Reflectance Fourier Transform Infrared Spectroscopy Research Articles

H.O.S.T.: Hemoglobin microbubble-based Oxidative stress Sensing Technology

In this work, we discuss the development of H.O.S.T., a novel hemoglobin microbubble-based electrochemical biosensor for label-free detection of Hydrogen peroxide (H2O2) towards oxidative stress and cancer diagnostic applications. The novelty of the constructed sensor lies in the use of a sonochemically prepared hemoglobin microbubble capture probe, which allowed for an extended dynamic range, lower detection limit, and enhanced resolution compared to the native hemoglobin based H2O2 biosensors. The size of the prepared particles Hemoglobin microbubbles was characterized using Coulter Counter analysis and was found to be 4.4 microns, and the morphology of these spherical microbubbles was shown using Brightfield microscopy. The binding chemistry of the sensor stack elements of HbMbs’ and P.A.N.H.S. crosslinker was characterized using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy and UV–Vis Spectroscopy. The electrochemical biosensor calibration (R2 > 0.95) was done using Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, and Square Wave Voltammetry. The electrochemical biosensor calibration (R2 > 0.95) was done using Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, and Square Wave Voltammetry. The specificity of the sensor for H2O2 was analyzed using cross-reactivity studies using ascorbic acid and glucose as interferents (p < 0.0001 for the highest non-specific dose versus the lowest specific dose). The developed sensor showed good agreement in performance with a commercially available kit for H2O2 detection using Bland Altman Analysis (mean bias = 0.37 for E.I.S. and − 24.26 for CV). The diagnostic potential of the biosensor was further tested in cancerous (N.G.P.) and non-cancerous (H.E.K.) cell lysate for H2O2 detection (p = 0.0064 for E.I.S. and p = 0.0062 for CV). The Michaelis Menten constant calculated from the linear portion of the sensor was found to be {K}_{m}^{app} of 19.44 µM indicating that our biosensor has a higher affinity to Hydrogen peroxide than other available enzymatic sensors, it is attributed to the unique design of the hemoglobin polymers in microbubble.

CO2 Hydrogenation to Gasoline and Aromatics: Mechanistic and Predictive Insights from DFT, DRIFTS and Machine Learning.

The emission of CO2 from fossil fuels is the largest driver of global climate change. To realize the target of a carbon-neutrality by 2050, CO2 capture and utilization is crucial. The efficient conversion of CO2 to C5+ gasoline and aromatics remains elusive mainly due to CO2 thermodynamic stability and the high energy barrier of the C-C coupling step. Herein, advances in mechanistic understanding via Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), density functional theory (DFT), and microkinetic modeling are discussed. It further emphasizes the power of machine learning (ML) to accelerate the search for optimal catalysts. A significant effort has been invested into this field of research with volumes of experimental and characterization data, this study discusses how they can be used as input features for machine learning prediction in a bid to better understand catalytic properties capable of accelerating breakthroughs in the process.

Oxidative effects of gaseous oxygen and ozone on Australian subbituminous and bituminous coals and the implications for coal seam permeability enhancement

The use of gaseous ozone as a means for enhancing coal seam permeability has been investigated, including the effect on subbituminous and bituminous coal from the Surat and Bowen Basins, Australia, respectively. To elucidate the oxidative mechanism, the chemical properties of the Surat coal before and after oxidation was examined using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS). Additionally, gas adsorption techniques and optical microscopy were used to assess physical changes arising from the ozone treatment. Although both the oxygen and ozone treatments (two days duration) increased the oxygen content in the molecular structure of the coal, the ozone introduced significantly more, specifically with the generation of aliphatic ester CO groups and aromatic carbonyl/carboxyl CO groups. In terms of the physical structure of the coal, the micropore volume was slightly reduced by the oxygen treatment but almost eliminated by the ozone treatment. Furthermore, oxygen treatment showed little impact on the coal mass loss while ozone oxidation caused a 0.7% loss in coal weight. Additional tests on a Bowen Basin coal showed an increase in the aperture (4.37%) of a cleat after ozone treatment. These results demonstrate the potential of ozone for coal seam permeability enhancement by merging micropores and increasing cleat apertures whilst maintaining the structural integrity of the coal.

