Advances in Regenerative and Reconstructive Medicine in the Prevention and Treatment of Bone Infections.

Reconstructive and regenerative medicine are critical disciplines dedicated to restoring tissues and organs affected by injury, disease, or congenital anomalies. These fields rely on biomaterials like synthetic polymers, metals, ceramics, and biological tissues to create substitutes that integrate seamlessly with the body. Personalized implants and prosthetics, designed using advanced imaging and computer-assisted techniques, ensure optimal functionality and fit. Regenerative medicine focuses on stimulating natural healing mechanisms through cellular therapies and biomaterial scaffolds, enhancing tissue regeneration. In bone repair, addressing defects requires advanced solutions such as bone grafts, essential in medical and dental practices worldwide. Bovine bone scaffolds offer advantages over autogenous grafts, reducing surgical risks and costs. Incorporating antimicrobial properties into bone substitutes, particularly with metals like zinc, copper, and silver, shows promise in preventing infections associated with graft procedures. Silver nanoparticles exhibit robust antimicrobial efficacy, while zinc nanoparticles aid in infection prevention and support bone healing; 3D printing technology facilitates the production of customized implants and scaffolds, revolutionizing treatment approaches across medical disciplines. In this review, we discuss the primary biomaterials and their association with antimicrobial agents.

Development of an Apple Snack Enriched with Probiotic Lacticaseibacillus rhamnosus: Evaluation of the Refractance Window Drying Process on Cell Viability.

The objective of this study was to develop a dried apple snack enriched with probiotics, evaluate its viability using Refractance Window (RWTM) drying, and compare it with conventional hot air drying (CD) and freeze-drying (FD). Apple slices were impregnated with Lacticaseibacillus rhamnosus and dried at 45 °C using RWTM and CD and FD. Total polyphenol content (TPC), color (∆E*), texture, and viable cell count were measured, and samples were stored for 28 days at 4 °C. Vacuum impregnation allowed for a probiotic inoculation of 8.53 log CFU/gdb. Retention values of 6.30, 6.67, and 7.20 log CFU/gdb were observed for CD, RWTM, and FD, respectively; the population in CD, RWTM remained while FD showed a decrease of one order of magnitude during storage. Comparing RWTM with FD, ∆E* was not significantly different (p < 0.05) and RWTM presented lower hardness values and higher crispness than FD, but the RWTM-dried apple slices had the highest TPC retention (41.3%). Microstructural analysis showed that RWTM produced a smoother surface, facilitating uniform moisture diffusion and lower mass transfer resistance. The effective moisture diffusion coefficient was higher in RWTM than in CD, resulting in shorter drying times. As a consequence, RWTM produced dried apple snacks enriched with probiotics, with color and TPC retention comparable to FD.

Novel protein stabilization in white wine: A study on thermally treated zirconia-alumina composites.

A major concern for wineries is haze formation in white wines due to protein instability. Despite its prevalent use, the conventional bentonite method has shortcomings, including potential alteration of color and aroma, slow processing times, and notable wine wastage. Zirconium oxide (ZrO2) effectively removes proteins without affecting wine characteristics. However, producing cost-effective ZrO2 materials with efficient protein removal capabilities poses a significant challenge. This research aims to assess the viability of designing a porous material impregnated with zirconia to remove turbidity-causing proteins effectively. For this purpose, the support material alone (Al2O3) and the zirconia-impregnated support (ZrO2/Al2O3) were subjected to different calcination temperatures. It was observed that high-temperature treatments (750 °C) enhanced wine stability and protein adsorption capacity. The optimal adsorbent achieved a notable reduction in turbidity, decreasing the ΔNTU from 42 to 18, alongside a significant 44 % reduction in the total protein content, particularly affecting proteins in the molecular weight range of 10 to 70 kDa. This result is attributed to modifying the textural properties of ZrO2/Al2O3, characterized by the reduction of acidic sites, augmented pore diameters from 4.81 to 7.74 nm, and the emergence of zirconia clusters across the surface of the porous support. In summary, this study presents the first application of zirconia on the alumina support surface for protein stabilization in white wine. Combining ZrO2/Al2O3 and a high-temperature treatment emerges as a promising, cost-efficient, and environmentally sustainable strategy for protein removal in white wine.

