Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy Research Articles

Combining microscale ATR-FTIR and chemometrics to interpret degradation characteristics of earlywood, latewood, and compression wood in waterlogged archaeological pine wood

AbstractInterpreting the degradation characteristics of waterlogged archaeological wood (WAW) is crucial for the conservation of wooden cultural heritage. Generally, multidisciplinary diagnostic methods, including physical, micromorphological, and chemical approaches, are employed to evaluate the preservation state of WAW. However, primarily focused on the sample level, this methodology limits the understanding of the variability in degradation from a detailed perspective. In this paper, we adopted the in-situ microscale attenuated total reflectance Fourier transform infrared (ATR-FTIR) method to investigate the degradation variability in waterlogged archaeological Masson pine (Pinus massoniana) wood excavated from the ancient Chinese shipwreck Nanhai No. 1. Specifically, spectra of earlywood (EW), latewood (LW), and compression wood (CW) were extracted and combined with chemometrics to achieve rapid classification of their degradation levels. The micromorphological features of wood cell walls in conjunction with the ratios of lignin (A1509) and carbohydrate (A1370) peak areas were used to estimate the degradation levels. Unlike recent wood, moderate degradation in CW and severe degradation in EW and LW were classified in archaeological samples. The degradation levels were effectively determined through principal component analysis (PCA) and sparse partial least squares discriminant analysis (sPLSDA). The results suggest that chemometric analysis is a promising method to discern the variable degradation levels of archaeological wood at the tissue level. The methodologies developed in this study provide detailed insights into the degradation characteristics in WAW and improve the accuracy of evaluating the preservation state.

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.

Levels and Classification of Microplastics and Their Impact on the Wellbeing of Selected Commercially Important Fish Species in Kisumu Bay, Lake Victoria.

Microplastics (MPs) are emerging pollutants of concern in aquatic ecosystems. Fish ingest MPs accidentally during normal feeding because they resemble prey or by ingesting prey that previously consumed them. Despite severe plastic pollution in Africa, some countries, including Kenya have implemented laws to curb this pollution menace. MPs have scantly been studied in African freshwaters. This study provides empirical data and describes the levels of MPs in four commercially important fish species in Lake Victoria. A total of 95 fish samples were collected from four sampling sites (inshore-offshore waters) between March and May 2022. Microscopy and Attenuated Total Reflectance Fourier Transformed Infrared (ATR-FTIR) spectroscopy methods were used to identify MPs. In this study, 62 out of 95 (65.26%) of the gastrointestinal tracts of the sampled fish contained MPs. The four species showed different proportions of detected MPs among the sampled individuals: 75.00% (Clarias gariepinus), 75.00% (Synodontis victoriae), 71.43% (Lates niloticus), and 59.26% (Oreochromis niloticus). Polystyrene (PS) and poly (perfluorobutadiene) were the main plastic polymers in the fish samples. The condition factors estimated for O. niloticus, S. victoriae, and L. niloticus were > 1 and < 1 for C. gariepinus, respectively. Positive correlations were observed between microplastic numbers and fish length and microplastic numbers and fish weight. However, the low R2 values obtained implied no strong relationship exists between these parameters. These findings provide evidence of microplastic contamination in fish in Kisumu Bay.

Microplastic pollution unveiled: the consequences of small unregulated dumping in villages, spanning from soil to water.

Microplastic contamination in soil ecosystems is a major environmental concern in the world. The current study aims to explore the extent of microplastic pollution in unregulated village dumpsites in India, focusing on the movement of these pollutants from soil to aquatic environments. Soil samples from eight distinct sites (A to H) in six villages were analyzed for various properties, including pH, bulk density, porosity, water retention capacity, hydraulic conductivity, and particle size distribution. The attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR) method was used to identify prevalent plastic types. The research classifies microplastics by their shape and color, identifying a wide range of particles such as sheets, fibers, foams, fragments, and films. The study also examines the presence and concentration of microplastics in both soil and sediment samples. It was found that PE and PP microplastics are significantly present across different size fractions. Sample A contains a variety of items in the 1-5mm size range, mainly PE, while the 0.3-1mm fraction is largely PP. Samples B to H are mostly composed of PE microplastics in different forms. Sample F is unique with a mix of PE, EPS, and a higher amount of red and blue foam particles in the 0.3-1mm fraction. Microplastics were quantified using stereomicroscopy, revealing concentrations between 80 and 840 numbers per kilogram in soil and 20 to 60 numbers per kilogram in sediments. The findings emphasize the widespread nature of microplastic pollution across ecosystems and the importance of developing effective strategies for monitoring and mitigating their impact on environmental health and human well-being.

