Fourier Transform Infrared Spectroscopy Data Research Articles

ABS/AgZrP Nanocomposite Additive Manufacturing Filament for Antibacterial Applications

The emergence of COVID-19 raised awareness in hygiene practices and reminded us of the harm that microbes bring to our health. Incorporating antibacterial agents in polymeric materials would allow us to combat lingering bacteria on surfaces that we often use. The utilization of composite filaments with antibacterial activity would allow us to employ better precautions in reducing contact with harmful bacteria. Antibacterial acrylonitrile‐butadiene‐styrene (ABS) nanocomposites were prepared by incorporating silver zirconium phosphate (AgZrP) nanoparticles via twin screw extruder. The ABS/AgZrP nanocomposite filament with 5 wt % and 20 wt% of AgZrP were synthesized and characterized with Differential scanning calorimetry (DSC), Thermogravimetric Analysis (TGA), X-ray diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FTIR). DSC and XRD data denote an increase in the presence of crystalline regions as the AgZrP content is increased. TGA data indicate that the addition of AgZrP has no effect on the thermal stability of the material. FTIR data indicate a decrease in transmission at higher AgZrP loading. The decreasing trend in tensile properties of the 3D-printed neat and AgZrP-filled ABS may have been due to particle agglomeration acting as stress concentrators. Antibacterial activity assessment via disk diffusion test showed a zone of inhibition within the sample indicating that there is no bacterial growth both for Escherichia coli and Staphylococcus aureus.

How does soil organic matter stabilize with soil and environmental variables along a black soil belt in Northeast China? An explanation using FTIR spectroscopy data

Chemical composition of soil organic matter (SOM) is an important determinant of SOM stabilization and soil function. Better understanding of the chemical composition of SOM is vital for assessing soil formation processes and its controlling factors. Fourier transform infrared (FTIR) spectroscopy was applied to characterize the chemical compositions of SOM for 234 surface soils collected from a representative black soil belt in Northeastern China. The relationships of SOM chemical composition with soil and environmental variables were assessed. Soil samples were divided into eight regional groups and four soil organic carbon (SOC) range groups according to the administrative division and SOC contents, respectively. Generally, SOC contents varied from 8.2 to 34.5 g kg−1, together with the relative abundances of aliphatic-C increased from the south to the north along the black soil belt, while the relative abundance of aromatic-C decreased. Total nitrogen (TN), relative abundance of polysaccharide-C, and minerals showed no obvious zonal changes. In four SOC range groups, averaged SOC, TN, and aliphatic-C increased significantly with increasing SOC contents, while the aromatic-C decreased (P < 0.05). The polysaccharide-C and minerals also increased. Correlation analysis showed that SOC was positively related with aliphatic-C, and negatively related with aromatic-C regardless of regions and SOC contents (P < 0.05). Principal component analysis demonstrated obvious separations among soils divided into four SOC ranges compared to those divided into eight regions. SOC, TN, and aliphatic-C pointing to SOC > 20.0 g kg−1 groups, and aromatic-C pointing to SOC < 15.0 g kg−1 groups were the main driving factors via PC1. The aromatic-C/aliphatic-C ratio representing SOM decomposition degree, mean air temperature, and precipitation pointing to SOC < 10.0 g kg−1 groups, and minerals were the main driving factors via PC2. Our results contribute to a further understanding of spatial variations in SOM chemical compositions regarding soil formation and SOC stabilization caused by environmental conditions and agricultural managements.

A regularised logistic regression model with structured features for classification of geographical origin in olive oils

Geographical origin of extra virgin olive oil is a factor that consumers may take into account when making purchasing decisions. Oils that are labelled to be from regions famous for olive cultivation may be assumed to be of higher quality. However, difficulties in the authentication of the geographical origin of olive oils arise due to the similarity in chemical compositions of the oils involved. Fourier-transform infrared (FTIR) spectroscopy has been found to be a viable technology for the classification of oil samples by geographical origin. However, classical methods involving dimension reduction before model fitting usually yield models that are more challenging to interpret. Sparse fused group lasso logistic regression (SFGL-LR) is used with FTIR spectroscopic data to discriminate between Greek and non-Greek organic extra-virgin olive oils. The prediction performance is also compared with that obtained by partial least squares linear discriminant analysis (PLS-LDA). While both methods give comparable good prediction performance, with more than 90% accuracy in classification, the SFGL-LR model demonstrates improvements in the interpretability of the model coefficients.