Screening of Microplastics in Aquaculture Systems (Fish, Mussel, and Water Samples) by FTIR, Scanning Electron Microscopy–Energy Dispersive Spectroscopy and Micro-Raman Spectroscopies

In the last decade, plastic waste has become one of the main threats to marine ecosystems and their biodiversity due to its abundance and increased persistence. Microplastics can be classified as either primary, i.e., fabricated for commercial use, or secondary, i.e., resulting from the fragmentation/weathering processes of larger plastic pieces in the environment. In general, microplastics are detected in a number of aquatic organisms (e.g., fish, bivalves, mollusks, etc.) with alarming effects on their health. Therefore, the present work focuses on the detection and identification of microplastics in fish species (Dicentrarchus labrax, Sparus aurata) and mussels (Mytilus galloprovincialis) from aquaculture systems since these aquatic organisms are largely commercially available for consumption. In addition, seawater was also screened for the types of polymers present as well as their aging. The experimental protocol for biota samples contains a digestion step using Fenton’s reagent (0.05 M FeSO4⋅7H2O with 30% H2O2 at a volume ratio of 1:1) to remove organic material followed by filtration and a density separation step where the sample material was mixed with a saturated ZnCl2 solution to separate microplastic particles from heavier material. For seawater samples (sampled by a microplastic net sampler), only sieving on stainless steel sieves followed by filtration on silica filters was applied. Detection of microplastics and identification of their polymeric composition was achieved through the combined use of micro-Raman analysis, Attenuated Total Reflectance–Fourier Transform Infrared spectroscopy, and Scanning Electron Microscopy in tandem with Energy Dispersive X-ray spectroscopy. Microplastic abundance was 16 ± 1.7 items/individual in mussels and 22 ± 2.1 items/individual in sea bass, and 40 ± 3.9 items/individual in sea bream, with polyethylene (74.4%) being the most detected polymer type, while polyethylene-co-vinyl acetate (65%), polyvinyl-butyral (36.8%), polyvinyl alcohol (20%), and polybutyl methacrylate (15.8%) were also detected to a lesser extent. The microplastics isolated from seawater samples were films (30%), fragments (30%), and fibers (20%), while some of them were derived from foams (20%). Also, in most of these seawater-recovered microplastics, a relatively high degree of oxidation (carbonyl index &gt; 0.31) was observed, which was further confirmed by the results of Energy Dispersive X-ray spectroscopy. Finally, the Scanning Electron Microscopy images showed various morphological characteristics (cracks, cavities, and burrs) on the surfaces of the microplastics, which were attributed to environmental exposure.

Excellent low-temperature activity for oxidation of benzene serials VOCs over hollow Pt/CoMn2O4 sub-nanosphere: Synergistic effect between Pt and CoMn2O4 on improving oxygen activation

Constructing the interfacial active sites between noble metals and oxides is an effective way to enhancing the catalytic performance of noble metal-supported catalysts. Meanwhile, ultra-low dosage of the noble metal Pt but obtaining favorable catalytic activity is still major challenge to prepare noble metal-supported catalysts. Herein, the active Pt-CoMn2O4 interface with strong metal-support interaction (SMSI) is designed by loading ultra-low Pt content (0.12 wt%) on hollow structured CoMn2O4 sub-nanosphere (Pt/CoMn2O4). Compared with the reference MnOx, CoMn2O4 and Pt/MnOx, Pt/CoMn2O4 shows excellent catalytic activity even in presence of H2O, which is capable of completely converting toluene, ethylbenzene and o-xylene at 163, 207 and 218 °C, respectively. Various characterizations and density functional theory (DFT) calculations are performed to reveal the role of CoMn2O4 and specify the synergistic effect between Pt and CoMn2O4 on surface properties and catalytic performance. Intriguingly, in situ-designed temperature-programmed techniques and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy clarify the substitution of Co in CoMn2O4 enhances oxygen mobility, and the interface of Pt and support is the active sites for gaseous oxygen activation can also be confirmed by DFT calculation results. This SMSI is prone to promote the supplement of active oxygen species that is essential for excellent low-temperature catalytic oxidation performance. This study provides a new insight into the design of high-performance noble metal catalysts, and the understanding of textural structure, active species, synergistic effect, and mechanisms of catalytic systems.

