Fourier Transform Infrared Spectroscopy With Attenuated Total Reflectance Research Articles

β-Cyclodextrin-Modified Cotton Fabric for Medical and Hospital Applications with Photodynamic Antibacterial Activity Using Methylene Blue

The use of cyclodextrins in textiles for the development of biofunctional fabrics represents an interesting alternative for the advancement of dental, medical, and hospital materials. Cyclodextrins can interact with the chemical groups present in cotton fibers, leading to the formation of a nanostructured surface with specific functional properties, including antibacterial activity. Although there are numerous antibacterial textile finishes, the use of methylene blue as a cyclodextrin host molecule for photodynamic applications in textile materials remains to be investigated. This is because methylene blue is a photosensitive dye capable of generating singlet oxygen (1O2) when illuminated, which inactivates the pathogenic microorganisms that may be present in wounds. The objective of this study was to develop a biofunctionalized and photoactivatable cotton fabric with antimicrobial properties for use in the cosmetic or medical industries. The materials obtained were characterized via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), the determination of cotton fabric functionalization dyeing variables, colorimetry, UV-VIS spectrophotometry, degradation of 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA), photodegradation tests, and microbiological analysis. The results showed that the textile was functionalized with β-cyclodextrin, mainly evidenced by the appearance of the band at 1730 cm−1, indicating the formation of the ester group. Thus, when exposed to light, the non-functionalized material showed greater photobleaching, about 60%, compared to the material treated with cyclodextrin. This result was also reflected in the ABDA degradation kinetics, with the treated material showing 592.00% (first phase) and 966.20% (second phase) higher degradation than the untreated sample. Finally, the photodynamic activity was determined based on the antimicrobial properties of the textile, showing a reduction of more than 99% without exposure to light and 100% when exposed to light. It is believed that this study could open avenues for future research and the development of antimicrobial fabrics, as well as demonstrate the efficiency of the treatment with cyclodextrin in relation to photobleaching.

Contamination by microplastics and sorbed organic pollutants in the surface waters of the Tietê River, São Paulo-SP, Brazil

Microplastics (MPs) are particles between 1 μm and 5 mm in size, originating mainly from poor solid waste and effluent management, that can reach water bodies from various sources. In freshwater environments, the occurrence, distribution, and characterization of this new class of pollutants are still little explored, especially in Brazil. The aim of this study was to assess the occurrence of MPs, as well as the presence and concentration of polychlorinated biphenyls (PCBs) sorbed to these particles in the surface waters of the Tietê River - SP. Surface water samples were collected in duplicate during the dry and wet seasons. The identification and characterization of the MPs was carried out through visual inspection and the chemical identity of the particles was verified using Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). For the analysis of PCBs adsorbed to the MPs, the sample extracts were analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The MPs were found in concentrations ranging from 6.67 to 1530 particles m−3, with a predominance of the polymers polyethylene (PE, with 58.17 %) and polypropylene (PP, with 23.53 %). The main morphological categories identified were fragments (56.63 %), fibers (28.42 %), and transparent films (13.06 %). Higher abundances of PCBs were observed in the lower size range, between 0.106 and 0.35 mm. The total concentrations of PCBs in MPs ranged from 20.53 to 133.12 ng g−1. The results obtained here are relevant for understanding the dynamics and level of contamination of MPs and organic pollutants sorbed to these particles in the Tietê River, as well as helping with mitigation measures for the restoration and preservation of this ecosystem.

Sustainable starch-based bioplastics reinforced with carob filler: characterization and biodegradability assessments

Starch-based thermoplastic polymer is a biopolymer that is being widely explored as a replacement for conventional polymers. Since thermoplastic starch suffers from mechanical defects, certain mechanical and thermal properties of starch-based polymers can be improved by incorporating fillers or reinforcements derived mainly from natural substances. This article reports the preparation, physicochemical, and mechanical characterization and biodegradation of starch-based bioplastics extracted from potato (Solanum tuberosum) peels using glycerol (G) as plasticizer and reinforced with carob powder, a readily growing plant in Mediterranean climates. The present study investigates the effect of incorporating different proportions (0, 2, 5, 10, and 15 wt.%) of carob powder (Cb) in the films thus prepared. These biopolymer films were fully characterized using analytical techniques including Fourier transform infrared spectroscopy with attenuated total reflection (FTIR/ATR), thermogravimetric analysis (TGA/DTG), X-ray diffraction (XRD), optical microscopy (OM), Scanning electron microscopy (SEM), mechanical evaluations, and biodegradability assessments. The biodegradability of the obtained bioplastic samples was evaluated. Scanning electron microscopy (SEM) revealed strong interfacial adhesion between the constituent filler and the polymer matrix.