Low viscosity silicone with less shrinkage for brain slices.

Plastination consists of replacing lipid and water with a curable polymer. This technique has numerous advantages, of which the production of non-toxic, inert, highly durable, dry, and easy maintenance and storage specimens stand out. Like all anatomical techniques, plastination also has disadvantages, and one of them is tissue shrinkage. The feasibility of using low viscosity domestic silicone (0,1Pa.s at 20°C) to plastinate brain slices was examined. Twenty humans, 10 millimeters (mm) brain slices were impregnated, ten slices each with two polymers [10 with domestic low viscosity polymer - P1 and 10 slices with Biodur® (0,45-0,6Pa.s at 20°C) S10]. Shrinkage was accessed by volume and area measurements. Volume shrinkage was significantly less in the slices impregnated with low viscosity domestic polymer, demonstrating the feasibility to plastinate brain slices with domestic low viscosity silicone polymer.

Fabrication of polycaprolactone/calcium phosphates hybrid scaffolds impregnated with plant extracts using 3D printing for potential bone regeneration.

The increase in critical bone diseases and defects in the world's population increases the need for bone substitutes to restore form and function. Organic and inorganic scaffolds with antibacterial properties could provide advantages for bone regeneration. In this study, we obtained scaffolds of polycaprolactone (PCL) charged with calcium phosphates nanoparticles and impregnated with extracts of Colombian plants as an alternative for potential bone regeneration. Calcium phosphate nanoparticles were obtained via auto-combustion synthesis. The nanoparticles were incorporated into the PCL with a chemical dissolution-disperse process. The composite obtained was used to produce a filament to print Triply Periodic Minimal Surface (TPMS) based scaffolds. Such geometry facilitates cellular growth thanks to its interconnected porosity. The scaffolds were impregnated with extracts of Justicia cf colorifera (Acanthaceae), and Billia rosea (Sapindaceae) due to their ancestral medical applications. A physical and biological characterization was conducted. The process to print scaffolds with an enhanced geometry to facilitate the flux of biological fluids was successful. The scaffolds loaded with B. rosea showed strong antibacterial behavior, suggesting the presence of reported terpenoids with antibacterial properties. The approach used in this study evidenced promising prospects for bone defect repair.

Porous Microparticles of Corn Starch as Bio-Carriers for Chia Oil.

Native corn starch and pretreated corn starch were treated with α-amylase, glucoamylase and mixtures of both to generate starches with high porosity with conserved granular structure. Porous starches were characterized; particle size distribution analysis, nitrogen adsorption-desorption analysis, scanning electron microscopy, water and oil adsorption capacity, differential scanning calorimeter, X-ray diffraction and damaged starch techniques were used. The α-amylase/glucoamylase mixture at the highest dose was the best treatment to generate porous starches with interesting adsorption capacity and granular structure conservation. Selected starches were impregnated with chia oil using a vacuum. Pretreated corn starch modified with the α-amylase/glucoamylase mixture showed no significant differences on impregnation capacity compared with native starch with a similar enzyme treatment. The highest oxidative stability was achieved with pretreated porous starch impregnated with 10 to 25% chia oil, compared with the bulk oil (5.37 to 4.72 and 2.58 h, respectively). Results have demonstrated that vacuum impregnation could be a potential technique for the incorporation of oil in porous structures based on starch and porous starches obtained by enzymatic hydrolysis are a promising material for the incorporation and protection of oils susceptible to oxidation.

Electrochemical and Electroconductive Behavior of Silk Fibroin Electrospun Membrane Coated with Gold or Silver Nanoparticles.