Polyphenols in Jabuticaba (Plinia spp.) Peel Flours: Extraction and Comparative Evaluation of FTIR and HPLC for Quantification of Individual Compounds

Jabuticabas are wild fruits native to Brazil, and their peels, the main residue from jabuticaba processing, contain significant amounts of bioactive compounds, which are mostly phenolics. Conventional methods based on the estimation of total extractable phenolics (TEP-Folin-Ciocalteau) or total monomeric anthocyanins (TMA) have limitations and may not reflect the actual antioxidant potential of these peels. Analytical methods, such as high-performance liquid chromatography (HPLC), are more appropriate for the quantification of specific phenolics, and can be used as a reference for the construction of mathematical models in order to predict the amount of compounds using simple spectroscopic analysis, such as Fourier Transform Infrared Spectroscopy (FTIR). Therefore, the objectives of this study were (i) to evaluate the composition of specific polyphenols in flours prepared from jabuticaba peels and verify their correlation with TEP and TMA results from a previous study, and (ii) to employ FTIR coupled with chemometrics to predict the concentrations of these polyphenols in jabuticaba peel flours (JPFs) using HPLC as a reference method. Cyanidin-3-glucoside (C3G), ellagic acid (EA) and delphinidin-3-glucoside (D3G) were the main polyphenols found in the samples. The C3G contents ranged from 352.33 mg/100 g (S10) to 1008.73 mg/100 g (S22), with a strong correlation to TMA (r = 0.97; p = 0.00) and a moderate correlation to TEP (r = 0.45; p = 0.02). EA contents ranged from 163.65 mg/100 g (S23) to 334.69 mg/100 g (S11), with a moderate to strong correlation to TEP (r = 0.69; p = 0.00). The D3G values ranged from 94.99 mg/100 g (S10) to 203.36 mg/100 g (S5), with strong correlations to TMA (r = 0.91; p = 0.00) and C3G levels (r = 0.92; p = 0.00). The developed partial least squares-PLS models based on FTIR data provided satisfactory predictions of C3G and EA levels, reasonably matching those of HPLC.

Synthesis and characterization of natural biomaterial composite nanofibers for ocular drug delivery systems

Due to its numerous reported benefits, including biomimetic, immunomodulation, and compatibility with tissue microenvironment, natural bio composite nanomaterials are in demand as an effective replacement in the field of tissue engineering. As a result, in this study, we investigated polysaccharides containing natural materials from Coriandrum sativum(CS) and Trigonella foenum-graecum(TFG) to create a composite nanofiber matrix with polyvinyl alcohol (PVA). Drug-free and drug-containing versions of the natural composite nanofiber have been developed. Zeta potential, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy were used to characterize the conductivity, molecular makeup and size of the fibers (SEM). Brunauer-Emmett-Teller (BET) analysis was used to determine the topography of the surface. To determine how natural biomaterials will affect PVA, the stiffness of the composite nanofibers was tested. Drug release from the PVA composite nanofiber matrix using HPLC analysis was conducted on fibers loaded with drugs. Primary Human tenon fibroblast cells were used to test the fibers biocompatibility. SEM analysis revealed that bead-free composite nanofibers had homogeneous dimensions ranging from 150 nm to 200 nm. The presence of heterogeneous molecules from the natural material was revealed by FTIR data in the composite nanofiber. According to the BET analysis, the addition of natural biomaterial significantly altered the surface topography. With the addition of the drug 5-Fluorouracil, the stiffness of PVA nanofibers decreased from 103 ± 6 to 70 ± 15 Kpa. At the same time, the drug improved the mechanical properties of the composite nanofiber mats, increasing stiffness from 150 ± 22 Kpa to 180 ± 17 Kpa. Human Tenon fibroblast Cell toxicity assay showed that there was a difference in the cell viability of the composite nanofibers with the drug. The release kinetics of HPLC data showed that the composite matrix fibre mat had sustained drug release for 4 hrs. Cell viability assay findings revealed that composite nanofibers did not have any significant effect on the cell viability. Further research on the toxicity of the composite material in vivo is required to determine the mechanism. This may be helpful in modulating fibrosis process post trabeculectomy surgery.