Analysis of the Impact of Waste Fly Ash on Changes in the Structure and Thermal Properties of the Produced Recycled Materials Based on Polyethylene.

This paper presents the results of the research on the structure and thermal properties of materials made from fly ash based on high-density polyethylene (HDPE). Composites based on a polyethylene matrix with 5, 10, and 15 wt% fly ash from hard coal combustion content were examined. Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) was used to identify characteristic functional groups present in the chemical structure of polyethylene and the composites based on its matrix. Structural analysis was performed using X-ray diffraction (XRD), a differential scanning calorimeter (DSC), and microscopic examinations. Mechanical properties were also examined. Analysis of the thermal effect values determined by the DSC technique, XRD, and FTIR-ATR allowed the evaluation of the crystallinity of the tested materials. Polyethylene is generally considered to be a two-phase system consisting of crystalline and amorphous regions and is a plastic characterized by a significant crystalline phase content. Based on the FTIR-ATR spectra, DSC curves, and XRD, the effect of the filler and the changes occurring in the materials studied resulted in a decrease in the degree of crystallinity and a change in the melting point and crystallization temperature of the polymer matrix were established. Microscopic examinations were carried out to analyze the microstructure of the composites to collect information on the distribution and shape of the filler particles, indicating their size and distribution in the polymer matrix. Furthermore, the use of scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDS) allowed for the microanalysis of the chemical composition of the filler particles.

Mattel's ©Barbie: Preventing Plasticizers Leakage in PVC Artworks and Design Objects through Film-Forming Solutions.

The main conservation problem of p-PVC artworks is phthalate-based plasticizer migration. Phthalate migration from the bulk to the surface of the materials leads to the formation of a glossy and oily film on the outer layers, ultimately reducing the flexibility of the material. This study aimed to develop a removable coating for the preservation of contemporary artworks and design objects made of plasticized polyvinyl chloride (p-PVC). Several coatings incorporating chitosan, collagen, and cellulose ethers were assessed as potential barriers to inhibiting plasticizer migration. Analytical techniques including optical microscopy (OM), ultraviolet/visible/near-infrared spectroscopy (UV/Vis/NIR), Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), and scanning electron microscopy (SEM) were utilized to evaluate the optical and chemical stability of selected coating formulations applied to laboratory p-PVC sheet specimens. Subsequently, formulations were tested on a real tangible example of a design object, ©Barbie doll, characterized by the prevalent issue of plasticizer migration. Furthermore, the results obtained with the tested formulations were evaluated by a group of conservators using a tailored survey. Finally, a suitable coating formulation capable of safeguarding plastic substrates was suggested.

Recovery of Proteases and Protease Inhibitors from Ganoderma spp. Cultivated in Amazonian Lignocellulose Wastes.

Ganoderma spp. are a great source of bioactive molecules. The production and recovery of bioactive molecules vary according to strain, growth substrate, and extraction solution. Variations in protease and their inhibitors in basidiomata from a commercial strain (G. lingzhi) and an Amazonian isolate (Ganoderma sp.) cultivated in Amazonian lignocellulosic wastes and extracted with different solutions are plausible and were investigated in our study. Basidiomata from cultivation in substrates based on açaí seed, guaruba-cedro sawdust and three lots of marupá sawdust were submitted to extraction in water, Tris-HCl, and sodium phosphate. Protein content, proteases, and protease inhibitors were estimated through different assays. The samples were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). Tris-HCl provided higher protein extraction from Ganoderma sp. and higher caseinolytic, gelatinolytic, and fibrinolytic activity for G. lingzhi cultivated in açaí. Water extracts of Ganoderma sp., in general, exhibited higher trypsin and papain inhibitor activities compared to G. lingzhi. Extracts in Tris-HCl and sodium phosphate showed more intense protein bands in SDS-- PAGE, highlighting bands of molecular weights around 100, 50, and 30 kDa. FTIR spectra showed patterns for proteins in all extracts, with variation in transmittance according to substrate and extractor. Water extract from Amazonian Ganoderma sp. cultivated in marupá wastes are promising as a source of protease inhibitors, while the Tris-HCL extract of G. lingzhi from açaí cultivation stands out as a source of proteases with fibrinolytic, caseinolytic, and gelatinolytic activities.