The surface modification of materials obtained from natural polymers, such as silk fibroin with metal nanoparticles that exhibit intrinsic electrical characteristics, allows the obtaining of biocomposite materials capable of favoring the propagation and conduction of electrical impulses, acting as communicating structures in electrically isolated areas. On that basis, this investigation determined the electrochemical and electroconductive behavior through electrochemical impedance spectroscopy of a silk fibroin electrospun membrane from silk fibrous waste functionalized with gold or silver nanoparticles synthetized by green chemical reduction methodologies. Based on the results obtained, we found that silk fibroin from silk fibrous waste (SFw) favored the formation of gold (AuNPs-SFw) and silver (AgNPs-SFw) nanoparticles, acting as a reducing agent and surfactant, forming a micellar structure around the individual nanoparticle. Moreover, different electrospinning conditions influenced the morphological properties of the fibers, in the presence or absence of beads and the amount of sample collected. Furthermore, treated SFw electrospun membranes, functionalized with AuNPs-SFw or AgNPS-SFw, allowed the conduction of electrical stimuli, acting as stimulators and modulators of electric current.

Reaching Visible Light Photocatalysts with Pt Nanoparticles Supported in TiO2-CeO2.

Nanostructured catalysts of platinum (Pt) supported on commercial TiO2, as well as TiO2-CeO2 (1, 5 and 10 wt% CeO2), were synthesized through the Sol-Gel and impregnation method doped to 1 wt% of Platinum, in order to obtain a viable photocatalytic material able to oxidate organic pollutants under the visible light spectrum. The materials were characterized by different spectroscopy and surface techniques such as Specific surface area (BET), X-ray photoelectron spectroscopy (XPS), XRD, and TEM. The results showed an increase in the diameter of the pore as well as the superficial area of the supports as a function of the CeO2 content. TEM images showed Pt nanoparticles ranking from 2-7 nm, a decrease in the particle size due to the increase of CeO2. The XPS showed oxidized Pt2+ and reduced Pt0 species; also, the relative abundance of the elements Ce3+/Ce4- and Ti4+ on the catalysts. Additionally, a shift in the Eg band gap energy (3.02-2.82 eV) was observed by UV-vis, proving the facticity of applying these materials in a photocatalytic reaction using visible light. Finally, all the synthesized materials were tested on their photocatalytic oxidation activity on a herbicide used worldwide; 2,4-Dichlorophenoxyacetic acid, frequently use in the agriculture in the state of Jalisco. The kinetics activity of each material was measured during 6 h of reaction at UV-Vis 190-400 nm, reaching a removal efficiency of 98% of the initial concentration of the pollutant in 6 h, compared to 32% using unmodified TiO2 in 6 h.

Simple Preparation of Metal-Impregnated FDM 3D-Printed Structures.

Modifying the natural characteristics of PLA 3D-printed models is of interest in various research areas in which 3D-printing is applied. Thus, in this study, we describe the simple impregnation of FDM 3D-printed PLA samples with well-defined silver nanoparticles and an iron metal salt. Quasi-spherical and dodecahedra silver particles were strongly attached at the channels of 3D-printed milli-fluidic reactors to demonstrate their attachment and interaction with the flow, as an example. Furthermore, Fenton-like reactions were successfully developed by an iron catalyst impregnated in 3D-printed stirrer caps to induce the degradation of a dye and showed excellent reproducibility.

Malachite Green Dye Decoloration over Au/TiO2-Nanotubes Photocatalyst under Simulate Visible-Light Irradiation.

Au nanoparticles were supported on TiO2 nanotubes by a novel vapor phase impregnation approach (VPI) using gold dimethyl-acetylacetonate as a precursor. This study aimed to evaluate the capacity of these materials in the photodecoloration of malachite green dye, with the vision to correlate the chemical, structural, morphological, and optical properties with its photocatalytic performance. The photocatalysts were characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectronic spectroscopy (XPS), electronic microscopy (HAADF-STEM and HRTEM), and UV-vis spectroscopy. The techniques mentioned above made it possible to detect the presence of small gold nanoparticles (around 3.1 nm), with a high apparent dispersion even at high metal loading for all analyzed systems. According to the XPS results, the Au nanoparticles remain reduced (Au°), and they have a high electronic interaction with TiO2, which eventually originates an electronic exchange between them and consequently a decrease in the band gap energy. In addition, the surface plasmonic resonance observed through UV-vis spectroscopy of the Au nanoparticles are factors that can be related to the high decoloration observed in these photocatalysts, specifically in the 15 wt% Au material, which achieves maximum photodecoloration of malachite green dye at 93%.

Convective drying of mango enriched with phenolic compounds from grape residue flour under different impregnation methods.