Effect of heat treatment on structural properties of CeO2 prepared by chemical-route method

The chemical-route auto combustion method was used to prepare Cerium oxide (CeO2) powder for different applications in the electronic and automobile sector. These experiments were carried out on two different cases, before and after calcination at 900 °C. The calcination process involves heating the samples to high temperatures to remove the impurities; we examined the different structural and morphological analyses to see whether the effect of heat treatment with the given temperature affected the sample. The structural analysis of the product material was performed using X-ray diffraction (XRD), scanning electron microscope (SEM), which provided morphological details, and the compositional analysis was confirmed using Energy Dispersive Spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR), which was used to determine the different functional groups present in the product material. Based on the XRD spectra, prepared CeO2 powder showed crystalline with cubic structure. The rise in crystalline size with respect to an increase in calcinated temperature was supported by the consistency between theoretical and experimental findings, SEM pictures show that the shape of the particles changes to a sphere-like structure with less aggregated as the temperature rises. The Ce-O stretching mode of CeO2 was demonstrated using FTIR data. the thermal treatment lowered the carbon s atomic fraction as anticipated, as seen by the EDS spectra of the annealed CeO2 samples.

Use of Fourier transform infrared spectroscopy and multi-variant analysis for detection of butter adulteration with vegetable oil

ABSTRACT During butter manufacturing, adulteration of animal and plant fats is one of the major issues in dairy industries. In dairy products, there is a huge potential in spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR) for the rapid determination of various adulterants. These spectroscopic techniques are reliable, rapid, and accurate as compared to traditional methods. Therefore, the aim of this study was to measure the potential of FTIR spectroscopy along with mathematical modeling for the detection of vegetable oil in butter samples. In this study, different levels of vegetable oil were added to the butter. FTIR spectra of different samples were collected and processed using principal component analysis (PCA) as well as partial least square (PLS) regression. PCA results postulated that 98% of the total variance was accounted by the first two principal components (PC) with a predominance of PC 1 (85%). PLS regression analysis showed values of R2 for calibration as 0.95 and R2 for validation as 0.90 which described good prediction efficiency of vegetable oil adulteration through FTIR data. The present work summarized that Fourier transform infrared spectroscopy along with multivariate analysis can be used to measure the adulteration in butter.

Studying the Intermolecular Interactions, Structural Dynamics, and Non-Equilibrium Kinetics of Cilnidipine Infiltrated into Alumina and Silica Pores.

In the present study, the behavior of the calcium channel blocker cilnidipine (CLN) infiltrated into silica (SiO2) and anodic aluminum oxide (AAO) porous membranes characterized by a similar pore size (d = 8 nm and d = 10 nm, respectively) as well as the bulk sample has been investigated using differential scanning calorimetry, broadband dielectric spectroscopy (BDS), and Fourier-transform infrared spectroscopy (FTIR) techniques. The obtained data suggested the existence of two sets of CLN molecules in both confined systems (core and interfacial). They also revealed the lack of substantial differences in inter- and intramolecular dynamics of nanospatially restricted samples independently of the applied porous membranes. Moreover, the annealing experiments (isothermal time-dependent measurements) performed on the confined CLN clearly indicated that the whole equilibration process under confinement is governed by structural relaxation. It was also found that the βanneal parameters obtained from BDS and FTIR data upon equilibration of both confined samples are comparable (within 10%) to each other, while the equilibration constants are significantly different. This finding strongly emphasizes that there is a close connection between the inter- and intramolecular dynamics under nanospatial restriction.

Preparation of Biosorbent from Kapok Fruit Peel (Ceiba pentandra) for Adsorption of Lead Waste

The preparation of biosorbent from kapok fruit peel (KBK) for lead (Pb(II)) removal was conducted mechanically by expanding the surface of the biosorbent and activating KBK with the addition of 1 M HCl for 20 minutes. The effect of activation on increasing the number of active groups and the number of pores in the biosorbent was proven by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The FTIR data showed a shift and an increase in wavenumber intensities of active adsorbent groups such as -OH and -C=O. The SEM data revealed that the morphology of the adsorbent increased in the number of pores that appeared rough and irregular. The Pb(II) adsorption treatment used a batch method at pH 2–5, contact time of 0–120 minutes, and adsorbate concentration of 10–50 ppm. The adsorption of Pb(II) ions reached optimum conditions at pH 4 and a contact time of 60 minutes, with an adsorption capacity of 6.9522 mg/g and an adsorption rate of 98.71%. Adsorption data showed that Pb(II) ions uptake to KBK biosorbent followed the Langmuir isotherm model equation and pseudo-second-order kinetic model. The adsorption capacity of activated KBK is greater than that of non-activated KBK.