High-performance CO2 Capture from Air by Harnessing the Power of CaO- and Superbase Ionic Liquid-Engineered Sorbents.

Direct air capture (DAC) of CO2 by solid porous materials represents an attractive "negative emission" technology. However, state-of-the-art sorbents based on supported amines still suffer from unsolved high energy consumption and stability issues. Herein, taking clues from the CO2 interaction with superbase-derived ionic liquids (SILs), high-performance and tunable sorbents in DAC of CO2 was developed by harnessing the power of CaO- and SIL-engineered sorbents. Deploying mesoporous silica as the substrate, a thin CaO layer was first introduced to consume the surface-OH groups, and then active sites with different basicities (e.g., triazolate and imidazolate) were introduced as a uniformly distributed thin layer. The as-obtained sorbents displayed high CO2 uptake capacity via volumetric (at 0.4 mbar) and breakthrough test (400 ppm CO2 source), rapid interaction kinetics, facile CO2 releasing, and stable sorption/desorption cycles. Operando Diffuse Reflectance Infrared Fourier Transformation Spectroscopy (DRIFTS) analysis under simulated air atmosphere and solid-state Nuclear Magnetic Resonance (NMR) under 13CO2 atmosphere demonstrated the critical roles of the SIL species in low-concentration CO2 capture.The fundamental insights obtained in this work provide guidance on the development of high-performance sorbents in DAC of CO2 by leveraging the combined advantages of porous solid scaffolds and the unique features of CO2-philic ILs.

Antimicrobial property of polyethersulfone (PES) membrane by plasma copolymerization of TEOS and oxazoline for organic dyes filtration

Plasma-based surface modification has been regarded as a green method to avoid the usage of toxic solvents in order to introduce various functional groups on the filtration membrane. In this paper, we employ plasma polymerization on the polyethersulfone (PES) ultrafiltration membrane by using simultaneously Tetraethyl orthosilicate (TEOS) and Oxazoline precursor exhibiting superhydrophilic and antibacterial properties to be used for organic dyes filtration. The addition of nanoscale coatings produced by the proposed plasma copolymerization of TEOS and Oxazoline could enhance the overall performance of the membrane in terms of pure water flux and antimicrobial properties compared to untreated sample. We evaluate its chemical composition by using Attenuated Total Reflectance Fourier Transform Infrared (FTIR/ATR) and XPS spectroscopy to ensure the presence of Oxazoline ring and Silicate functional group. Thus, our proposed plasma-modified membrane could be promising to solve specific issues regarding antibiofouling and improve simultaneously its overall performance.

Effect of Acid‐Base Properties of Oxide Catalysts on Glycerol Transformation into Diglycerides

AbstractGlycerol oligomerization in a liquid phase was studied over the acid‐base bifunctional catalysts for the following oxides: TiO2, ZrO2, CeO2, binary CeO2−ZrO2 systems, and purely basic oxide MgO. The phase composition and surface area have been estimated by XRD and BET. The acid and basic properties of catalysts have been characterized using the quasi‐equilibrium thermal desorption (QE‐TD) of NH3 (acidity) and CO2 (basicity). Attenuated total reflectance FTIR (ATR‐FTIR) spectroscopy provided qualitative insights into the interactions in the oxide‐glycerol systems. A comparison of catalytic and acid‐base properties of the oxide systems showed that the reaction requires the presence of both acid and base sites in the catalyst. Moreover, the strength of base sites should exceed the strength of acid sites.

A Thermal Analytical Study of LEGO® Bricks for Investigating Light-Stability of ABS.

Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer widely used in several everyday life applications; moreover, it is also one of the most employed plastics in contemporary artworks and design objects. In this study, the chemical and thermal properties of an ABS-based polymer and its photo-degradation process were investigated through a multi-analytical approach based on thermal, mass spectrometric and spectroscopic techniques. LEGO® building blocks were selected for studying the ABS properties. First, the composition of unaged LEGO® bricks was determined in terms of polymer composition and thermal stability; then, the bricks were subjected to UV-Vis photo-oxidative-accelerated ageing for evaluation of possible degradation processes. The modifications of the chemical and thermal properties were monitored in time by a multi-technique approach aimed at improving the current knowledge of ABS photodegradation, employing pyrolysis online with gas chromatography and evolved gas analysis, coupled with mass spectrometric detection (Py-GC-MS and EGA-MS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and corroborated by external reflection FT-IR spectroscopy. The multimodal approach provided new evidence on the two-step degradation pathway proposed for ABS, defining molecular markers for polybutadiene oxidation and styrene-acrylonitrile depolymerization. Moreover, the results highlighted the feasibility of correlating accurate compositional and thermal data acquired by bulk techniques with external reflection FT-IR spectroscopy as a non-invasive portable tool to monitor the state of conservation of plastic museum objects in-situ.