This work evaluated the effect of convective drying of mango impregnated with grape residue flour polyphenols under different vacuum impregnation methods with or without performing osmotic treatment and ultrasound on the global quality of dried mango in relation to chemical, microbiological and sensory aspects. Higher retention of carotenoids, phenolic compounds, and ascorbic acid was obtained with shorter drying times and lower oxygen exposure. Impregnated dried samples submitted to ultrasound-assisted vacuum impregnation showed a higher drying rate, greater retention of carotenoids (6.77 µg/g DM), and softer samples. Greater retention of phenolic compounds (1.84 mg GAE/g DM) was obtained for osmotic dehydration-assisted vacuum impregnation dried mango, while osmosonication-assisted impregnation was able to retain the highest ascorbic acid content (7.05 mg/100 g DM). Sensory evaluation showed that the impregnated samples showed good acceptance. The combination of osmotic dehydration and ultrasound could be a suitable way to produce dried mango impregnated with grape residue polyphenols.

Screening of the Supercritical Impregnation of Olea europaea Leaves Extract into Filaments of Thermoplastic Polyurethane (TPU) and Polylactic Acid (PLA) Intended for Biomedical Applications.

The leaves of Olea europaea as agricultural waste represent a convenient source of antioxidants. In combination with supercritical CO2 (scCO2), assisted impregnation is an interesting strategy for the preparation of biomedical devices with specific bioactivity. For this purpose, 3D-printable filaments of thermoplastic polyurethane (TPU) and polylactic acid (PLA) were employed for the supercritical impregnation of ethanolic olive leaves extract (OLE) for biomedical application. The extraction of OLE was performed using pressurized liquids. The effect of pressure (100-400 bar), temperature (35-55 °C), and the polymer type on the OLE impregnation and the swelling degree were studied including a morphological analysis and the measurement of the final antioxidant activity. All the studied variables as well as their interactions showed significant effects on the OLE loading. Higher temperatures favored the OLE loading while the pressure presented opposite effects at values higher than 250 bar. Thus, the highest OLE loadings were achieved at 250 bar and 55 °C for both polymers. However, TPU showed c.a. 4 times higher OLE loading and antioxidant activity in comparison with PLA at the optimal conditions. To the best of our knowledge, this is the first report using TPU for the supercritical impregnation of a natural extract with bioactivity.

Pathological Evaluation by Microtomography of Ranula. Clinical Case Report

ABSTRACT: This study aims to demonstrate, through a clinical case report, the applicability of the use of microtomography (µCT) in the histopathological evaluation of a ranula lesion on the oral floor and to evaluate the use of 2 % elemental iodine solution as a contrast agent, in order to obtain a better contrast effect in a tissue sample, thus facilitating the identificat ion of anatomical structures, the histomorphological evaluation and the potential use of µCT in the imaging diagnosis of lesions. Different parameters were evaluated for obtaining images in SkyScan 1172, in a biopsied piece, when impregnated in a 10 % formalin solution and in a 2 % elemental iodine solution, when impregnated for 24h and 48h. Contrast agent impregnation was evaluated using the Hounsfield unit. The use of µCT allowed the identification of sialoliths dispersed inside the biopsy specimen, while the impregnation with Elemental iodine 2 % for 24h resulted in a better contrast when compared to the other conditions. The use of the Hounsfield unit allowed an adequate evaluation of the contrast obtained when the different parameters of impregnation and image acquisition were applied. The comparison between the 3D images with and without a specific marker highlighted a better evidencing of the soft tissues, with an improvement in the contrast of the images, also allowing the ident ification of the glandular duct obstructed by the sialoliths, allowing a conclusive histopathological evaluation of the biopsied lesion.