In-process real-time probiotic phenotypic strain identity tracking: The use of Fourier transform infrared spectroscopy.

Probiotic bacteria, capable of conferring benefits to the host, can present challenges in design, development, scale-up, manufacturing, commercialization, and life cycle management. Strain identification is one of the main quality parameters; nevertheless, this task can be challenging since established methodologies can lack resolution at the strain level for some microorganisms and\or are labor-intensive and time-consuming. Fourier transform infrared spectroscopy (FTIRS) has been largely used for the investigation of pathogenic species in the clinical field, whereas only recently has been proposed for the identification of probiotic strains. Within the probiotic industrial production, bacterial strains can be subjected to stressful conditions that may affect genomic and phenotypic characteristics; therefore, real-time monitoring of all the sequential growth steps is requested. Considering the fast, low-cost, and high-throughput features, FTIRS is an innovative and functional technology for typing probiotic strains from bench-top experiments to large-scale industrial production, allowing the monitoring of stability and identity of probiotic strains. In this study, the discriminatory power of FTIRS was assessed for four Lactiplantibacillus plantarum probiotic strains grown under different conditions, including temperatures (30 and 37°C) and medium (broth and agar), after consecutive sub-culturing steps. A comparison between the generated spectra with pulsed-field gel electrophoresis (PFGE) profiles was also performed. FTIRS was not only able to distinguish the strains of L. plantarum under different growth conditions but also to prove the phenotypic stability of L. plantarum type strain LP-CT after six growing steps. Regardless of the growth conditions, FTIRS spectra related to LP-CT constituted a unique hierarchical cluster, separated from the other L. plantarum strains. These results were confirmed by a PFGE analysis. In addition, based on FTIRS data, broth cultures demonstrated a higher reproducibility and discriminatory power with respect to agar ones. These results support the introduction of FTIRS in the probiotic industry, allowing for the step-by-step monitoring of massive microbial production while also guaranteeing the stability and purity of the probiotic strain. The proposed novel approach can constitute an impressive improvement in the probiotic manufacturing process.

Isolation, Characterization of Banana Starch and its Evaluation as a Disintegrating Agent in Dispersible Lornoxicam Tablet

Objective: The present study was designed to isolate, characterize, formulate, and evaluate the disintegration properties of banana starch in dispersible Lornoxicam tablet formulation. Methods: The alkaline extraction method used sodium hydroxide as a lye solution to isolate starch from unripe banana fruit. Starch was subjected to characterization for physicochemical properties, viscosity and flow properties, Fourier-transform infrared spectroscopy (FTIR) scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray crystallography (XRD) study. Flow properties of starch were determined as per the standard procedure. Tablets were formulated by a wet granulation method using starch as a disintegrant, and the in-vitro release characteristic of the prepared tablets was analyzed. Different concentrations of isolated starch were studied for disintegrating properties compared to corn starch. Results: Studies indicate that starch obtained is qualitatively and quantitatively comparable to corn starch. SEM, FTIR, DSC and XRD data confirmed the polysaccharide nature of the starch. The physicochemical properties of starch passed the prescribed evaluation tests for tablets. These tablets also confirmed the disintegration and dissolution specifications as per Indian Pharmacopoeia. Conclusion: From the above study, it can be concluded that starch obtained from banana shows qualitatively and quantitatively good disintegration characteristics compared to corn starch. These tablets also confirmed a significant degree of dissolution as per the standards. Evaluations also specified that banana starch possesses acceptable disintegrating characteristics compared to corn starch and can be used as a disintegrant in tablet formulation.