A comparative analysis of PLA and PCL microparticles for hydrophilic and hydrophobic drugs.

This study aims to investigate Polylactic Acid (PLA) and Polycaprolactone (PCL) polymers for microencapsulation of hydrophilic and hydrophobic anti-glaucoma drugs using an emulsion-based solvent evaporation technique. Microparticle size was analysed using optical microscopy, while drug-polymer interactions through Dynamic-Light-Scattering (DLS) and Fourier-Transform-Infra-red/Attenuated-Total-Reflection spectroscopy (FTIR/ATR). In vitro, drug release studies were performed to investigate drug encapsulation and release profiles. Spherical microparticles, with particle size 94 ± 6.9 μm for PCL-based and 100 ± 3.74 μm for PLA-based formulation, were obtained. Drug release studies showed 100% release over about 32 days, with encapsulation efficiency (%EE) and drug loading (%w/w) reaching up to 95 and 2.84% for PLA-based and 97 and 2.91% for PCL-based microparticles, respectively. DLS studies reveal an increase in hydrodynamic radius (RH), which correlates to enhanced drug encapsulation. So, the nature of the drug and polymer significantly impacts drug encapsulation and release, with drug-polymer interactions playing a crucial role alongside experimental parameters.

Plasma enhanced chemical vapor deposition (PECVD) of SiOx thin films on Portuguese limestone: An experimental study

Plasma Enhanced Chemical Vapor Deposition (PECVD) of SiOx thin films has been applied to the stone surface under laboratory conditions in order to assess its feasibility as an alternative method for stone protection. SiOx thin layers were deposited on oolitic limestone lithologies known to have been used for the construction and restoration of the Batalha Monastery in Portugal surface by PECVD from tetraethoxysilane (TEOS) as the reaction precursor, in capacitively coupled parallel-plate reactor. The thickness, morphologies and chemical properties of the deposited film were characterized by attenuated total reflectance -Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy (SEM+EDS). Laboratory simulated decay and natural aging tests were implemented to evaluate the protective effect of the deposited micron-size SiOx thin films. Results suggested that, due to the good barrier effect, SiOx films were able to isolate the stones from aggressive acidic solution, thus reducing possible dissolution-related damage. Natural aging tests proved that SiOx thin films were also able to inhibit to a high extent bio-colonization while, at the same time reducing soiling of the stone appearance. Durability and wetting property of this SiOx thin film were preliminarily assessed. This research tested, for the first time, the feasibility of applying micron-size SiOx film quickly and directly via cold plasma deposition and its versatile protection performance on carbonate stone.

Physicochemical characterization and deterioration condition evaluation of three primary documents of Costa Rica's independence process

This research reports the results of the physicochemical characterization and deterioration condition evaluation of three nineteenth-century manuscripts, which are essential components of the Costa Rican documentary heritage. The documents were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray fluorescence (XRF), and multispectral photography. The documents' condition was thoroughly evaluated, and the results were transformed into an index to correlate their deterioration state with the document's composition; this was achieved by using correlation plots and heatmaps. The study revealed that the Independence Act of Costa Rica was the most deteriorated document among the three manuscripts from the year 1821. This was attributed to its acidic pH level, high zinc content, and greater exposure to light compared to the other two documents.