Enhancing Liquefaction Efficiency: Exploring the Impact of Pre-Hydrolysis on Hazelnut Shell (Corylus avellana L.).

Hazelnut shells (HS), scientifically known as Corylus avellana L. shells, are waste produced by companies that process nuts. The main objective of this study was to find an efficient way to maximize the chemical potential of HS by solubilizing the hemicelluloses, which could then be used to recover sugars and, at the same time, increase the lignin content of this material to produce adhesives or high-strength foams. In order to optimize the pre-hydrolysis process, two different temperatures (160 and 170 °C) and times varying from 15 to 180 min were tested. All the remaining solid materials were then liquefied using polyalcohols with acid catalysis. The chemical composition of hazelnut shells was determined before and after the pre-hydrolysis. All of the process was monitored using Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) by determining the spectra of solids and liquids after the pre-hydrolysis and liquefaction steps. The highest solubilization of hazelnut shells was found for 170 °C and 180 min, resulting in a 25.8% solubilization. Chemical analysis after the hydrolysis process showed a gradual increase in the solubilization of hemicelluloses as both the temperature and time of the reactor were increased. Simultaneously, the percentages of α-cellulose and lignin in the material also increased with rises in temperature and duration. FTIR-ATR allowed for the detection of significant spectral changes in the hazelnut shells from their initial state to the solid residue and further into the liquefied phase. This confirmed that pre-hydrolysis was effective in enhancing the chemical composition of the material, making it more suitable for the production of adhesives, polyurethane foams, or in the production of bioplastics and composite materials, combined with other biopolymers or synthetic polymers to enhance the mechanical properties and biodegradability of the resulting materials.

Experimental evaluation of atmospheric plasma treatment effects on different textures of CFRP composite for aircraft applications

This article examines the impact of Atmospheric Plasma Treatment (APL) on the chemical composition and fracture properties of various textured surfaces (tool and bag side) of carbon fiber/epoxy (CFRP) composites utilized in aircraft applications. For this purpose, parameters of atmospheric plasma (APL) surface treatment were evaluated in comparison to chemical cleaning and peel-ply applications, taking into account its effects on surface properties and adhesive bond strength. A comprehensive variety of surface characterization techniques were utilized to analyze surface modifications, including water and diiodomethane contact angle measurements for assessing surface hydrophilicity, Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR) and X-ray Photoelectron Spectroscopy (XPS) for analyzing chemical composition and functional groups, and Profilometry, Atomic Force Microscopy (AFM), and Scanning Electron Microscopy (SEM) for evaluating surface topography and morphology. Experimental results indicated that the reduction in the contact angle following plasma treatment correlated with the elevated oxygen concentration and the presence of polar functional groups (e.g. -OH, -NH2, -NH3, C=O, O-C=O) on the composite surface. Plasma treatment, especially at low nozzle speeds, increased surface roughness on the bag side surfaces. This prevented adhesive penetration and led to gas entrapment, resulting in adhesive failure mode and reduced single lap shear strength for the bag side. In contrast, on the tool side surfaces, the plasma treatment led to a remarkable 19.7% enhancement in shear strength, highlighting its effectiveness.

The Possible Use of Stable Carbon and Nitrogen Isotope Signal and Spectral Analysis to Identify Habitat Condition of Aquatic Plants

