FTIR analysis indicated the ionic interaction between ferric ions and the carboxylic groups on the HA molecule. At the same time, there was no substantial interaction between metformin and the polymeric bead. Morphological evaluation and DSC analysis suggested the successful incorporation of metformin within the beads. The in vitro drug release evaluation showed pH-dependent extended release where the release kinetics followed the first-order mathematical model. Conclusions This study provides a value-added formulation with the potential for drug delivery use, which can be further investigated for biomedical applications.

Utilizing foxtail millet husk waste for sustainable new bioplastic composites with enhanced thermal stability and biodegradability

Foxtail millet husk (FMH) is a byproduct that is not suitable for consumption and is often discarded as solid waste. However, it can be used as a raw material to develop novel bioplastic composites that transform agro-based leftovers into value-added goods. Herein, new bioplastic composites were developed from poly(lactic acid), poly(butylene adipate-co-terephthalate) and FMH based granules by Injection Molding. The required granules were generated via a solvent evaporation method. The resulted bioplastic composites were analyzed for their morphologies, mechanical properties, crystal structures, thermal stability, and melting and crystallization behaviors using various techniques, such as scanning electron microscopy, universal testing machine, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. Expressly, chemical bonding between FMH fibers and poly(lactic acid)/poly(butylene adipate-co-terephthalate) PLA/PBAT was confirmed through Fourier Transform infrared spectroscopy analysis. The inclusion of FMH lowered the impact strength of the PLA/PBAT combination, which was confirmed by mechanical analysis. Morphological findings confirmed that the PLA/PBAT combination had FMH aggregation. DSC thermograph revealed negligible differences in glass transition and melting temperatures of PLA/PBAT blend with and without FMH. The thermogravimetry results exhibit that the FMH can improve bioplastic thermal stability. The addition of FMH improved the biodegradability of the PLA/PBAT bioplastic composites. Overall, FMH waste can be repurposed for bioplastic composites with enhanced thermal stability and biodegradability. This reduces solid waste from agricultural practices and creates eco-friendly products. Further research could lead to more sustainable alternatives.

Effect of MoS2 Morphology on the Photocatalytic Degradation of 4-Nitrophenol to Aminophenol

Nitroaromatic compounds are frequently detected as contaminants in industrial or agricultural wastewaters. Wastewater discharge contributes to nitrophenol pollution of the aquatic environment. Toxicity and carcinogenicity of 4-nitrophenol cause serious impact on water bodies. The present study is devoted to investigates the photocatalytic degradation of p-nitrophenol to aminophenol by MoS2 photocatalyst. MoS2 nanoparticles were synthesized via a hydrothermal process and further characterized by using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), High resolution transmission microscopy (HRTEM), UV-Visible spectroscopy, Brunauer–Emmett–Teller (BET), and X-ray photoelectron spectroscopy (XPS). X-ray analysis revealed the presence of 2H phase of MoS2 and XPS analysis determined its various oxidation states. Fourier Transformation Infra-Red Spectroscopy (FTIR) and Thermogravimetric analyses (TGA) were used to study the functional group and thermal stability. UV-Visible spectroscopy was used to study the degradation of 4-nitrophenol and reaction kinetics. Investigation results showed a significant effect of nanosheets over nanoflower morphology for degradation efficiency of 4 nitrophenol to aminophenol under natural Sunlight.

Gamma irradiation for Cultural Heritage conservation: Comparison of the side effects on new and old paper

Ionizing radiations, commonly applied as diagnostic tools in Cultural Heritage (CH) field, are also proving effective for eliminating biodeteriogens (insects, fungi, bacteria and molds) responsible for the degradation of CH artifacts and often harmful for restorers, archivists and librarians. The use of ionizing radiations, such as gamma rays, for CH treatments is spreading in many countries. However, some CH operators remain resistant due to insufficient knowledge about the potential physico-chemical modifications (secondary effects) induced by radiation. This work aims to investigate and compare the effects of irradiation parameters (such as absorbed dose and dose rate) on old paper samples and new pure-cellulose paper, chosen as a reference model material. Absorbed doses up to 8 kGy have been used, as these values are commonly agreed upon for the preservation treatment of CH artifacts and are generally effective for biodeteriogens removal. Optimizing irradiation conditions helps to minimize secondary effects (such as oxidation, depolymerization or color changes), thereby increasing the reliability of the process and boosting confidence among CH operators. The secondary effects were analyzed using various physico-chemical characterizations (Fourier Transform Infrared spectroscopy, Raman microscopy, viscosimetric and colorimetric analysis) on old and new paper samples. The results indicate varying behaviors, correlated with paper composition, sample age and irradiation parameters, towards gamma radiation. This groundbreaking study not only confirms the efficacy of gamma irradiation treatments but also provides essential data that will aid in the development of optimized best practice protocols and guidelines for non-destructive and minimally destructive methods applied to real case studies and treatments.