Innovative label-free lymphoma diagnosis using infrared spectroscopy and machine learning on tissue sections

The diagnosis of lymphomas is challenging due to their diverse histological presentations and clinical manifestations. There is a need for inexpensive tools that require minimal expertise and are accessible for routine laboratories. Contrastingly, current conventional diagnostic methods are often found only in specialized environments. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy offers a nondestructive and user-friendly approach in the analysis of a wide range of samples. In this paper, we determined whether the technique coupled with machine learning can detect and differentiate lymphoma within lymphoid tissue samples. Tissue sections from 295 individuals diagnosed with lymphoma and 389 individuals without the disease were analyzed using ATR-FTIR spectroscopy. The resulting spectral dataset was split using a 70:30 train-test split. Partial least Squares Discriminant Analysis (PLS-DA) models were trained to distinguish non-malignant lymphoid tissue from lymphoma samples and to differentiate between subtypes. On the training set (n = 478), significant spectral differences were mainly identified in the 1800–900 cm–1 region, attributed to fundamental biochemical constituents like proteins, lipids, carbohydrates, and nucleic acids. On the independent test set (n = 206), the trained PLS-DA model achieved a promising AUC of 0.882 (95% CI: 0.881–0.884) in the differentiation between lymphoma and non-malignant lymphoid tissue. In addition, comparative analyses revealed spectral distinctions and notable clustering between the different lymphoma subtypes. This study provides valuable insights into the application of ATR-FTIR spectroscopy and machine learning in the field of lymphoma diagnosis as a non-destructive, rapid and inexpensive tool with the potential to be easily implemented in non-specialized laboratories.

Elucidating Phosphate and Cadmium Cosorption Mechanisms on Mineral Surfaces with Direct Spectroscopic and Modeling Evidence.

The simultaneous sorption of cations and anions at the mineral-water interface can substantially alter their individual sorption characteristics; however, this phenomenon lacks a mechanistic understanding. Our study provides direct spectroscopic and modeling evidence of the molecular cosorption mechanisms of the cadmium ion (Cd2+) and phosphate (P) on goethite and layered manganese (Mn) oxide of birnessite, through in situ attenuated total reflection Fourier-transform infrared (ATR-FTIR), P K-edge X-ray absorption near-edge structure (XANES) spectroscopy, and surface complexation modeling. Phosphate synergistically cosorbed with Cd on goethite predominantly through P-bridged ternary complexes (≡Fe-P-Cd) and electrostatic interactions at wide pH conditions. Likewise, P and Cd exhibited synergistic cosorption on birnessite by forming P-bridged ternary complexes (≡Mn-P-Cd) and weak competitive sorption at the layer edge sites. As pH and Cd loading increased, the surface P species transitioned from a binary complex to a ternary complex and/or Cd3(PO4)2 precipitate for both goethite and birnessite. Compared to that in solution at pH 8, the formation of Cd3(PO4)2 was inhibited by the presence of goethite and birnessite, ascribed to the specific adsorption of P and Cd, more pronounced in birnessite due to the stronger sorption of Cd at its vacant sites. The discovered cosorption mechanisms of P and Cd have important implications for understanding and predicting their mobility and availability in Cd-contaminated settings.

Unveiling the composition of bio-earth from landfill mining and microplastic pollution.

Landfill mining is the prominent solution for the recovery of resources from legacy waste. The bio-earth recovered from landfill mining is being utilized for a variety of applications like application as fertilizer. The presence of microplastic in the recovered bio-earth disrupts its usefulness. This study investigated the composition and microplastic pollution in bio-earth derived from landfill mining at the Bhandewadi landfill, Nagpur, India. Results provided insights into its characterization and presence of microplastic. The average moisture content of the bio-earth was 25.2 ± 1.1% with total organic carbon of 14.3 ± 0.6%. The bio-earth exhibited a C:N ratio of 16.9 ± 5.0, volatile solid content of 24.6 ± 1.0%, and ash content of 75.4 ± 1.0%. Bulk density was 434.3 ± 37.2kg/m3, pH value 6.91 ± 0.28, and electrical conductivity 4.6 ± 0.7 dS/m. Total nitrogen content was 0.9 ± 0.3%, available phosphorus 2.1 ± 0.3g/kg, and potassium and sodium contents of 12.7 ± 0.4g/kg and 3.9 ± 0.3g/kg, respectively. Heavy metals detected included Fe, Zn, Mn, Cu, Pb, Ni, Cr, and Cd. Microplastics in the bio-earth samples were assessed using attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR). The amount of microplastics averaged 100,150 ± 29,286 items per kg (dry basis). Additionally, five specific polymer types were prominent as microplastics. Further research and mitigation strategies are necessary to ensure the safe and sustainable use of bio-earth in agriculture and horticulture.