Enhanced SO2 adsorption performance on nitrogen-doped biochar: Insights from generalized two-dimensional correlation infrared spectroscopy

Nitrogen-doped biochar is considered as a renewable, cost-effective, and promising SO2 adsorbent. However, it is difficult to improve the physicochemical properties of biochar synergistically and clarify the adsorption mechanism. Therefore, in this study, a one-step high-temperature CO2-NH3 modification method was proposed for biochar to improve its SO2 adsorption, and the in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (in situ DRIFTS) was used to reveal the interface reaction mechanism between SO2 and nitrogen-doped biochar. The results showed that when the modification temperature exceeded 700 °C, CO2 and NH3 exhibited significant thermal activation and nitrogen doping on biochar simultaneously. Under a modification temperature of 800 °C (BCAN-800), the microporous surface area and nitrogen content of modified biochar reached the highest value of 563.83 m2/g and 6.63 wt%. The SO2 adsorption capacities of BCAN-800 were up to 201.89 mg/g and 145.68 mg/g at 30 °C and 120 °C, respectively. The results of in situ DRIFTS showed that dimeric and bridge hydrogen bonds were the main SO2 adsorption sites on nitrogen-doped biochar at 30 °C. With the increase of adsorption temperature, nitrogen-containing groups as the main adsorption site could combine with SO2 to form sulfamide (60 °C), which eventually existed in a more stable form of SO42−/R-O-SO2-OR′ (120 °C).

Ga-Modification Near-Surface Composition of Pt-Ga/C Catalyst Facilitates High-Efficiency Electrochemical Ethanol Oxidation through a C2 Intermediate.

In electrochemical ethanol oxidation reactions (EOR) catalyzed by Pt metal nanoparticles through a C2 route, the dissociation of the C-C bond in the ethanol molecule can be a limiting factor. Complete EOR processes producing CO2 were always exemplified by the oxidative dehydrogenation of C1 intermediates, a reaction route with less energy utilization efficiency. Here, we report a Pt3Ga/C electrocatalyst with a uniform distribution of Ga over the nanoparticle surface for EOR that produces CO2 at medium potentials (>0.3 V vs SCE) efficiently through direct and sustainable oxidation of C2 intermediate species, i.e., acetaldehyde. We demonstrate the excellent performance of the Pt3Ga-200/C catalyst by using electrochemical in situ Fourier transform infrared reflection spectroscopy (FTIR) and an isotopic labeling method. The atomic interval structure between Pt and Ga makes the surface of nanoparticles nonensembled, avoiding the formation of poisonous *CHx and *CO species via bridge-type adsorption of ethanol molecules. Meanwhile, the electron redistribution from Ga to Pt diminishes the *O/*OH adsorption and CO poisoning on Pt atoms, exposing more available sites for interaction with the C2 intermediates. Furthermore, the dissociation of H2O into *OH is facilitated by the high hydrophilicity of Ga, which is supported by DFT calculations, promoting the deep oxidation of C2 intermediates. Our work represents an extremely rare EOR process that produces CO2 without observing kinetic limitations under medium potential conditions.