Many macrophyte species exhibit a high degree of plasticity, enabling them to thrive in various aquatic ecosystems. Identifying the growth conditions of individual aquatic plant species during research or specimen collection is not always possible. In many cases, the nature of the planned research does not necessitate recognizing environmental conditions. However, the scope of identifying the habitat parameters of the collections of submerged aquatic plant herbariums provides an opportunity for further research. This paper explores the possibilities of using isotopic signals of plants, supported by spectral analyses of powdered plant materials, to ascertain the environmental conditions from which the samples were collected. The results obtained from the stable carbon and nitrogen isotope compositions (δ13CORG and δ15NORG) and the analysis of spectral spectra via FTIR-ART (Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance) of plant material (Elodea canadensis Michx. species) collected from various habitat ecosystems, including rivers and both hard- and softwater lakes, exhibited significant distinctions between these habitats. Particularly high values of δ15NORG were recorded in the material from rivers. The stable carbon and nitrogen isotope compositions did not differentiate between the material collected from softwater and hardwater lakes. Nevertheless, when comparing the isotopic findings with the FTIR-ATR spectral analysis focused on identifying characteristic peaks associated with the presence of calcium carbonate, noticeable differences were observed in the presence and intensity of calcium carbonate peaks in the material. These differences were only evident when nondecarbonated plant material from hardwater lakes was used for the FTIR-ATR analysis. To the best of the author’s knowledge, the combination of methods applied in this study to identify the origin of E. canadensis from various freshwater environments is the first application of its kind that could enable the rapid identification of plant material origin. Such identification could prove useful in environmental, ecological, and paleoenvironmental research. The increased knowledge of macrophytes’ δ13CORG and δ15NORG values might also be essential in further tracking accelerated eutrophication based on aquatic vegetation’s isotopic signals. This might be important due to the assumption that the increased rate of eutrophication influences organic matter sedimentation in aquatic ecosystems, especially lakes.

Non-Aqueous Poly(dimethylsiloxane) Organogel Sponges for Controlled Solvent Release: Synthesis, Characterization, and Application in the Cleaning of Artworks.

Polydimethylsiloxane (PDMS) organogel sponges were prepared and studied in order to understand the role of pore size in an elastomeric network on the ability to uptake and release organic solvents. PDMS organogel sponges have been produced according to sugar leaching techniques by adding two sugar templates of different forms and grain sizes (a sugar cube template and a powdered sugar template), in order to obtain materials differing in porosity, pore size distribution, and solvent absorption and liquid retention capability. These materials were compared to PDMS organogel slabs that do not contain pores. The sponges were characterized by Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and compared with PDMS slabs that do not contain pores. Scanning electron microscopy (SEM) provided information about their morphology. X-ray micro-tomography (XMT) allowed us to ascertain how the form of the sugar templating agent influences the porosity of the systems: when templated with sugar cubes, the porosity was 77% and the mean size of the pores was ca. 300 μm; when templated with powdered sugar, the porosity decreased to ca. 10% and the mean pore size was reduced to ca. 75 μm. These materials, porous organic polymers (POPs), can absorb many solvents in different proportions as a function of their polarity. Absorption capacity, as measured by swelling with eight solvents covering a wide range of polarities, was investigated. Rheology data established that solvent absorption did not have an appreciable impact on the gel-like properties of the sponges, suggesting their potential for applications in cultural heritage conservation. Application tests were conducted on the surfaces of two different lab mock-ups that simulate real painted works of art. They demonstrated further that PDMS sponges are a potential innovative support for controlled and selective cleaning of works of art surfaces.

Eco‐friendly biodiesel production using passion fruit peels and cupuaçu seeds: Catalyst development and process optimization

AbstractYellow passion fruit peel and cupuaçu seeds are common wastes. Usually, they have few or no applications and are discarded, causing environmental pollution. To use them in a new way and reduce ecological pollution, we obtained the ash of yellow passion fruit peels by calcination. We characterized it using Fourier‐transform infrared spectroscopy with attenuated total reflectance (FTIR‐ATR), X‐ray fluorescence (XRF), X‐ray diffractometry (XRD), adsorption‐desorption of N2, scanning electron microscopy (SEM), basicity, and soluble alkalinity. It was observed that the ash was mainly composed of potassium (69%) in the form of carbonate, chloride, and sulfate, with a good surface area (11.23 m2 g−1). The cupuaçu butter was also extracted from the cupuaçu seeds and characterized, showing low acidity, peroxide, saponification, and iodine indexes, in addition to presenting a lipid profile with 57% saturated fatty acid and 43% unsaturated fatty acid. Oleic and stearic acids were present in higher proportions. These results demonstrate that this butter can be a sustainable input in biodiesel production. Thus, the ash was used as a heterogeneous catalyst in the butter transesterification. The biodiesel synthesis was optimized, resulting in 97.8% butter conversion into biodiesel under the following conditions: reaction time of 2 h, 5 wt% of catalyst, 80 °C, and a methanol‐to‐oil molar ratio of 30. This work, therefore, shows that it is possible to obtain and utilize bioinputs, such as cupuaçu butter and passion fruit peel ash, to produce biodiesel through transesterification, and the use of waste materials (precisely passion fruit peels and cupuaçu seeds) makes this method a cost‐effective and environmentally friendly approach to biofuel production.