Analysis of Accelerated Weathering Effect on Polyethylene With Varied Parameters Using a Combination of Analytical Techniques

AbstractPlastics make up a great portion of solid waste that constitutes an emerging threat to the natural environment. Among plastics, polyethylene is the most widely used in the world. In this research, polyethylene materials with different densities designed for packaging applications are the subject of a degradation study. The materials were exposed to simulated solar exposure and were characterized by a combination of analytical techniques to compare both chemical and physical changes, including attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR), water contact angle measurements, Raman spectroscopy, grazing incidence X‐ray Diffraction (GIXRD) and nanoindentation tests. The experimental data were systematically analyzed using statistic methods. It was found that the extent of the increase of polar groups, hydrophilicity, crystallinity, and elastic modulus depends on both the density of polyethylene and the duration of UV aging. These changes result from photooxidation and the subsequent structure reorganization occurring in amorphous chains. The implementation of various analytical techniques and statistical analysis provides a holistic understanding of polyethylene degradation behaviors. The knowledge of increased hydrophilicity/polarity in polyethylene is crucial for understanding the fate of plastics in the environment because such polyethylene changes also facilitate the environmental biodegradation on initially non‐polar polyethylene.

Production and characterization of bacterial cellulose synthesized by Enterobacter chuandaensis strain AEC using Phoenix dactylifera and Musa acuminata.

Bacterial cellulose (BC) is a biopolymer synthesized extracellularly by certain bacteria through the polymerization of glucose monomers. This study aimed to produce BC using Enterobacter chuandaensis with fruit extracts from Phoenix dactylifera (D) and Musa acuminata (M) as carbon sources. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) showed characteristic cellulose vibrations, while X-ray diffraction (XRD) identified distinct peaks at 15.34°, 19.98°, 22.58°, and 34.6°, confirming the cellulose structure. Whole-genome sequencing of E. chuandaensis identified key genes involved in BC production. The BC produced then exhibited a molecular weight of 1,857,804g/mol, with yields of 2.8g/L and 2.5g/L for treatments D and M, respectively. The crystallinity index of the purified BC was 74.1, and 13C NMR analysis confirmed the dominant cellulose Iα crystalline form. The BC showed high biocompatibility in cytotoxicity assays, with cell viability between 92% and 100%, indicating its potential for use in biomedical applications. This investigation represents the first report of BC production by E. chuandaensis, which promises a new avenue for sustainable and efficient BC synthesis using fruit extracts as carbon sources.

Enhanced Ocular Drug Delivery of Dexamethasone Using a Chitosan-Coated Soluplus®-Based Mixed Micellar System

Background: This study introduces a novel dexamethasone (DEX) mixed micellar system (DEX-MM) using Soluplus® and Pluronic F-127 (PF127) to enhance ocular drug delivery. The enhancement of ocular application properties was achieved by creating a chitosan-coated DEX-MM (DEX-CMM), which promotes better adherence to the ocular surface, thereby improving drug absorption. Methods: Using the solvent evaporation method, a formulation was developed with a Soluplus®-to-drug ratio of 1:10, enhanced with 0.25% PF127. After dispersing in water, 1% chitosan (CS) was added. The stability and integrity of DEX within the micelles were verified using attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC). Additionally, in vitro and ex vivo drug release studies were conducted. Results: DEX-CMM (F6) demonstrated a particle size of 151.9 ± 1 nm and a polydispersity index (PDI) of 0.168 ± 0.003, suggesting uniformity and high electrostatic stability with a zeta potential of +35.96 ± 2.13 mV. The non-Fickian drug release mechanism indicated prolonged drug retention. Comparative analyses showed DEX-CMM outperforming a standard DEX suspension in drug release and ocular tissue permeation, with flux measurements significantly higher than the DEX suspension. Conclusion: The study confirmed the efficacy of DEX-CMM in enhancing drug delivery to ocular tissues, evidenced by improved permeability. Safety evaluations using the HET-CAM test demonstrated that DEX-CMM was non-irritant, supporting its potential for effective ocular drug delivery.