Processing of Reduced Graphene Oxide Reinforced Ultra High Molecular Weight Polyethylene for Orthopedic Implants

Ultra-high molecular weight polyethylene (UHMWPE) has been used as a bearing material in total joint replacements due to its excellent mechanical properties and biocompatibility. The acetabular cup in total hip replacement and the tibial component in total knee replacement is widely fabricated from UHMWPE. The use of UHMWPE in total joint replacements is well established, and the goal is to improve its mechanical properties, wear resistance, and oxidation resistance. The quality and life span of the artificial joints can be further increased by enhancing the relevant mechanical properties of UHMWPE. The addition of filler material to UHMWPE is an effective way to enhance its relevant properties. In this study, relevant properties of UHMWPE were enhanced by incorporating an appropriate filler. Reduced Graphene Oxide (rGO) was selected as a filler material as it improves mechanical properties, wear resistance, toughness, and thermal stability. Graphene oxide (GO) was synthesized by Modified Hummer’s Method (MHM), and it was thermally reduced to obtain rGO. The synthesized GO was characterized by Fourier Transform Infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) which confirmed the accurate synthesis. The reduction of GO was validated by the disappearance of (OH) broad peak in the FTIR analysis. The rGO/UHMWPE nanocomposite was prepared by adding 0.7 wt.% of rGO employing the solvent mixing method. The morphology of the composite was validated by Scanning Electron Microscopy (SEM). Tensile and Izod Impact tests were performed on the samples which showed an increase in tensile strength of 33.2% and the impact strength increased by 140.5%. The rGO/UHMWPE nanocomposite with greater tensile and impact strength is an excellent candidate to produce orthopedic implants with superior properties.

Catalytic reduction, antibacterial, and antioxidant activities of green synthesized silver nanoparticles using Coccinea grandies (L) Voigt leaf extract

In this study, silver nanoparticles (AgNPs) were synthesized using the aqueous extract of Coccinia grandis (L) Voigt leaf (CGL) extract using microwave irradiation method and the structure was elucidated by various techniques such as UV–Visible spectroscopy, Fourier transformation infrared spectroscopy (FT-IR), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive x-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HR-TEM). The UV–visible spectroscopy confirmed the formation of AgNPs and SPR band appear at 420 nm. FT-IR analysis indicated the presence of –OH and –NH functional groups from secondary molecules of CGL capping the AgNPs surface. HR-TEM revealed spherical aggregates with an average size of 29.4 nm. EDX confirmed the presence of elemental silver. XRD analysis showed that the AgNPs had a face-cantered cubic (FCC) crystal structure. The CGL-AgNPs were used as a heterogeneous catalyst to reduce RhB and CR dyes from aqueous solutions in the presence of sodium borohydride (NaBH4). The results showed that greater than 95 % of catalytic reduction can be accomplished within 9 min. The biosynthesized AgNPs demonstrated notable antioxidant activity (82.89 % in the DPPH assay) and antibacterial activity with a Zone of inhibition ranging from 9 to 11 mm. These findings suggest that CGL can be used to synthesize new, cost-effective AgNPs using an environmentally friendly approach.

Aluminate-activated nano-SiO2 for enhancing water vapor barrier properties in polymers films: A safe and effective strategy

In this work, a series of nanocomposite films composed of polylactic acid (PLA), poly (butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS), nano-SiO2 activated by aluminate for different times were developed to enhance water vapor barrier properties. The physiochemical and thermal properties of the films were characterized. In addition, total and aluminum migration from the films was monitored, and non-targeted screening was performed to evaluate the potential safety of the composite films. Fourier Transform infrared spectroscopy analysis indicated that the nano-SiO2 was successfully activated by aluminate. Differential scanning calorimetry analysis indicated that incorporation of the activated nano-SiO2 slightly reduced the glass transition temperature (from 54 to 51 °C) and increased the crystallinity degree (from 6.9 % to 11.1 %) of PLA. Incorporation of 0.4 % nanofillers was found to give the highest crystallinity. Thermogravimetric analysis showed that the thermal stability of the PLA/PBAT/PBS films did not change significantly after adding the activated-nano-SiO2. However, the incorporation of these nanofillers did increase the interfacial roughness and crystallinity degree of the films, thereby reducing the water vapor permeability by around 30 %. Erucamide was detected in the composite films after exposure to food simulants, however, the films containing the nanofillers still met European Union safety standards. In summary, the nanofiller-loaded polymer films developed in this study were shown to be safe and have high water barrier properties, which means they may be suitable for application in the food, cosmetic, personal care, pharmaceutical, and agrochemical industries.

