Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy Research Articles

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.

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.

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.

Impact of UV Light Exposure During Printing on Thermomechanical Properties of 3D-Printed Polyurethane-Based Orthodontic Aligners

Aim: Polyurethane-based aligners, created through photoinitiated free-radical polymerization, have been the subject of numerous studies focusing solely on their mechanical properties. In contrast, we investigate their thermomechanical properties, which are crucial for their efficacy. This paper aims to investigate the effects of different UV light exposure durations on the complex modulus of elasticity, tan delta, glass transition temperature, and the degree of conversion (DC). Methods: Aligners were printed using Tera Harz TC-85 and NextDent Ortho Flex resin with specific exposure times (2, 2.4, 3, 4, and 4.5 s for Tera Harz; 5, 6, 7, and 8 s for NextDent) and processed per manufacturer guidelines. The degree of conversion was analyzed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, while Dynamic Mechanical Analysis (DMA) characterized the mechanical properties (complex modulus and tan delta) and the glass transition. Results: Tera Harz TC-85 showed a higher degree of conversion (90.29–94.54%), suggesting fewer residual monomers, which is potentially healthier for patients. However, its lower glass transition temperature (35.60–38.74 °C) might cause it to become rubbery in the mouth. NextDent Orto Flex, with a higher storage modulus (641.85–794.55 MPa) and Tg (49.36–50.98 °C), offers greater rigidity and stability at higher temperatures (greater than temperature in the oral cavity), ideal for orthodontic forces, though its lower degree of conversion raises health concerns. Conclusions: Tera Harz TC 85 generally achieves higher DC and more stable polymerization across different UV exposure times than NextDent Orto Flex. Optimal polymerization times significantly impact both the mechanical and thermal properties of these dental resins, with NextDent showing optimal properties at 7 s and Tera Harz benefiting from both very short and extended exposure times.

Accelerated In Vitro Oxidative Degradation Testing of Ultra-High Molecular Weight Polyethylene (UHMWPE).

Nonabsorbable polymers used in biomedical applications are assumed to be permanently stable based on short-term testing, but some may be susceptible to oxidative degradation over several years of implantation. Traditional in vitro oxidative degradation screenings employ hydrogen peroxide (H2O2) solutions. However, the inherent instability of H2O2 can compromise the consistency of oxidative conditions, especially over extended periods and at elevated temperatures used for accelerated testing. In this study, an automated reactive accelerated aging (aRAA) system, which integrates an electrochemical detection method and a feedback loop, was utilized to ensure precise control of H2O2 concentrations during polymer oxidative degradation testing. The reproducibility of the aRAA system was evaluated by comparing four identical setups. Its efficacy as an oxidation challenge was demonstrated on (i) medical-grade vitamin E (VE) blended ultra-high molecular weight polyethylene (UHMWPE) and (ii) highly crosslinked (HXL) UHMWPE as model materials. The aRAA-aged VE-UHMWPE and HXL-UHMWPE samples were also compared against samples aged via an existing accelerated aging standard, ASTM F2003-02(2022). Samples were analyzed using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to calculate their oxidation index per ASTM F2102-17. We observed that the aRAA system was more effective in oxidizing VE-UHMWPE and HXL-UHMWPE than the traditional ASTM F2003-02(2022) method. By providing a standardized and reliable approach to assess polymer oxidative degradation, the aRAA system could enhance the accuracy of long-term stability predictions for nonresorbable polymers in medical devices.

Study on Quality and Starch Characteristics of Powdery and Crispy Lotus Roots.

Nine varieties of lotus root (Suining, Xinhe, Zaohua, Zhonghua, L0014, L0013, Cuiyu, L0011, and Zhenzhu) were selected as the research materials to compare their differences in physical, chemical, and starch characteristics before and after boiling, frying, and microwaving. The results showed that Zhenzhu, Xinhe, L0013, Cuiyu, and Zhonghua belong to the crispy lotus root type, while L0011, L0014, Zaohua, and Suining belong to the powdery lotus root type. Furthermore, the nine varieties were characterized for their starch by optical micrograph (OM), polarized micrograph (PM), scanning electron micrograph (SEM), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), carbon-13 cross-polarization/magic angle spinning nuclear magnetic resonance (13C CP/MAS NMR), and differential scanning calorimetry (DSC). The starch granule of powdery lotus root appeared to be larger than that of crispy lotus, and ATR-FTIR studies revealed that the outer layer of starch granules from nine different varieties of lotus root had a highly organized structure. Moreover, XRD and 13C CP/MAS NMR analyses revealed that starch from eight lotus varieties (Suining, Xinhe, Zaohua, Zhonghua, L0014, L0013, Cuiyu, L0011) belong to the A-crystal type, while starch from Zhenzhu belongs to the CA-crystal type. The starch from powdery lotus root exhibited higher crystallinity, as well as increased gelatinization temperature and enthalpy, indicating that its crystal structure was relatively superior compared to that of crispy lotus starch. The short-range order degree, crystallinity, gelatinization temperature, and heat enthalpy of lotus starch decreased after boiling and frying but increased to varying extents after microwaving. Additionally, the heat resistance and stability of starch particles from crispy lotus root were improved after microwave treatment.