Influence Analysis of Polyvinyl Alcohol on the Degradation of Artificial Leather with Cellulose Nitrate Coating Originating from a Suitcase Stored in the Collection of the Auschwitz-Birkenau State Museum in Oświęcim, Poland.

The aim of this study was to assess the influence of a protective layer of polyvinyl alcohol on the degradation process of artificial leather based on cellulose nitrate. Samples of the artificial leather were obtained from a suitcase dating back to the first half of the 20th century, not considered a historical artifact. The analysis involved Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS). Artificial aging was employed for the study. The artificial leather sample with a protective coating of polyvinyl alcohol on a cellulose nitrate base exhibited the lowest degree of degradation due to minimal chemical changes in cellulose esters. The obtained FTIR-ATR spectrum indicated significantly higher nitration of cellulose and, consequently, a lower degree of polymer degradation. The sample without the protective polyvinyl alcohol coating and the sample with the coating removed before artificial aging showed similar reactions.

Influence of Silver Nanoparticles on Color Stability of Room-Temperature-Vulcanizing Maxillofacial Silicone Subjected to Accelerated Artificial Aging

In this in vitro study, we assessed the color stability of an A-2186 room-temperature-vulcanizing (RTV) silicone elastomer by incorporating silver nanoparticles during accelerated artificial aging. Using five intrinsic silicone pigment types, including no pigment (colorless), red, blue, mocha, and a combination of the three, we created 160 disk-shaped specimens. These were evenly distributed across 20 experimental groups, each containing 8 samples (n = 8). The specimens underwent aging for 250 and 500 h in an artificial aging chamber. A colorimeter was used to measure the values of L*a*b* according to the Commission Internationale de L’Éclairage (CIE) standards. The 50:50% perceptibility threshold (∆E* = 1.1) and acceptability threshold (∆E* = 3.0) were used in the interpretation of the recorded color differences. At the 0.05 level of significance, the one-way analysis of variance (ANOVA) and Tukey post hoc test were used in the statistical analysis. Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) showed that 0.2% AgNPs after 500 h of aging protected the silicone elastomer matrix and all characteristic bonds of the silicone elastomer. In contrast, silicone without AgNPs showed the distortion of all bonds after 500 h. Chromatic alterations (∆E* > 0) were observed in all specimen groups, surpassing the perceptible threshold (1.1 units), except for mocha, with 0.2% AgNPs after 250 h of aging, which remained below the perceptible threshold (∆E* = 0.97). All groups demonstrated ∆E* values below the acceptable threshold, except for the red color, which exhibited a highly significant color change (p = 0.000). This study determined that all specimens, including colorless silicone, underwent color changes (∆E* > 0), with red displaying a notably significant chromatic alteration. Additionally, AgNPs demonstrated substantial protection of the silicone and reduced the color change across all groups and colors, with enhanced efficacy corresponding to higher AgNP concentrations (0.2% AgNPs > 0.15% AgNPs > 0.1% AgNPs).

Determination of key factors affecting biofilm formation on the aged Poly(ethylene terephthalate) during anaerobic digestion

Biofilm formation on plastic surface is a growing concern because it can alter the plastic surface properties and exacerbate the ecological risk. Identifying key factors that affecting biofilm formation is critical for effective pollution control. In this study, the poly (ethylene terephthalate) (PET) was aged in water and air conditions with UV irradiation, then incubated in the digestate of food waste anaerobic digestion to allow biofilm formation. Surface analysis techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), were utilized to investigated the changes in the topography, roughness, hydrophily, and functional groups change of the PET surface during the aging process. Confocal laser scanning microscopy (CLSM) was used to determine the distribution of microorganisms on the PET surface after incubation in the digestate. This study focused on understanding the interactions between the PET surface and biofilm to identify critical surface factors that affect biofilm formation. Results showed that the four months aging process decreased the contact angle of the PET surface from 96.92° to 76.08° and 68.97° in water and air conditions, respectively, corresponding to an increase of 44% and 70% in the surface energy. Additionally, aging in air conditions led to a rougher surface compared to water conditions. The arithmetic roughness average (Ra) of the PET-Water was 11.0 nm, comparable to that of the pristine PET, while the value of PET-Air was much higher (43.9 nm). The results further indicated that biofilm formation during anaerobic digestion was more sensitive to roughness than hydrophily. The PET surface aged in air conditions provided a more suitable environment for microbial reproduction, leading to the aggradation of living cells.