Thermal Decomposition and Kinetic Analysis of Amazonian Woods: A Comparative Study of Goupia glabra and Manilkara huberi

This study presents a detailed analysis of the thermal degradation and kinetic behavior of two Amazonian wood species, Goupia glabra (cupiúba) and Manilkara huberi (maçaranduba), using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR-ATR), and direct infusion mass spectrometry (DIMS). Wood samples were subjected to controlled heating rates of 20, 40, and 60 °C/min from 25 to 800 °C under an argon atmosphere. TGA revealed moisture evaporation below 120 °C, with hemicellulose degradation occurring between 220 and 315 °C, cellulose decomposition between 315 and 400 °C, and lignin breakdown over a broader range from 180 to 900 °C. The highest rate of mass loss occurred at 363.99 °C for G. glabra and 360.27 °C for M. huberi at a heating rate of 20 °C/min, with shifts to higher temperatures at faster heating rates. Activation energies were calculated using Arrhenius and Kissinger models, yielding values between 53.46–61.45 kJ/mol for G. glabra and 58.18–62.77 kJ/mol for M. huberi, confirming their stable thermal profiles. DSC analysis identified a significant endothermic peak related to moisture evaporation below 100 °C, followed by two exothermic peaks. For G. glabra, the first exothermic peak appeared at 331.45 °C and the second at 466.08 °C, while for M. huberi, these occurred at 366.41 °C and 466.08 °C, indicating the decomposition of hemicellulose, cellulose, and lignin. Enthalpy values for G. glabra were 12,633.37 mJ and 18,652.66 mJ for the first and second peaks, respectively, while M. huberi showed lower enthalpies of 9648.04 mJ and 14,417.68 mJ, suggesting a higher energy release in G. glabra. FTIR-ATR analysis highlighted the presence of key functional groups in both species, with strong absorption bands in the 3330–3500 cm−1 region corresponding to O-H stretching vibrations, indicative of hydroxyl groups in cellulose and hemicellulose. The 1500–1600 cm−1 region, representing aromatic C=C vibrations, confirmed the presence of lignin. Quantitatively, these results suggest a high content of cellulose and lignin in both species. DIMS analysis further identified polyphenolic compounds and triterpenoids in M. huberi, with major ions at m/z 289 and 409, while G. glabra showed steroidal and polyphenolic compounds with a base peak at m/z 395. These findings indicate the significant presence of bioactive compounds, contributing to the wood’s resistance to microbial degradation. This comprehensive thermal and chemical characterization suggests that both species have potential industrial applications in environments requiring high thermal stability.

Understanding the roles of Brønsted/Lewis acid sites on manganese oxide-zeolite hybrid catalysts for low-temperature NH3-SCR

Although metal oxide-zeolite hybrid materials have long been known to achieve enhanced catalytic activity and selectivity in NOx removal reactions through the inter-particle diffusion of intermediate species, their subsequent reaction mechanism on acid sites is still unclear and requires investigation. In this study, the distribution of Brønsted/Lewis acid sites in the hybrid materials was precisely adjusted by introducing potassium ions, which not only selectively bind to Brønsted acid sites but also potentially affect the formation and diffusion of activated NO species. Systematic in situ diffuse reflectance infrared Fourier transform spectroscopy analyses coupled with selective catalytic reduction of NOx with NH3 (NH3-SCR) reaction demonstrate that the Lewis acid sites over MnOx are more active for NO reduction but have lower selectivity to N2 than Brønsted acids sites. Brønsted acid sites primarily produce N2, whereas Lewis acid sites primarily produce N2O, contributing to unfavorable N2 selectivity. The Brønsted acid sites present in Y zeolite, which are stronger than those on MnOx, accelerate the NH3-SCR reaction in which the nitrite/nitrate species diffused from the MnOx particles rapidly convert into the N2. Therefore, it is important to design the catalyst so that the activated NO species formed in MnOx diffuse to and are selectively decomposed on the Brønsted acid sites of H-Y zeolite rather than that of MnOx particle. For the physically mixed H-MnOx+H-Y sample, the abundant Brønsted/Lewis acid sites in H-MnOx give rise to significant consumption of activated NO species before their inter-particle diffusion, thereby hindering the enhancement of the synergistic effects. Furthermore, we found that the intercalated K+ in K-MnOx has an unexpected favorable role in the NO reduction rate, probably owing to faster diffusion of the activated NO species on K-MnOx than H-MnOx. This study will help to design promising metal oxide-zeolite hybrid catalysts by identifying the role of the acid sites in two different constituents.