Preparation and Characterization of Cellulose/Silk Fibroin Composite Microparticles for Drug-Controlled Release Applications

Microparticles derived from biomaterials are becoming increasingly popular for application in drug delivery systems. In this study, the water-in-oil (W/O) emulsification–diffusion method was used to create cellulose (C), silk fibroin (SF), and C/SF composite microparticles. We then observed the morphology of all obtained microparticles using scanning electron microscopy (SEM), evaluated their functional groups using attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR), and conducted thermogravimetric analysis using a thermogravimetric analyzer (TGA). SEM micrographs indicated that the native SF microparticles have the highest spherical shape with smooth surfaces. With blue dextran, the C microparticle was smaller than the native microparticle, while the drug-loaded SF microparticles were larger than the native microparticle. The morphological surfaces of the C/SF composite microparticles were varied in shape and surface depending on the C/SF ratio used. The spherical shape of the C/SF composite microparticle increased as the SF content increased. Furthermore, the size of the drug-loaded C/SF composite microparticles increased when the SF content gradually increased. The significant functional groups in the C and SF structures were identified based on the ATR-FTIR data, and a suggestion was made regarding the interaction between the functional groups of each polymer. When compared to both native polymers, the C/SF composite microparticles exhibit improved thermal stability. XRD patterns indicated that all prepared particles have crystalline structures and are directly affected by the released profile. The C/SF composite microparticle at a 1:3 ratio had the lowest drug release content, whereas the hydrophilicity of the C microparticle affected the highest drug release content. As a result, one crucial factor affecting the medication released from the microparticle is its structure stability. According to the obtained results, C, SF, and C/SF composite microparticles show promise as delivery systems for drugs with controlled release.

Polymerization kinetics of 3D-printed orthodontic aligners under different UV post-curing conditions

BackgroundThe purpose of the study was to measure the degree of conversion (DC) of direct-printed aligners (DPA) that were post-cured under ambient and nitrogen atmosphere at specific time intervals and investigate the kinetics of polymerization reaction of this material.MethodsA total of 48 aligners were produced in 4 printing series by a 3D printer with TC-85DAC resin (Graphy Inc). From each series of printing, 12 aligners were included. The aligners were divided into two groups according to their post-curing conditions. One group was post-cured under ambient air with the presence of oxygen and the other under a nitrogen atmosphere, both using the same UV post-curing unit recommended by the company. The aligners were post-cured at six different time intervals: 1, 2, 3, 5, 10, and 20 min. Each time interval included 8 aligners, with 2 aligners from each series. The DC of the cured aligners was measured by means of attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) through acquisition of the respective spectra for each UV-curing condition. Statistical analysis was performed to compare the results and differences within each atmosphere post-curing protocol, as well as between the different selected atmosphere conditions. Statistical significance level was set at p-value ≤ 0.05.ResultsPairwise analysis between post-curing protocols showed statistically significant differences only at the first minute of polymerization. Post-curing with nitrogen did not yield statistically significant results across different time intervals. Post-curing in ambient air showed some significant differences on the 1st and 2nd minute of the post-curing process.ConclusionsAlmost complete double bond conversion was observed. Significant differences were observed only during the first minute of polymerization under the nitrogen atmosphere.