Rapid Identification of Medicinal Polygonatum Species and Predictive of Polysaccharides Using ATR-FTIR Spectroscopy Combined With Multivariate Analysis.

Medicinal Polygonatum species is a widely used traditional Chinese medicine with high nutritional value, known for its anti-fatigue properties, enhancement of immunity, delays aging, improves sleep, and other health benefits. However, the efficacy of different species varies, making the quality control of medicinal Polygonatum species increasingly important. Polysaccharides are important in medicinal Polygonatum species because of their potential functional properties, such as antioxidation, hypoglycemia, protection of intestinal health, and minimal toxicological effects on human health, as well as high polysaccharide levels. This study developed a qualitative medicinal Polygonatum species model and a polysaccharides predictive model based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) combined with a multivariate analysis approach. ATR-FTIR spectral information of 334 medicinal Polygonatum species samples was collected and the spectral information of different modes was analyzed. The ATR-FTIR spectral differences of three medicinal Polygonatum species were studied by multivariate analysis combined with four spectral preprocessing and three variable selection methods. For the prediction of polysaccharides in Polygonatum kingianum Collett & Hemsl. (PK), we initially determined the actual content of 110 PK polysaccharide samples using the anthrone-sulfuric acid method, then established partial least squares regression (PLSR) and kernel PLSR models in conjunction with attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. In the visualization analysis, the orthogonal partial least squares-discriminant analysis (OPLS-DA) model based on second-order derivative (SD) preprocessing was most suitable for medicinal Polygonatum species species binary classification, spectral differences between Polygonatum cyrtonema Hua (PC) and other species are evident; in the hard modeling, SD preprocessing improves the accuracy of non-deep learning models for the classification of three medicinal Polygonatum species. In contrast, residual neural network (ResNet) models were the best choice for species identification without preprocessing and variable selection. In addition, the partial least squares regression (PLSR) model and Kernel-PLSR model can quickly predict PK polysaccharides content, among them, the Kernel-PLSR model with SD pretreatment has the best prediction performance, residual prediction deviation (RPD) = 7.2870, Rp = 0.9905. In this study, we employed ATR-FTIR spectroscopy and various treatments to discern different medicinal Polygonatum species. We also evaluated the effects of preprocessing methods and variable selection on the prediction of PK polysaccharides by PLSR and Kernel-PLSR models. Among them, the ResNet model can achieve 100% correct classification of medicinal Polygonatum species without complex spectral preprocessing. Furthermore, the Kernel-PLSR model based on SD-ATR-FTIR spectra had the best performance in polysaccharides prediction. In summary, by integrating ATR-FTIR spectroscopy with multivariate analysis, this research accomplished the classification of medicinal Polygonatum species and the prediction of polysaccharides. The methodology offers the benefits of speed, environmental sustainability, and precision, highlighting its significant potential for practical applications. In future research, on the one hand, it can be further investigated using a portable infrared spectrometer, and on the other hand, infrared spectroscopy can also be applied to the prediction of other chemical components of medicinal Polygonatum species.

Combining Mesoporous Bioactive Glass Nanoparticles (MBGNs) with Essential Oils to Tackle Bacterial Infection and Oxidative Stress for Bone Regeneration Applications.

Bacterial infectious diseases remain one of the significant challenges in the field of bone regeneration applications. Despite the development of new antibiotics, their improper administration has led to the development of multiresistant bacterial strains. In this study, we proposed a novel approach to tackle this problem by loading clove oil (CLV), a natural antibacterial compound, into amino-functionalized mesoporous bioactive glass nanoparticles (MBGNs). The scanning electron microscopy images (SEM) revealed that amino-functionalization and CLV loading did not affect the shape and size of the MBGNs. The successful grafting of the amino groups on the MBGNs' surface and the presence of CLV in the material were confirmed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and zeta potential measurements. The increased CLV concentration led to a higher loading capacity, encapsulation efficiency, and antioxidant activity. The in vitro CLV release profile exhibited an initial burst release, followed by a controlled release over 14 days. The loading of CLV into MBGNs led to a stronger antibacterial effect against E. coli and S. aureus, while MG-63 osteoblast-like cell viability was enhanced with no morphological changes compared to the control group. In conclusion, the CLV-MBGNs nanocarriers showed promising properties in vitro as novel drug delivery systems, exploiting essential oils for treating bone infections and oxidative stress.