Microstructure, Chemical Bonds, and Photocatalyst Activity of Neodymium-doped Strontium Titanate (Sr0.97Nd0.03TiO3) with 900°C and 1000°C Sintering Temperature

Strontium Titanate is a perovskite oxide with remarkable properties as a photocatalyst. The synthesis of Strontium Titanate material with Neodymium doping (Sr0.97Nd0.03TiO3) has been completed by means of the co-precipitation procedure. Samples were sintered at temperatures of 900°C and 1000°C for 4 hours to investigate their properties. X-Ray Diffraction (XRD), Fourier-Transform Infrared spectroscopy (FTIR), and UV-Vis Spectrophotometer were employed to observe the microstructure, chemical bonds, and photocatalyst activity of Sr0.97Nd0.03TiO3. XRD data exhibited that the crystal size enlarged from 42.3 nm and 64.4 nm as the sintering temperature increased. FTIR data revealed strong Sr-Ti-O bonds and decreased C-H and C=H bond impurities as the sintering temperature increased. The photocatalytic performance was evaluated with methylene blue (MB) dye degradation by UV light irradiation for 3, 4, and 5 hours where the UV-Vis spectrophotometer tested the absorbance of the degraded MB. The results exhibited that Sr0.97Nd0.03TiO3 achieved the optimal degradation (62.7%) at 900°C and with 3 hours of irradiation.

Retrieval of atmospheric CFC-11 and CFC-12 from high-resolution FTIR observations at Hefei and comparisons with other independent datasets

Abstract. Synthetic halogenated organic chlorofluorocarbons (CFCs) play an important role in stratospheric ozone depletion and contribute significantly to the greenhouse effect. In this work, the mid-infrared solar spectra measured by ground-based high-resolution Fourier transform infrared spectroscopy (FTIR) were used to retrieve atmospheric CFC-11 (CCl3F) and CFC-12 (CCl2F2) at Hefei, China. The CFC-11 columns observed from January 2017 to December 2020 and CFC-12 columns from September 2015 to December 2020 show a similar annual decreasing trend and seasonal cycle, with an annual rate of -0.47±0.06 % yr−1 and -0.68±0.03 % yr−1, respectively. So the decline rate of CFC-11 is significantly lower than that of CFC-12. CFC-11 total columns were higher in summer, and CFC-12 total columns were higher in summer and autumn. Both CFC-11 and CFC-12 total columns reached the lowest in spring. Further, FTIR data of NDACC (Network for the Detection of Atmospheric Composition Change) candidate station Hefei were compared with the ACE-FTS (Atmospheric Chemistry Experiment Fourier transform spectrometer) satellite data, WACCM (Whole Atmosphere Community Climate Model) data, and the data from other NDACC-IRWG (InfraRed Working Group) stations (St. Petersburg, Jungfraujoch, and Réunion). The mean relative difference between the vertical profiles observed by FTIR and ACE-FTS is -5.6±3.3 % and 4.8±0.9 % for CFC-11 and CFC-12 for an altitude of 5.5 to 17.5 km, respectively. The results demonstrate that our FTIR data agree relatively well with the ACE-FTS satellite data. The annual decreasing rate of CFC-11 measured from ACE-FTS and calculated by WACCM is -1.15±0.22 % yr−1 and -1.68±0.18 % yr−1, respectively. The interannual decreasing rates of atmospheric CFC-11 obtained from ACE-FTS and WACCM data are higher than that from FTIR observations. Also, the annual decreasing rate of CFC-12 from ACE-FTS and WACCM is -0.85±0.15 % yr−1 and -0.81±0.05 % yr−1, respectively, close to the corresponding values from the FTIR measurements. The total columns of CFC-11 and CFC-12 at the Hefei and St. Petersburg stations are significantly higher than those at the Jungfraujoch and Réunion (Maïdo) stations, and the two values reached the maximum in local summer or autumn and the minimum in local spring or winter at the four stations. The seasonal variability at the three stations in the Northern Hemisphere is higher than that at the station in the Southern Hemisphere.