RESUMEN: Este estudio tiene como objetivo demostrar, a través de un reporte de caso clínico, la aplicabilidad del uso de la microtomografía (µCT) en la evaluación histopatológica de una lesión de ránula en el piso de la cavidad oral y evaluar el uso de solución de yodo elemental al 2 % como agente de contraste, con el fin de obtener un mejor efecto de contraste en una muestra de tejido, facilitando así la identificación de estructuras anatómicas, la evaluación histomorfológica y el potencial uso de µCT en el diagnóstico por imágenes de lesiones. Se evaluaron diferentes parámetros para la obtención de imágenes en SkyScan 1172, en una pieza biopsiada, cuando se impregna en una solución de formalina al 10 % y en una solución de yodo elemental al 2 %, durante 24 h y 48 h. La impregnación del agente de contraste se evaluó utilizando la unidad Hounsfield. El uso de µCT permitió la identificación de sialolitos dispersos dentro de la muestra de la biopsia, mientras que la impregnación con Yodo Elemental al 2 % durante 24 h resultó en un mejor contraste en comparación con las otras condiciones. El uso de la unidad Hounsfield permitió una adecuada evaluación del contraste obtenido cuando se aplicaron los diferentes parámetros de impregnación y adquisición de imágenes. La comparación entre las imágenes 3D con y sin marcador específico destacó una mejor evidenciación de los tejidos blandos, con una mejora en el contraste de las imágenes, permitiendo además identificar el conducto glandular obstruido por los sialolitos, permitiendo una evaluación histopatológica concluyente de la lesión sometida a biopsia.

Removal of Toxic Metal Ions Using Poly(BuMA-co-EDMA) Modified with C-Tetra(nonyl)calix[4]resorcinarene.

A copolymer of poly(BuMA-co-EDMA) modified with C-tetra(nonyl)calix[4]resorcinarene was obtained via the impregnation method. The formation of the modified copolymer was confirmed and investigated using various techniques; in this way, the presence of calix[4]resorcinarene was confirmed by FT-IR spectroscopy and by high resolution transmission electron microscopy. The modified copolymer was used for the removal of highly toxic cations (Pb2+, Hg2+, and Cd2+) from aqueous solutions. To perform the removal, we used the batch sorption technique and the effects of time of contact, pH, and volume of sample on the effective sorption were determined. The best results were observed for Pb2+ extraction, which was comparatively more efficient. Adsorption-desorption experiments revealed that the modified copolymer could be used for several cycles without significant loss of adsorption capacity. Finally, the results showed that the modified copolymer application is highly efficient for the removal of lead ions from aqueous solutions.

LA DUREZA TOTAL DEL AGUA AFECTA LA MUDA, CALCIFICACIÓN, CRECIMIENTO Y SUPERVIVENCIA DE Cryphiops caementarius (PALAEMONIDAE) / The total water hardness affects molting, calcification, growth and survival of Cryphiops caementarius (Palaemonidae)

RESUMEN El objetivo de este estudio fue evaluar los efectos de diferentes niveles de dureza total del agua en la muda, calcificación del exoesqueleto, crecimiento y supervivencia de Cryphiops caementarius. Los camarones machos fueron colectados del río Pativilca (Lima, Perú) y cultivados en recipientes individuales dentro de acuarios (55 L). Se emplearon cuatro niveles de dureza total del agua (100, 200, 300 y 400 mg CaCO3 L-1), con tres repeticiones, respectivamente. Los camarones cultivados en agua con dureza de 300 mg L-1 tuvieron menor periodo de muda (26,7 días) y mayor frecuencia de mudas (tres mudas). El contenido de calcio del exoesqueleto del camarón incrementó (p < 0,05) de 25 a 31 % en agua con dureza de 100 y 400 mg L-1, respectivamente. El mayor grosor del exoesqueleto (144 -jm en cefalotórax y 131 μm en abdomen) fue obtenido en agua con dureza de 400 mg L-1 y el menor grosor (93 -jm en cefalotórax y abdomen) en 100 mg L-1. El crecimiento en longitud fue mayor (p < 0,05) en agua con durezas de 200 y 300 mg L-1. El crecimiento en peso fue similar (p > 0,05) entre tratamientos. La mayor supervivencia (> 94,4 %) se mantuvo en agua con durezas de hasta 300 mg L-1 y la menor supervivencia (77,8 %) fue con 400 mg L-1. La dureza total del agua de 200 y 300 mg L-1 es conveniente para el cultivo del camarón, pero dureza del agua mayor o menor a este rango afectan la muda, el crecimiento y la supervivencia por deficiencia o exceso de calcio acumulado, respectivamente en el exoesqueleto del camarón.