Preparation, characterization, and in vitro cytogenotoxic evaluation of a novel dimenhydrinate-β-cyclodextrin inclusion complex.

Dimenhydrinate (DMH), used to alleviate motion sickness symptoms such as nausea, vomiting, dizziness, and vertigo, encounters limitations in oral pharmaceutical formulations due to its poor water solubility and bitter taste. Our research hypothesized that inclusion complexation with β-cyclodextrin (β-CD) might address these drawbacks while ensuring that the newly formed complexes exhibit no cytotoxic or genotoxic effects on peripheral blood mononuclear cells (PBMCs). Inclusion complexes were prepared using the kneading method and the solvent evaporation method. The phase solubility analysis, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), and differential scanning calorimetry (DSC) were conducted to evaluate the complexation efficacy and stability constant of the new binary systems. The results demonstrated that both methods provided complete and efficient complexation. Cytogenotoxic analysis, including the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, alkaline comet assay, and cytokinesis-block micronucleus cytome (CBMN-cyt) assay, was conducted to assess the cytogenotoxic potential of DMH-β-CD inclusion complexes, a topic previously unexamined. No cytotoxic or genotoxic effects were observed within the concentration range of 36.36 to 109.09 ng/mL. Cell viability of treated PBMCs exceeded 85% for all tested concentrations. No significant increases in DNA strand breaks were observed at any dose, and tail intensity of all complexes remained lower or up to 2.2% higher than the negative control. Parameters indicating genotoxic effects, as well as cytotoxic and cytostatic potential in the CBMN-cyt assay, did not significantly differ from untreated controls. These results suggest that inclusion complexation with β-CD might be a safe and promising solution to overcome the limitations of poor solubility and unpleasant taste of DMH, potentially providing opportunities for new and improved oral pharmaceutical dosage forms.

Covalent Lysozyme Immobilization on Enzymatic Cellulose Nanocrystals.

Nanostructured materials represent promising substrates for biocatalyst immobilization and activation. Cellulose nanocrystals (CNCs), accessible from waste and/or renewable sources, are sustainable and biodegradable, show high specific surface area for anchoring a high number of enzymatic units, and high thermal and mechanical stability. In this work, we present a holistic enzyme-based approach to functional antibacterial materials by bioconjugation between the lysozyme from chicken egg white and enzymatic cellulose nanocrystals. The neutral CNCs were prepared by endoglucanase hydrolysis from Avicel. We explore the covalent immobilization of lysozyme on enzymatic CNCs and on their TEMPO oxidized derivatives (TO-CNCs), comparing immobilization yields, material properties, and enzymatic activities. The materials were characterized by X-ray diffractometry (XRD), attenuated total reflectance Fourier Transform infrared spectroscopy (ATR-FTIR), bicinchoninic acid (BCA) assay, field-emission scanning electron microscopy (FE-SEM) and dynamic light scattering (DLS). We demonstrate the higher overall efficiency of the immobilization process carried out on TO-CNCs, based on the success of covalent bonding and on the stability of the isolated bioconjugates.

Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis of human nails: Implications for age determination in forensics.

A person's age estimation from biological evidence is a crucial aspect of forensic investigations, aiding in victim identification and criminal profiling. In this study, we present a novel approach of utilizing Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) spectroscopy to predict the age of donors based on nail samples. A diverse dataset comprising nails from donors spanning different age groups was analyzed using ATR FT-IR, with subsequent multivariate analysis techniques used for age prediction. The developed partial least squares regression (PLS-R) model demonstrated promising accuracy in age estimation, with a root mean square error of prediction (RMSEP) equal to 11.1 during external validation. Additionally, a partial least squares discriminant analysis (PLS-DA) classification model achieved high accuracy of 88% in classifying donors into younger and older age groups during external validation. This proof-of-concept study highlights the potential of ATR FT-IR spectroscopy as a non-destructive and efficient tool for age estimation in forensic investigations, offering a new approach to forensic analysis with practical implications.

Fabrication and Optimization of Parameters of High-Performance Polyamide Thin Film Composite Membranes for Desalination

Abstract Herein, we report the synthesis of polyamide thin film composite (PA-TFC) membranes through interfacial polymerization (IP) using an aqueous solution of diaminodiphenylmethane (DDM) and terephthaloyl chloride (TPC) in n-hexane, onto polysulfone (PSF) surface. The synthesized membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM) and contact angle measurement. To optimize the conditions for achieving a better membrane function, desalination (%) and permeate flow rate (L/m2.h.bar) were evaluated as a function of synthesis conditions. The membrane efficiency for salt rejection was evaluated against NaCl using a bench-top cross-flow filtration assembly where the membrane showed up to 73.13% salt rejections of NaCl. While, the salt rejection of Na2SO4 and MgSO4 were showed up to 84.92% and 82.94%. The promising synthesized membranes exhibited a permeate flux of 41.7 L/m2.hr.bar. The contact angle analysis revealed that the synthesized PA-TFC membranes are hydrophilic as the value of contact angle measured as 109°-100°. The synthesized membrane offered facile and effective access for the synthesis of high-performance PA-TFC membranes.