Broadband spectroscopy of astrophysical ice analogues

Context. Broadband optical constants of astrophysical ice analogues in the infrared (IR) and terahertz (THz) ranges are required for modeling the dust continuum emission and radiative transfer in dense and cold regions, where thick icy mantles are formed on the surface of dust grains. Such data are still missing from the literature, which can be attributed to the lack of appropriate spectroscopic systems and methods for laboratory studies. Aims. In this paper, the THz time-domain spectroscopy (TDS) and the Fourier-transform IR spectroscopy (FTIR) are combined to study optical constants of CO and CO2 ices in the broad THz-IR spectral range. Methods. The measured ices were grown at cryogenic temperatures by gas deposition on a cold silicon window. We developed a method to quantify the broadband THz-IR optical constants of ices, based on the direct reconstruction of the complex refractive index of ices in the THz range from the TDS data and the use of the Kramers-Kronig relation in the IR range for the reconstruction from the FTIR data. Uncertainties introduced by the Kramers-Kronig relations were eliminated by merging the THz and IR spectra. Finally, the reconstructed THz-IR response was analyzed using classical models of complex dielectric permittivity. Results. The complex refractive index of CO and CO2 ices deposited at the temperature of 28 K was obtained in the range of 0.312.0 THz and fitted using the analytical Lorentz model. Based on the measured dielectric constants, opacities of the astrophysical dust with CO and CO2 icy mantles were computed. Conclusions. The method developed in this work can be used for a model-independent reconstructions of optical constants of various astrophysical ice analogs in a broad THz-IR range. Such data can provide important benchmarks for interpreting broadband observations from existing and future ground-based facilities and space telescopes. The reported results will be useful in modeling sources that exhibit a drastic molecular freeze-out, such as the central regions of prestellar cores and mid-planes of protoplanetary disks, as well as CO and CO2 snow lines in disks.

Fabrication of Europium-Doped Barium Titanate/Polystyrene Polymer Nanocomposites Using Ultrasonication-Assisted Method: Structural and Optical Properties.

In the current work, europium-doped barium titanate particles were used as filler material and polystyrene was used as a matrix to fabricate Ba1-3x/2EuxTiO3/PS polymer nanocomposites with x = 0, 0.005, 0.015 and 0.025. A solid-state reaction was used to synthesize filler particles and the solvent evaporation method was used to form polymer nanocomposites. The effects of ultrasonic treatment were also studied in the formation of nanocomposite materials. The quantitative and qualitative studies were conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and ultraviolet-visible (UV-Vis) characterization techniques. The XRD data and FTIR data confirm the incorporation of filler particles in the polymer matrix. FE-SEM data confirms that the particles are in the nanophase. The optical band gap was directly affected by the filler particles and it started to reduce as Eu concentration started to increase.

Green Synthesis of Silver Nanoparticles (AgNPs) of Angelica Gigas Fabricated by Hot-Melt Extrusion Technology for Enhanced Antifungal Effects.

Green synthesis for synthesizing silver nanoparticles (AgNPs) has been suggested as an environmentally friendly alternative to conventional physical/chemical methods. In this study, we report the green synthesis of AgNPs using a hot-melt extrusion-processed Angelica gigas Nakai (AGN) (HME-AGN) extract as a reducing agent to increase the water solubility of the active ingredient compared to the existing AGN. The mixture of the AGN extract and AgNO3 at about 420 nm could not confirm the formation of AgNPs. The synthesis of AgNPs was found to be most advantageous at 60 °C when the mixing ratio of the HME-AGN extract was 9:1 (AgNO3–extract, v/v) using 3 mM AgNO3. The physicochemical properties of the optimized AgNPs were characterized by UV–Vis spectrophotometer, dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffractometer (XRD). DLS showed the particle size average of 102.3 ± 1.35 nm and polydispersity index (PDI) value of 0.314 ± 0.01. The particle surface charge was −35 ± 0.79 mV, confirming the stability of the particles. The particle shape was spherical, as shown through TEM analysis, and the presence of silver ions was confirmed through the EDS results. FT-IR data showed functional groups of biomolecules of the extract involved in the synthesis of AgNPs. The face-centered cubic (FCC) lattice of AgNPs was confirmed in the XRD pattern. The AgNPs had an effective antifungal activity against Candida albicans (C. albicans) that was better than that of the HME-AGN extract. In conclusion, this study suggests that the synthesis of AgNPs was improved by using the HME-AGN extract with increased water solubility through HME. In addition, it was suggested that the synthesized AgNPs can be used as an improved antifungal agent compared with the HME-AGN extract with antifungal activity.

Chemometric and Machine Learning Analysis of Lithium Concentration and Solvation Behavior in Li-Ion Battery Electrolytes