Potential biomarkers for southern African hunter-gatherer arrow poisons applied to ethno-historical and archaeological samples

The detection of complex poison recipes applied to ancient hunting weapons has the potential to provide important insights into traditional pharmacological knowledge systems. Yet, recipes comprising many ingredients can be challenging to decipher, especially in older samples that have undergone biodegradation. We present the results of our attempt to analyze samples of poison collected from nineteenth and twentieth century arrowheads from southern Africa, and from a 1000-year-old archaeological bone point. The arrow poison residues and reference samples were analyzed by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR FTIR) and Gas Chromatography Mass Spectrometry (GC–MS). The ATR FTIR analysis is primarily able to separate between different arrow poison binder recipes. The extractives identified by GC–MS analysis consist of a multitude of components from both binders and active substances, confirming and adding to the results from the ATR FTIR analyses. We discuss the results in terms of potential biomarkers for arrow poisons in organic residue analyses of archaeological artefacts; that residues of toxic cardiotonic glycosides can be detected on curated and excavated arrow tips of between about 1000 and 100 years old, serves as proof of concept for working with older materials in the future.

A biocompatible lipid-based bigel for topical applications

The development of biocompatible delivery systems is a necessity for medical and topical applications. Herein, the development of a new bigel for topical application is described. It is composed of 40% colloidal lipid hydrogel and 60% olive oil and beeswax oleogel. Its characterization and the potential of the bigel as a drug carrier through the skin was evaluated in vitro using fluorescence microscopy and two phases of the bigel were labeled with two fluorescent probes: sodium fluorescein (hydrophilic phase) and Nile red (lipophilic phase). The structure of the bigel showed two phases with fluorescence microscopy in which the hydrogel phase was incorporated into a continuous oleogel matrix. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) presented a combination of vibrations characteristic of the different molecules forming the bigel, and Differential Scanning Calorimetry (DSC) showed different transitions attributed to beeswax lipids. Small-angle and wide-angle X-ray scattering (SAXS and WAXS) indicated a predominant lamellar structure with orthorhombic lateral packing that could be related to the arrangement of beeswax crystals. Bigel enables deeper penetration of hydrophilic and lipophilic probes into deeper layers, making it a promising candidate for effective topical carriers in medical and dermatological applications.

Enhancement of Hydrodearomatization Catalyst by Brönsted Acid Site of Al2O3 Support for Clean Diesel Production

Exhaust from diesel engine contributes a main part in both PM10 and PM2.5 problem. Polycyclic aromatic hydrocarbons (PAHs) in diesel fuel should be considered because of their toxicity. Worldwide Fuel Charter recommends the PAHs content less than 2 wt.% in diesel fuel for less toxic of diesel exhaust emission. Nickle Molybdenum Sulfide over Gamma alumina (NiMoS/γ-Al2O3) catalyst is generally used in hydrotreating processes of petroleum refinery. PAHs are saturated by hydrogenation reaction (HYD) to be mono-aromatic or non-aromatic, called Hydrodearomatization (HDA) process. However, NiMoS/γ-Al2O3 catalysts still require improvements of HYD activities. Gamma alumina has been widely used as catalyst support, which generally possesses only Lewis acidity. This work focuses on surface modification of γ-Al2O3 by ammonium fluoride to generate Brönsted acidity, which could improve HYD function of NiMoS catalysts. All γ-Al2O3 supports were characterized by In-situ pyridine adsorption Diffuse Reflectance Infrared Fourier Transform spectroscopy (Pyridine-DRIFT). Increment of fluorine content in the modified γ-Al2O3 leads to increase its Brönsted acidity. The NiMoS over modified γ-Al2O3 exhibits higher HYD activities than that of the γ-Al2O3. Generation of Brönsted acidity on ϒ-Al2O3 support can enhance the HYD function of NiMoS catalyst for HDA process of clean diesel production.

Ohmic-functionalized type I heterojunction: Improved alkaline water splitting and photocatalytic conversion from CO2 to C2H2