Electricallymodified bacterial cellulose tailored with plant based green materials for infected wound healing applications

Effective treatment of infected wounds remains a challenge due to the rise of antibiotic-resistant microorganisms. The development of advanced materials with strong antimicrobial properties is necessary to address this issue. In this study, a unique composite of electrically modified bacterial cellulose (EBC) with allantoin (ABC) and zein was developed by dipping diffusion method. Morphological structural analysis revealed a uniform distribution of zein and aligned fibers, confirming the synthesis of the ABC-Zein composite. The formation of ABC-Zein was further confirmed by attenuated total reflection-Fourier transform infrared (ATR-FTIR), which displayed additional peaks corresponding to EBC, indicating the incorporation of zein into ABC. X-ray diffraction (XRD) analysis of ABC-Zein demonstrated a similar crystalline structure with EBC. The ABC-Zein showed mechanical integrity (tensile strength: 1.15 ± 0.21 MPa), thermal stability (degradation temperature: 290 °C), porous structure (porosity: 40.23 ± 0.21 %), and hydrophilic (water contact angle: 53.3 ± 5.3°) properties. Furthermore, the antimicrobial agent terpinen-4-ol (T4O), derived from tea tree oil, was incorporated into the ABC-Zein composite. Biological studies confirmed the antimicrobial efficacy (Staphylococcus aureus inhibition: 88.5 ± 7.19 %) and biocompatible (cell viability: 84.95 ± 5.6 %, hemolysis: 4.479 ± 0.39 %) nature of the T4O-ABC-Zein composite. The combined effects of the aligned fiber structure, zein protein, and antimicrobial T4O significantly enhanced infected wound healing by day 7, promoting inflammatory response, granular tissue formation, cell proliferation, and angiogenesis. By day 14, T4O-ABC-Zein facilitated complete wound healing, with reepithelization, collagen I deposition, and downregulation of CD 31, Ki67, and α-SMA. Overall, the innovative T4O-ABC-Zein composite, with an aligned fiber structure, improved biocompatibility, and antimicrobial properties, holds significant potential for the treatment of infected wounds.

ATR-FTIR characterisation of daily-use plastics mycodegradation

Synthetic polymers, such as plastics, have permeated all aspects of modern life, and nowadays plastic pollution is a major environmental problem. Mycodegradation of these polymers could represent part of the solution to this problem since it calls on a broad toolbox of enzymes and applies non-enzymatic mechanisms to degrade and deteriorate recalcitrant materials. However, not enough is known about this ability for most of the representatives of the fungal kingdom. Another bottleneck is the harmonisation of technologies to analyse plastic degradation. This work involved the design of a biodegradation experiment, where the potential of four fungi representative of Dikarya and Penicillia (Funalia floccosa, Trametes versicolor, Pycnoporus cinnabarinus and Penicillium oxalicum) were tested on their ability to deteriorate the six most used plastics based on gravimetry and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The following correlation between changes in the band signals and the loss of mass after treatment was determined using polyethylene terephthalate, polypropylene, polyethylene, poly vinyl chloride, high density polyethylene, low density polyethylene and nylon. After treatment, the decrease in absorbance of the characteristic bands of the plastics was taken as an indication of the degradation of the corresponding bonds/functionalities. The four fungi used could transform CH, CH2, CH3, CO, CO, CN, NH and CCl bonds. The best result was obtained using the fungus F. floccosa with 90-day treatments for high density polyethylene (∼ 62.0 %), low density polyethylene (∼ 23.6 %) and nylon (∼ 35.6 %). Therefore, mycodegradation could open up new doors in the fight against plastic pollution.

Iron Age Fur Skin Tanning – a Sustainable Practice?