Infrared spectroscopy as a new approach for early fabry disease screening: a pilot study

BackgroundFabry disease (FD) is a rare X-linked lysosomal storage disorder marked by alpha-galactosidase-A (α-Gal A) deficiency, caused by pathogenic mutations in the GLA gene, resulting in the accumulation of glycosphingolipids within lysosomes. The current screening test relies on measuring α-Gal A activity. However, this approach is limited to males. Infrared (IR) spectroscopy is a technique that can generate fingerprint spectra of a biofluid’s molecular composition and has been successfully applied to screen numerous diseases. Herein, we investigate the discriminating vibration profile of plasma chemical bonds in patients with FD using attenuated total reflection Fourier-transform IR (ATR-FTIR) spectroscopy.ResultsThe Fabry disease group (n = 47) and the healthy control group (n = 52) recruited were age-matched (39.2 ± 16.9 and 36.7 ± 10.9 years, respectively), and females were predominant in both groups (59.6% and 65.4%, respectively). All patients had the classic phenotype (100%), and no late-onset phenotype was detected. A generated partial least squares discriminant analysis (PLS-DA) classification model, independent of gender, allowed differentiation of samples from FD vs. control groups, reaching 100% sensitivity, specificity and accuracy.ConclusionATR-FTIR spectroscopy harnessed to pattern recognition algorithms can distinguish between FD patients and healthy control participants, offering the potential of a fast and inexpensive screening test.

Structural and Spectroscopic Characterization of Supported Sarcoplasmic Reticulum Membranes on Solid Substrates.

Sarcoplasmic reticulum (SR) membranes from rabbit muscle were deposited on silicon substrates and characterized by the combination of spectral ellipsometry (SE), high energy specular X-ray reflectivity (XRR), specular neutron reflectivity (NR), and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Following the optimization of the preparative conditions by SE, the detailed structures in the direction perpendicular to the membrane were probed by XRR. ATR-FTIR data showed strong signals from amide I and amide II bands of the native SR membranes containing a large amount of Ca2+-ATPase, which could not be achieved by the reconstitution in artificial lipid membranes. The treatment with protease led to a significant decrease in the amide peaks, and the XRR data confirmed the modulation of the membrane structures. The obtained data show the potential of the in situ combination of reflectivity and vibrational spectroscopy of native supported membranes in order to unravel both structure and dynamics of complex biological membranes.

Ancient and modern bone diagnosis: Towards a better understanding of chemical and structural feature alterations

Chemical and structural alterations hold great importance in the field of diagenesis. Attenuated Total Reflectance − Fourier Transform Infrared Spectroscopy (ATR-FTIR) is a valuable method for examining bio-apatite composition changes. Infrared spectroscopy (IR) and X-ray diffraction (XRD) were employed to analyze both modern and archaeological bone specimens. Organic and mineral component changes in modern and ancient samples were investigated. Ancient bone samples were collected from two archaeological sites in Jordan, dating back to the Iron and Byzantine ages. IR results indicated that collagen cross-links and mineral maturity are higher in modern bones compared to ancient bones. Additionally, the crystallinity index is higher in modern bones than in archaeological bones, while the carbonate to phosphate ratio (C/P) is lower in modern bones than in ancient ones. Curve fitting was applied to reveal the carbonate substitution inside the hydroxyapatite lattice within the IR region from 850 to 890 cm−1. A2-type carbonates (identified as υ2 of CO32−) denote hydroxyl site substitution, and B-type carbonates represent a substitution to the phosphate site. The full width at half maximum (FWHM) of the peak at 604 cm−1 from IR spectra reveals that crystallinity is higher in modern bones, as confirmed by the FWHM of the (002)-apatite pattern in XRD. Statistical analysis was conducted to validate these findings, ensuring the robustness of the results. Finally, the results obtained in this investigation align with previous literature reports regarding ATR-FTIR ratios. This suggests that modern bones have better crystallinity compared to ancient bones. Furthermore, the ATR-FTIR ratios indicate that the hydroxyl and phosphate sites of modern bones undergo more substitution than older bones. The findings of this study not only enhance our understanding of the diagnostic processes in archaeological bone specimens but also have broader implications for fields such as archaeology, anthropology, and forensics, where the analysis of bone composition and structural changes can provide valuable insights into the history and characteristics of ancient remains.