A hollow dodecahedron-shaped N-doped carbon (N-C) coated with CoSe2 nanoparticles are fabricated via MOF-derived self-sacrificing strategy based on Kirkendall Effect. By coupling with CdS nanodots, the optimal Ohmic-type functionalized type I heterojunction CdS/N-C/CoSe2 (CCE50) exhibits a significant photocatalytic hydrogen evolution reaction (PHER) rate of 19317.3 μmol h−1 gcat−1 that is 15.7 and 33.7 folds higher than type I CdS/N-C heterojunction (1230.3 μmol h−1 gcat−1) and pure CdS respectively, and successfully transfers the source of photo-corrosion to obtain stable PHER for 5 cycles. Moreover, the CCE50 in alkaline media (pH = 12) achieves a 1.6-fold PHER rate higher than that in the original triethanolamine (TEOA) aqueous solution (pH≈8), where electron paramagnetic resonance (EPR) result shows that it is attributed to the accumulation of O2–. The effective PHER rate can be attributed to the synergistic effect of higher light absorption in hollow CCE50 with multiple scattering and the introduction of Ohmic contact. Besides, the successful conversion from CO2 to C2H2 under 80 kPa CO2 pressure is detected firstly on CdS-based photocatalyst (the conversion rate is 2.8 μmol h−1 gcat−1) without other C1 or C2 gas products. EPR, in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) tests, Kelvin Probe Force Microscopy (KPFM) and density functional theory calculations, etc. have illustrated and verified the photocatalytic mechanism for Ohmic contact-enhancing type I heterojunction, which promotes hydrogen production in alkaline media and C2H2 generation from CO2.

Combined effects of high hydrostatic pressure and chemical pre‐treatment on physico‐chemical properties of beef, using FTIR and diffuse reflectance spectroscopy

AbstractHigh pressure processing (HPP) was combined with a previous short chemical treatment to stabilize the color of beef tissue. Beef samples were treated with a solution containing ascorbic acid, sodium chloride, and a very low concentration of sodium nitrite. The effects of pressure levels (0.1–600 MPa) and preservative solution on: (i) color properties based on diffuse reflectance spectroscopy (DRS), which determines the relative concentrations of muscle pigments, (ii) protein denaturation and changes in the secondary structures by DSC and FTIR‐ATR, were determined.At high pressures, the disappearance of DSC peaks due to protein denaturation, a decrease in the proportion of α‐helix and an increase in the percentage of disordered structures, were evidenced. DRS spectra and Kublelka‐Munk theory equations demonstrated that nitrosilmyoglobin was a more stable chromophore, decreasing discoloration of the tissue. These techniques contribute to the knowledge of the physico‐chemical properties of the tissue submitted to combined preservation processes.Practical ApplicationsThere is an increasing demand from consumers for high‐quality beef products, with significant emphasis placed on color and safety attributes. Extending the shelf life by applying high hydrostatic pressure treatment (HHP) improves food safety and will produce a positive impact on both the industry and consumers. HHP is a non‐thermal preservation technology with generally minimal effects on sensory qualities and nutritional content; however, the direct application of this technology on beef leads to the production of a product with an unacceptable pale coloration. Therefore, it must be remarked that a pre‐treatment stage by immersing the pieces in a preservative solution is essential to improve the color of beef products treated by HHP. In this regard, from a technological point of view, it is very important to know the combined effects of both stages (short chemical treatment and high‐pressure) on the quality of beef products.

Effect of titanium oxide nanoparticles on polymerization reaction of heat and microwave cured polymethylmethacrylate: in vitro study

BackgroundTitanium Oxide Nanoparticles (TiO2NPs) have been introduced to polymethyl methacrylate (PMMA) denture base to enhance its mechanical, physical, and biological performance.ObjectivesThis research aimed to assess the effect of adding TiO2NPs on the degree of polymerization and morphological characterization of heat and microwave cured PMMA.Materials and methodsFabrication of PMMA specimens which were categorized according to the curing technique into heat cured (group I) and microwave cured (group II). Each group was subdivided into two subgroups A and B according to the addition of TiO2NPs. A total number of 24 specimens were fabricated. Each subgroup contains 6 specimens. The specimens were characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). The polymerization reaction of specimens was assessed by Attenuated Total Reflection Fourier-Transform Infra-Red Spectroscopy (ATR-FTIR). Results were statistically analyzed using an independent T-test and one-way ANOVA. The significance level was set at p < 0.05.ResultsSEM/EDX revealed that TiO2 NPs appeared as bright areas in the matrix of both groups. The matrix showed organic impurities and minute internal cracks, but group IIB (microwave-cured PMMA with TiO2NPs) showed higher organic impurities than heat-cured PMMA. The FTIR revealed that the addition of 3% by weight TiO2NPs decreased the degree of polymerization of both heat and microwave-cured PMMA but the decrease was insignificant (p > 0.05).ConclusionsIncorporation of 3% by weight TiO2NPs does not significantly affect the degree of polymerization of both heat and microwave-cured PMMA. Hence, denture materials can benefit from the advantages of the TiO2NPs without any alterations to their structures.Graphical abstract