Self-assembled lyotropic liquid crystals gel systems for retinol protection and octyl methoxycinnamate skin delivery

Lyotropic liquid crystals (LLCs) gel were prepared in aqueous solutions from sodium dodecyl and tetradecyl glycoside sulfate (APGS-Na) and the mixture of oleic acid with polyethylene glycol 400 (OP) to encapsulate retinol and octyl methoxycinnamate (OMC) as the medication delivery barrier. Complementary analysis like polarized optical microscopy (POM), small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), and rheology were applied to characterize the LLCs gel. Additionally, the rate of retinol degradation in various retinol-loaded LLCs gel systems as well as the in vitro skin penetration and retention capabilities of OMC-loaded LLCs gel systems were assessed. According to the findings, the inner structure of the systems was lamellar (Lα) mesophase, which would be affected by the change of OP ratios. In addition, retinol-loaded LLCs gel decreased its degradation rate, while OMC-loaded sample presented the higher stratum corneum (SC) retention and lower epidermis and dermis (E + D) retention. Collectively, this study provides an effective way to prevent retinol from degradation as well as to control the release of OMC from LLCs.

Degradation of polypropylene by fungi Coniochaeta hoffmannii and Pleurostoma richardsiae

The urgent need for better disposal and recycling of plastics has motivated a search for microbes with the ability to degrade synthetic polymers. While microbes capable of metabolizing polyurethane and polyethylene terephthalate have been discovered and even leveraged in enzymatic recycling approaches, microbial degradation of additive-free polypropylene (PP) remains elusive. Here we report the isolation and characterization of two fungal strains with the potential to degrade pure PP. Twenty-seven fungal strains, many isolated from hydrocarbon contaminated sites, were screened for degradation of commercially used textile plastic. Of the candidate strains, two identified as Coniochaeta hoffmannii and Pleurostoma richardsiae were found to colonize the plastic fibers using scanning electron microscopy (SEM). Further experiments probing degradation of pure PP films were performed using C. hoffmannii and P. richardsiae and analyzed using SEM, Raman spectroscopy and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The results showed that the selected fungi were active against pure PP, with distinct differences in the bonds targeted and the degree to which each was altered. Whole genome and transcriptome sequencing was conducted for both strains and the abundance of carbohydrate active enzymes, GC content, and codon usage bias were analyzed in predicted proteomes for each. Enzymatic assays were conducted to assess each strain’s ability to degrade naturally occurring compounds as well as synthetic polymers. These investigations revealed potential adaptations to hydrocarbon-rich environments and provide a foundation for further investigation of PP degrading activity in C. hoffmannii and P. richardsiae.

Hot Melt Extrusion as an Effective Process in the Development of Mucoadhesive Tablets Containing Scutellariae baicalensis radix Extract and Chitosan Dedicated to the Treatment of Oral Infections

Hot Melt Extrusion (HME) technology was developed to obtain blends containing lyophilized Scutellariae baicalensis root extract and chitosan in order to improve the rheological properties of the obtained blends, including tableting and compressibility properties. (Hydroxypropyl)methyl cellulose (HPMC) in 3 different ratios was used as amorphous matrix formers. The systems were characterized using X-ray powder diffraction (PXRD), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR), and in vitro release, permeability, and microbiological activity studies. Then, the extrudates were used to prepare tablets in order to give them the appropriate pharmaceutical form. HPMC-based systems released baicalin more slowly, resulting in delayed peaks in the acceptor fluid. This behavior can be explained by the fact that HPMC swells significantly, and the dissolved substance must have diffused through the polymer network before being released. The best tabletability properties are provided by the formulation containing the extrudate with lyophilized extract HPMC 50:50 w/w. These tablets offer a valuable baicalin release profile while maintaining good mucoadhesive properties that condition the tablet's retention in the application site and the effectiveness of therapy.