ABSTRACT The aim of this work was to evaluate the effects of different levels of total hardness on the molting, calcification of exoskeleton, growth and survival of Cryphiops caementarius prawn. Male prawns were collected from Pativilca river (Lima, Peru) and cultivated in individual containers inside aquariums (55 L). Four levels of the total hardness of water (100, 200, 300 and 400 mg CaCO3 L-1) were used, with three repetitions, respectively. Prawns cultured in water with hardness of 300 mg L-1 has a shorter molting period (26.7 days) and a higher frequency of molts (three molts). The calcium content of the prawn exoskeleton increased (p < 0.05) from 25 to 31 % in water with hardness of 100 and 400 mg L-1, respectively. The greatest thickness of the exoskeleton (144 -jm cephalothorax and 131 -jm abdomen) was obtained in water with a hardness of400 mg L-1 and the smallest thickness (93 -jm in the cephalothorax and abdomen) in 100 mg L-1. The growth in length was greater (p < 0.05) in water with hardness of 200 and 300 mg L-1. The weight growth was similar (p > 0.05) between treatments. The highest survival (> 94.4 %) was maintained in water with hardness up to 300 mg L-1 and the lowest survival (77.8 %) was at 400 mg L-1. The total hardness of 200 and 300 mg L-1 is suitable for prawn farming, but hardness high or lower than this range affects the molting, growth and survival due to deficiency or excess of accumulated calcium, respectively, in the prawn exoskeleton.

Evolutionary insights and brief review of Loxodes Ehrenberg, 1830 (Ciliophora, Karyorelictea, Loxodidae) with description of a new species from Mexico.

Karyorelictids are a group of ciliates inhabiting marine and freshwater biotopes and possessing a non-dividing macronucleus. We describe a new freshwater species based on morphology and the 18S rRNA gene sequence data. Loxodes tziscaensis n. sp. can be easily distinguished from other Loxodes species by the arrangement of the nuclear apparatus and features of the buccal and somatic ciliature. The current proposed 18S rRNA phylogeny of Loxodes, including seven Loxodes species, shows two morphologically well-supported groups. Group A (L. rostrum, type species; L. vorax and L. tziscaensis n. sp.) includes species with a single nuclear group (two macronuclei and one micronucleus), in contrast to species of group B, which possess more than one nuclear group (L. striatus, L. magnus, L. kahli, L. penardi, and L. rex). We propose that the last common ancestor of Loxodes was a marine Remanella-like species possessing a single nuclear group. The division and differentiation of the micronucleus into a new macronucleus and the retention of the old macronuclei, independently of cell division, may have been two crucial processes during the evolution and diversification of Loxodes species with one nuclear group into species with multiple nuclear groups.

Neural organization of the third optic neuropil, the lobula, in the highly visual semiterrestrial crab Neohelice granulata.

The visual neuropils (lamina, medulla, and lobula complex) of malacostracan crustaceans and hexapods have many organizational principles, cell types, and functional properties in common. Information about the cellular elements that compose the crustacean lobula is scarce especially when focusing on small columnar cells. Semiterrestrial crabs possess a highly developed visual system and display conspicuous visually guided behaviors. In particular, Neohelice granulata has been previously used to describe the cellular components of the first two optic neuropils using Golgi impregnation technique. Here, we present a comprehensive description of individual elements composing the third optic neuropil, the lobula, of that same species. We characterized a wide variety of elements (140 types) including input terminals and lobula columnar, centrifugal, and input columnar elements. Results reveal a very dense and complex neuropil. We found a frequently impregnated input element (suggesting a supernumerary cartridge representation) that arborizes in the third layer of the lobula and that presents four variants each with ramifications organized following one of the four cardinal axes suggesting a role in directional processing. We also describe input elements with two neurites branching in the third layer, probably connecting with the medulla and lobula plate. These facts suggest that this layer is involved in the directional motion detection pathway in crabs. We analyze and discuss our findings considering the similarities and differences found between the layered organization and components of this crustacean lobula and the lobula of insects.

Aspirin-Loaded Polymeric Films for Drug Delivery Systems: Comparison between Soaking and Supercritical CO2 Impregnation.