The demand for batteries is rapidly growing across a range of technologies. The increasingly diverse use cases for batteries require various capabilities, particularly requirements for high energy densities, that are currently unmet by traditional Li-ion batteries. Electrolyte stability proves to be a bottleneck for battery advancement towards energy dense chemistries beyond Li-ion, including metal anodes. In situ spectroscopy tools, such as Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray spectroscopy, have provided insight into critical molecular-level interactions in batteries during cycling. These in situ tools have yielded continuous improvement of electrolyte properties. Spectroscopy datasets, however, contain many nuances that challenge meaningful human understanding. Artificial intelligence and chemometric tools can be coupled with in situ spectroscopy to find relevant interpretations of spectral datasets and elucidate complex molecular phenomena. In this research, an analysis was performed on FTIR spectroscopy data from an electrolyte composed of LiPF6 in ethylene carbonate (EC) and ethyl methyl carbonate (EMC) to discern solvation behavior using principal component analysis (PCA) and a convolutional neural network (CNN). PCA pinpointed exact band locations of solvation shifting behavior in the IR spectra and improved understanding of the relationship between lithium concentrations and peak changes. The CNN was trained with spectral datasets of electrolytes with known lithium concentrations and then could predict lithium concentrations from spectral datasets with extraordinarily high accuracy. Additionally, the CNN interpreted FTIR spectral datasets from a graphite half-cell with EC/EMC/LiPF6 electrolyte and accurately determined the lithium concentration in the bulk electrolyte. The CNN also observed lithium depletion events (up to 10% lithium depletion) in the graphite anode during fast-charging cycles of the galvanostatic intermittent titration technique. This research breaks new ground on using advanced computational tools for in situ spectroscopic analysis of battery electrolytes and demonstrates an improved understanding of complex molecular-level phenomena in electrolytes.

Evaluation of the Effects of Substrate Heat Treatment and Monomer/Acid Ratio Synthesis Parameters on the Performance of PANI/CFF Electrodes

The association of capacitive charging of the double-layer and a faradic redox reaction is desirable on carbon fiber felt (CFF) when oxygen functional groups or other materials such as conducting polymers are present on its surface enhancing its capacitive properties. In this work, a systematic study of the composites formed by carbon fiber felt felt produced at two different heat treatment temperatures (HTT) of 1000 and 2000 ºC and polyaniline (PANI) was performed upon two approaches: influence of heat treatment temperatures of substrate CFF and monomer/acid ratio. CFF samples were produced from polyacrylonitrile (PAN) precursor at HTT of 1000 and 2000 ºC, with step temperature of 330 ºC h-1 under nitrogen atmosphere. The maximum level temperature was kept for 30 min and then, cooled down to room temperature. The CFF samples were cut in 1 cm2 with thickness about 2 mm. Afterwards, the PANI was electrodeposited on CFF under galvanostatic mode with current density of 5 mA cm-2, using 1:1 and 2:1 H2SO4/aniline mol L-1 aqueous solution at deposition time of the 1350 seconds, for both proportions acid/monomer. The obtained PANI/CFF binary composite was washed in acid solution and vacuum dried. The morphological and structural analyses were investigated by Field emission gun-scanning (FEG-SEM), Surface Area Analysis (BET – Brunauer, Emmett and Teller), Thermogravimetric analysis (TG) and Fourier-Transform Infrared Spectroscopy (FT-IR). Electrochemical responses were analyzed by galvanostatic charge/discharge, electrochemical impedance spectroscopy, and cyclic voltammetry.The electrochemical analyses are recorded in a three electrodes system using Ag/AgCl electrode as reference electrode and a platinum sheet as counter-electrode in deaired solution with N2 using a potentiostat PGSTAT 302 with FRA module (Metrohm – AUTOLAB). The charge/discharge (CD) tests are obtained by applying constant current I of ±1.0, 0.75 and 0.5 mA (Ecut-off from -0.1 to 0.78 V vs. Ag/AgCl). Cyclic voltammograms (CV) are recorded in previously defined potential at sweep rate range from 10, 25, 50, 75 and 100 mV s−1. The electrochemical impedance spectroscopy (EIS) measurements are performed at open circuit potential (OCP) with ± 10 mV of the potential amplitude in the frequency range from10-3 to 105 Hz in 1.0 mol L-1 H2SO4.As can be seen, the FFC 2000 2:1 sample with 1350 seconds of synthesis presents higher specific capacitance as well as higher coulombic efficiency compared to FFC 2000 1:1 sample also with 1350 seconds of synthesis, with values at around 80 F/g and 90% respectively. On the other hand, the CFF 1000 1:1 sample with 1350 seconds of synthesis present higher values (33 F/g and 100%) than the sample CFF 1000 2:1 with 1350 seconds of synthesis (26 F/g and 100%). In addition, the increase in the intensity of the Faradaic peaks that were provided by the greater presence of the monomer synthesized on the surface of the substrate. The analogous way the excess of monomer may favor the formation of polymer on polymer which will intensify, also the redox peaks and will also favor the formation of reticles providing that form para- (cross) bonds in addition to ortho- (linear) bonds. Therefore, it is suggested that in comparison to the FFC 2000 samples we have a greater favor of para- in the polymeric chains, for the FFC 1000 samples it is suggested that it has formed a greater number of ortho-type bonds, as can be seen in the FT-IR data. By FEG-SEM it is possible to verify that in CFF 2000 2:1 1350 seconds there is a smaller formation of the polymer film with agglomerates by the entire structure of the felt comparing with the microscopy of the sample CFF 2000 1:1 1350 seconds. Also, a smaller surface area and/or a smaller amount of pores available as noted in the N2 adsorption isotherm but it is similarly observed that polymer chains in overlapping layers, which also suggests the formation of para- providing lower values of specific capacitance and coulombic efficiency. Note that the N2 adsorption isotherm suggests that the CFF 2000 1:1 sample has greater surface area and/or greater amount of pores available on its surface compared to fiber under the same conditions, which contribute to the greater accumulation of charge and coloumbic efficiency on storage devices.