Characterization of the cross-lamellar structure of Olivancillaria urceus (Gastropoda: Olividae) and its dissolution pattern

In this work, we sought to characterize the cross-lamellar microstructure of the gastropod Olivancillaria urceus (Röding, 1798) and its profile after immersion in acid medium. For crystallographic analysis, segments of the valve were removed and crushed. The powder obtained was analyzed using Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) and X-ray Diffractometry (XRD) techniques. For microstructural analysis, eight sections were taken from the shell using a rotary saw. The face of interest of each section was polished with Saint Gobain silicon carbide abrasive powder with mesh sizes of 320, 500, 600, and 1000. The eight sections were divided into four groups of two samples. Three groups were left in 4 % glacial acetic acid solution diluted in water for intervals of 20, 40, and 60 min, respectively, and the control group was not degraded. All wafers were then analyzed in Scanning Electron Microscopy to ascertain the microstructure. The angle and thickness of the layers were determined by Image J software. As a result of the FTIR-ATR technique, a transmittance spectrum was obtained whose valleys represent the vibrational modes of the carbonate ion. The diffractogram peaks and their respective Miller indices, are characteristic of the aragonite crystallographic structure and a small fraction of calcite. The micrographs obtained exposed 3 layers of cross-lamellar microstructure, however, the third and innermost layer showed discontinuity. The angle and average thickness were (105 ± 2)° and (727 ± 5)µm for the outermost layer and (116 ± 3)° and (668 ± 6)µm for the middle layer. The tablets immersed in acid medium showed loss of orientation of the calcium carbonate grains after 40 min and 60 min. Thus, the O. urceus shell exhibits orthorhombic calcium carbonate crystallography. Three layers of cross-lamellar microstructure were identified, as well as the configuration of the structure after contact with corrosive media. These results contribute to the characterization of natural materials and serve as a basis for analysis of the preservation potential in the fossil record.

Development of Thin Films from Thermomechanical Pulp Nanofibers of Radiata Pine (Pinus radiata D. Don) for Applications in Bio-Based Nanocomposites

The main objective of this study was to develop cellulose nanofibers from the thermomechanical pulp (TMP) of Radiata Pine (Pinus radiata D. Don), and for this, a one-step micro-grinding process was used. The newly developed material was called thermomechanical pulp nanofibers (TMP-NF). In the first instance, a determination of the constituents of the TMP was carried out through a chemical characterization. Then, TMP-NFs were compared with cellulose nanofibers (CNF) by morphological analysis (Scanning Electron Microscopy, SEM, and Atomic Force Microscopy, AFM), X-ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR). In addition, films were developed from TMP-NF and CNF using a vacuum filtration manufacturing method. For this study, 0.10, 0.25, 0.50, and 1.00% dry weight of CNF and TMP-NF were used as continuous matrices without organic solvents. The films were characterized by determining their morphological, physical, surface properties, and mechanical properties. The main results showed that morphological analysis by SEM and AFM for the fractionated sample indicated a fiber diameter distribution in the range of 990-17 nm and an average length of 5.8 µm. XRD analysis showed a crystallinity index of 90.8% in the CNF, while in the TMP-NF, it was 71.2%, which was foreseeable. FTIR-ATR analysis showed the functional groups of lignin and hemicellulose present in the TMP-NF sample. The films presented apparent porosity values of 33.63 for 1.00% solids content of CNF and 33.27% for 0.25% solids content of TMP-NF. The contact angle was 61.50° for 0.50% solids content of CNF and 84.60° for 1.00% solids content of TMP-NF. Regarding the mechanical properties, the modulus of elasticity was 74.65 MPa for CNF and 36.17 MPa for TMP-NF, and the tensile strength was 1.07 MPa for CNF and 0.69 MPa for TMP-NF. Although the mechanical properties turned out to be higher in the CNF films, the TMP-NF films showed improved surface characteristics as to surface hydrophobic and apparent porosity. In addition, the easy and rapid obtaining of TMP nanofibers makes it a promising material that can be used in biologically based nanocomposites.

Ultrasound-assisted diffusion of waxy starch cryogel on frozen-stored pork meat

The development and application of new materials that allow the characteristics of the meat to be maintained as far as possible before freezing, minimizing the damage caused by the crystals formation, is something that has been studied over time because it is of great interest to meat industry. We worked with waxy starch cryogel of two cycles, applied with high-intensity ultrasound in pork meat. Their effect before and after freezing was evaluated by Modulated Differential Scanning Calorimetry (MDSC), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), Scanning Electron Microscopy (SEM), shear force, and color profiles. It was found that the cryogel generated important changes (P < 0.05) due to its interaction with the water and protein of the meat, decreasing the size of the spaces for ice crystal growth by approximately 75% compared to the control (meat without cryoprotectant). There were thermal, molecular, and structural changes (P < 0.05) that influenced some quality aspects such as pH, water activity, shear force, and color, avoiding important modifications because of the freezing-thawing process.