Polymeric implants loaded with drugs can overcome the disadvantages of oral or injection drug administration and deliver the drug locally. Several methods can load drugs into polymers. Herein, soaking and supercritical CO2 (scCO2) impregnation methods were employed to load aspirin into poly(l-lactic acid) (PLLA) and linear low-density polyethylene (LLDPE). Higher drug loadings (DL) were achieved with scCO2 impregnation compared to soaking and in a shorter time (3.4 ± 0.8 vs. 1.3 ± 0.4% for PLLA; and 0.4 ± 0.5 vs. 0.6 ± 0.5% for LLDPE), due to the higher swelling capacity of CO2. The higher affinity of aspirin explained the higher DL in PLLA than in LLDPE. Residual solvent was detected in LLDPE prepared by soaking, but within the FDA concentration limits. The solvents used in both methods acted as plasticizers and increased PLLA crystallinity. PLLA impregnated with aspirin exhibited faster hydrolysis in vitro due to the catalytic effect of aspirin. Finally, PLLA impregnated by soaking showed a burst release because of aspirin crystals on the PLLA surface, and released 100% of aspirin within 60 days, whereas the PLLA prepared with scCO2 released 60% after 74 days by diffusion and PLLA erosion. Hence, the scCO2 impregnation method is adequate for higher aspirin loadings and prolonged drug release.

Apoplasmic barrier in the extrafloral nectary of Citharexylum myrianthum (Verbenaceae).

MAIN CONCLUSION: The cytological changes underlying the formation of an apoplasmic barrier in the multi-layered extrafloral nectaries of Citharexylum myrianthum are compatible with the synthesis, transport and deposition of suberin. In terms of ontogenesis and function, the intermediate layers of these nectaries are homologous with the stalks of nectar-secreting trichomes. Anticlinal cell wall impregnations are common in trichomatic nectaries and their functions as endodermis-like barriers have been discussed because of possible direct effects on the nectary physiology, mainly in the nectar secretion and resorption. However, the cytological events linked to nectary wall impregnations remain little explored. This study documents the ontogenesis and the fine structure of the EFN cells, and cytological events linked to the wall impregnations of multi-layered extrafloral nectaries (EFNs) in Citharexylum myrianthum Cham. (Verbenaceae). EFNs are patelliform, and differentiated into (a) a multicellular foot, which is compound in structure and vascularised with phloem strands, (b) a bi-layered intermediate region with thickened cell walls and (c) a single-layered secretory region with palisade-like cells. EFNs are protodermal in origin, starting with a single protodermal cell and ending with the complex, multi-layered structure. The cell wall impregnations first appear in the very young EFN and increase towards maturity. Lipid patches (assumed to be suberin) are deposited on the inner faces of the primary walls, first along the anticlinal walls and then extend to the periclinal walls. On both walls, plasmodesmata remain apparently intact during the maturation of the EFNs. In the peripheral cytoplasm there are abundant polymorphic plastids, well-developed Golgi bodies often close to rough endoplasmic reticulum profiles, mitochondria and polyribosomes. Cytological events linked to the wall impregnations are consistent with suberin synthesis, transport and deposition. Our findings offer new insights into the structure-properties of specialised nectary cell walls and so should contribute to our knowledge of the physiological and protective roles of this structure in nectar glands.

Paraquat degradation by photocatalysis: experimental desing and optimization.

This study describes the experimental design and optimization of application TiO2 catalysts doped with 0.5, 1, 1.5, 2.0% of Fe. The catalysts were prepared using the impregnation method applied in Paraquat herbicide degradation. The catalysts were characterized by the following techniques: specific surface area and volume, mean pore diameter (BET method), scanning electron microscopy and photoacoustic spectroscopy. The characterization presented results indicating that both calcination temperature and the increase nominal metallic load affected by the structure of catalysts, changing the textural properties, as well as the band gap. The catalyst that presented the best herbicide removal percentage was TiO2 calcined at 773 K with removal of 90.2%. However, according to the experimental design and optimization, both variables (calcination temperature and Fe percentage) are significant in the process. In addition, a positive effect was found in the interaction between the two variables. The values show that a third order kinetic model better described the Paraquat photocatalytic degradation.