Tanning is among the most polluting industries in the world. Industrial-produced hides and skins are fully or pre-tanned with highly polluting chromium salts. The purpose of the study was to gain new knowledge about Iron Age tanning methods to clarify whether sustainable tanning methods can be developed based on this. Fur skin capes, uncovered in Jutland bogs, from Baunsø Mose (20-220 AD), Borremose I (365-116 BC), Huldremose I (1-174 AD) and Vindum Mose (386-203 BC) were analysed by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Gas Chromatography-Mass Spectrometry (GC-MS) and morphological assessment of the skin fibres to identify tanning substances and material condition. Analyses were supplemented with source studies of previous visual assessment of the capes and measured shrinkage temperature of leather and skins excavated from bogs. Our results show that only the samples from Baunsø Mose, Borremose I and Huldremose I contain vegetable tannins. Furthermore, Baunsø Mose contains cow fat and Borremose I, Huldremose I and Vindum sheep fat. All contain indications of the presence of aluminum and iron compounds. The samples are decomposed to varying extents. Remnants from conservation were detected on Huldremose I, Baunsø Mose and Vindum Mose.

Nonthermal Atmospheric Plasma Promotes Bonding Between Adhesive Monomers and Zirconia.

To investigate whether nonthermal atmospheric plasma (NTAP) can promote bonding between commonly used adhesive monomers and zirconia. The zirconia surface and monomers (HEMA, BisGMA, TEGDMA, and MDP) were treated with different NTAP approaches (10 w, 30 s), and the surface characteristics and chemical structures between the zirconia surface and monomers were verified by the contact angle, scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR/FT-IR) spectroscopy, and x-ray photoelectron spectroscopy (XPS). Scotchbond Universal adhesive with two different resin cements, RelyX Ultimate and RelyX Unicem 2, was applied, followed by NTAP-aided clinical procedures, and then microtensile bond strength test (μTBS) and failure mode evaluation were tested for preliminary mechanical properties assessment. One-way ANOVA was employed for the statistical analysis. The contact angle analysis, SEM, and ATR-FTIR confirmed that NTAP can promote the polymerization of BisGMA, TEGDMA, and MDP on the zirconia surface, while XPS confirmed that NTAP can induce a chemical reaction between MDP and zirconia. Nonthermal atmospheric plasma can increase the affinity between selected monomers and zirconia and promote the chemical bonding strength between phosphate monomers and zirconia; besides, it can enhance the bonding strength of two different adhesive systems. The mechanism of how NTAP improved common adhesive monomers interacting with zirconia surfaces was revealed in this study. NTAP, as a relatively high energy-boosting method, could not only improve the surface affinity of zirconia and chemical bonding in-between monomers and zirconia but also enhance the polymerization of different monomers onto zirconia, resulting in improved bonding properties. Thus, further exploration of versatile bonding materials and/or onto different dental substrates could take this into account.

Decoding Hydrogen Desorption Kinetics in Porous Silicon: An Electrical Circuit Modeling Approach.

Solid-state hydrogen storage outperforms conventional storage methods in terms of safety and on-board applications. Porous Si (PS) is the optimized Si nanostructure with ample surface area (∼400 m2 g-1) and maximum dangling sites for hydrogenation. Though solid-state hydrogen storage in Si nanostructures, especially in porous Si, is extensively studied, the thermal desorption of hydrogen is rarely reported. This work investigates and analyzes the thermal desorption of a hydrogen-terminated PS surface using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) to optimize the temperature for efficient desorption, as FTIR is sensitive to identifying the presence of Si hydride species (SiHx). The relative peak intensities in the spectra estimate the relative hydrogen retention (γ) for the analysis of the desorption kinetics. The desorption curves are divided into two zones on the time scale: the excitation zone and the recombination zone, separated by the recombination threshold point. The initially absorbed energy breaks the Si-Hx bonds in the excitation zone to reach the recombination threshold for H2 formation. The recombination zone is further divided into two subzones: the avalanche subzone (a sudden decrease in γ indicating molecular desorption) and the saturation subzone (almost constant γ with minimal desorption). The time constant from the first-order reaction kinetic fitting of the desorption curves explores the time-temperature correlation and the barrier energy estimation for the excitation and recombination zones. The analysis identifies the critical operating point for desorption as 100 °C and 4 min, with the optimized temperature of 250 °C. This article applies an analogous electrical circuit to compare the thermal hydrogen desorption and capacitor discharge circuit for analytical convenience.