Synthesis, characterization, and application of metal-free sulfonamide-vitamin C adduct to improve the optical properties of PVA polymer

Improving optical properties is an important topic in the field of polymer science. In this research, a novel, metal-free, and inexpensive vitamin C sulfonamide adduct has been developed to enhance the optical behaviors of polyvinyl alcohol (PVA). Initially, the vitamin C adduct has been fabricated through atom economic reaction and then characterized using several spectroscopic techniques, including 1 H NMR, 13 C NMR, DEPT-135, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Accordingly, a dramatic chemical alteration in ascorbic acid structure has been confirmed and led to enhancing chemical interactions with the host polymer. The ascorbic acid adduct has been doped into PVA to prepare a flexible film of polymer composites with potential optical behaviors. The identity of composite film has specified from FTIR, XRD, and UV–vis spectroscopy. The XRD pattern of the hybrid polymer has revealed a remarkable boost in its amorphous structure compared to the PVA host. The FTIR data of both matrix PVA and its composites reveal the potent chemical interactions of functional groups within the hybrid PVA. The main optical information of synthesized hybrid film was obtained from the UV–vis spectra. The refractive index ( n ) and dielectric loss ( ε i ) values are elevated notably, whereas the optical band gap energy (E g ) declined from 6.3 to 3.6 eV. The direct electronic transition between the valence band (VB) and conduction band (CB) was determined by implementing Tauc’s model. These preliminary results suggest that the fabricated flexible composite will have an excellent opportunity to use in the manufacturing optical devices.

Micro-tomographic and infrared spectral data mining for breast cancer diagnosis

This study aimed to introduce a multidimensional data mining method of breast cancer (BC) diagnosis using the X-ray phase-sensitive microtomography (XPCT) and Fourier transform infrared spectroscopy (FTIR), which is a comparable approach to clinical histopathologic examination (H&E) and blood biochemical tests for achieving a simple in-situ quantitative diagnosis. Based on the high brilliance synchrotron radiation, nondestructive three-dimensional (3D) micro-tomograms of tissues and infrared absorption spectra and mapping of representative biomacromolecules of tissue and blood samples were obtained with higher signal to noise ratios (SNRs). The comparative analysis had been made between in-situ digital sections and stained histological sections. The XPCT images accurately visualized the micromorphology of tumor lesions, including fat granule degenerations, ductal proliferations, microcalcifications, collagen strands of dimensions less than 20 µm. The FTIR mapping and spectra effectively revealed the biological component distributions and tumor-related variations of lipids, proteins and nucleic acids between breast tumors and normal tissues, integrated with XPCT data into formation of complementary data. It enables to identify the complex biomolecular tumor markers, especially, the specific fine-structures of second derivative spectrum were found in 1400–1750 cm−1. Moreover, the attenuated total reflection FTIR (ATR-FTIR) data of fresh blood samples were collected to demonstrate spectral specificity and feasibility of machine learning (ML) classification for BC diagnosis compared to clinic blood biochemical tests. The random forest (RF) model was found to be the best model for differentiating BC with 100% accuracy. Therefore, the proposed methodology was proved to be a powerful tool to nondestructively visualize and classify soft tissue tumors.