INFRA-ART: An Open Access Spectral Library of Art-related Materials as a Digital Support Tool for Cultural Heritage Science

Easily accessible characterization techniques such as X-ray fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), or Raman spectroscopy, are at this moment the most commonly used analytical tools in heritage and conservation science. Materials identification in works of art is a fundamental step for understanding an object's history or an artist's technique. Comprehensive characterization and diagnosis of the various constituent materials in artworks can provide valuable information on the artist's working methods, as well as significant evidence for dating, provenance attribution, or forgery detection. The development of databases with high-quality data on the pure substances used as artists’ materials is of utmost importance for the identification and characterization of unknown samples. However, there are relatively few open access spectra libraries dedicated exclusively to the cultural heritage field. To address this need, within the frame of the postdoctoral project INFRA-ART, an open access spectral library of art-related materials has been developed. The database is an ongoing compilation of spectra that contains at this moment over 1,000 high-quality attenuated total reflection–FTIR, Raman, and XRF spectra associated with over 500 known reference materials. In this article, a summary of the database structure and design, functionality, and use is presented, in view of the dissemination of this new open access spectral library to the scientific community.

Catalytic upgrading of bio-oil model mixtures in the presence of microporous HZSM-5 and γ-Al2O3 based Ni, Ta and Zr catalysts

Bio-fuel production from bio-oil was investigated in the presence of microporous HZSM-5 and Al2O3 (MA) based catalysts. This study focused on the catalytic upgrading of a model bio-oil compound with ethanol for bio-fuel production. The model compound containing hydroxypropanol/furfural/formic acid: 4/6.5/5 by volume was used as a bio-oil mixture. Activity tests were performed under atmospheric pressure with a volumetric feed ratio of 30/70 bio-oil mixture/ethanol using a 0.5 g catalyst. In the reaction studies performed on the commercial microporous HZSM-5 catalyst, the optimum co-cracking temperature was determined as 400 °C. Mesoporous γ-Al2O3 support was synthesized by the evaporation-induced self-assembly (EISA) synthesis method, and Ni, Ta, and Zr metals were incorporated into the structure of the catalyst by the impregnation method to improve the surface acidity. The synthesized catalysts were characterized by X-ray diffraction (XRD), X-ray absorption near edge spectroscopy (XANES), N2 adsorption–desorption, scanning electron microscopy energy dispersive spectroscopy (SEM/EDS), X-ray fluorescence (XRF), Fourier-transformed infrared spectroscopy (FTIR), pyridine adsorbed diffuse reflectance FTIR spectroscopy (DRIFTS), and thermogravimetric/differential thermal analysis (TGA-DTA). Monometallic and pure alumina catalysts indicated an ordered mesoporous structure with surface area values 106–389 m2/g. Lewis and Brønsted acid sites associated with mild acidity were observed in the DRIFTS results of the 10 wt% Zr-containing alumina catalyst (10Zr@MA). The highest oil phase selectivity and isoparaffin selectivity in oil phase values were obtained in the presence of 10Zr@MA as 17.22% and 80.96%, respectively. 10Zr@MA catalyst showed the best catalytic activity compared to other catalysts, with 9.54% coke formation.

Carotenoids contribution in rapid diagnosis of multiple sclerosis by Raman spectroscopy

Rapid and accurate diagnosis of any illness determines the success of treatment. The same applies to multiple sclerosis (MS), chronic, inflammatory, and neurodegenerative diseases (ND) of the central nervous system (CNS). Unfortunately, the definitive diagnosis of MS is prolonged and involves mainly clinical symptoms observation and magnetic resonance imaging (MRI) of the CNS. However, as we previously reported, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy shed new light on the minimally invasive, label-free, and rapid diagnosis of this illness through blood fraction. Herein we introduce Raman spectroscopy coupled with chemometric analysis to provide more detailed information about the biochemical changes behind MS. This pilot study demonstrates that mentioned combination may provide a new diagnostic biomarker and bring closer to rapid MS diagnosis. It has been shown that Raman spectroscopy provides lipid and carotenoid molecules as useful biomarkers which may be applied for both diagnosis and treatment monitoring.