Biofabricated silver nanoparticles from Calotropis procera: A potential antimicrobial solution against pathogenic bacteria

Calotropis procera has the potential as a traditional medicinal plant that offers a diverse array of healing treatments. It was used in conventional medicine to remedy several ailments, including diarrhea and snakebites. This study examines the antibacterial properties of silver nanoparticles derived from the floral and latex components of C. procera. The nanoparticles were tested for their effectiveness against Gram-negative and Gram-positive bacterial strains. For characterization, the synthesized nanoparticles underwent thorough analysis using UV spectroscopy, fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). After the reduction process, the FTIR analysis revealed that some functional biomolecules found in plants form a coating on the nanoparticles, serving as organic agents that stabilize the nanoparticles. The size of nanoparticles analyzed with SEM falls in the 30 to 130 nm range. Furthermore, the synthesized silver nanoparticles were tested as antimicrobial agents against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa, well-known microorganisms that can produce ulceration phases and severe health consequences. After a comprehensive examination, it was found that the silver nanoparticles have significant antibacterial effectiveness, particularly against S. aureus, a primary bacterium responsible for causing different ailments. The remarkable antibacterial efficacy of the silver nanoparticles synthesized in an environment-friendly manner underscores its potential applications in combating the evolution of antibiotic-resistant strains.

Physico-mechanical Properties of Nano Bio-films For Application in Food Packaging

Petroleum-based packaging has long dominated the packaging industry, raising environmental concerns. As a result, the packaging industry has started using nano bio-plastics. Incorporating nanoparticles, nano bio-plastic packaging helps in prolonging product shelf life. Additionally, packaging manufactured of nano bio-plastic is made of biodegradable polymers. Nano bio-films made from polylactic acid (PLA) and nanoclay were produced using a solvent casting process. 1.0%, 3.0% and 5.0% (wt.) of nanoclay were added to the PLA solution. The mechanical, chemical, morphological and transparency properties of nano bio-films were investigated. To improve their suitability for food packaging applications, tensile test, Fourier-transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM) and UV-barrier test were performed. With tensile strength (TS) of 30.36 MPa and elongation at break (EAB) of 7.05%, respectively, nano bio-films with 3.0 wt. % nanoclay demonstrated higher mechanical properties than pure PLA film with about 35% of increment. In aspects of FTIR analysis, no significant differences were found with both nano bio-films and pure PLA film. The SEM morphology shows that adding nanoclay at 3.0 wt. % improves the adhesion between the PLA matrix and the nanoclay. The addition of nanoclay had a minimal impact on the PLA film's transparency, and it was interesting to see that nanoclay concentration of 1.0 wt. % and 3.0 wt. % had roughly the same light transmission values of 84.86% and 83.95%, respectively. According to the findings of this study, the PLA nano bio-film with 3.0 wt% nanoclay exhibits the optimum physico-mechanical properties.

Efficacy of Sodium Fluoride and Fluoridated Calcium Phosphate in Mitigating Dental Erosion on Human Enamel: An In Vitro Analysis.

With increasing prevalence of dental erosion, this study explores the protective role of traditional fluoride-based products and newer formulations on eroded enamel. To assess the protective effectiveness of casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) and sodium fluoride (NaF) on human enamel against erosion using surface microhardness (SMH) and Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Ten extracted human third molars were sectioned to obtain 40 enamel sections and randomly assigned into four groups (n = 10) and treated as follows: G1 (Sound Enamel), G2 (Erosive Challenge), G3 (CPP-ACPF + Erosive Challenge), and G4 (NaF + Erosive Challenge). All samples were subjected to Vicker's SMH analysis, while changes in surface morphology and elemental composition were validated in few representative samples using FTIR and SEM, respectively. Paired samples test, Kruskal-Wallis test, and Tukey HSD test were performed using SPSS software version 23 setting P value < 0.05 as statistically significant. The mean SMH1 values for the experimental groups G3 and G4 were significantly higher (426.58VHN and 455.83VHN) when compared to G1 (P = 0.000) and G2 (P = 0.000). In SEM analysis, G2 showed eroded honeycomb appearance compared to the smooth homogenous surface of G1, while both G3 and G4 showed deposition of some precipitates. FTIR analysis revealed that in G3 and G4, a characteristic peak of phosphate vibrations between 528 and 823 cm-1 and carbonate bands at 845-932 cm-1 was observed. Both CPP-ACPF and NaF demonstrated a protective effect on enamel against erosive challenge by an orange juice-based beverage.