Determination of Psoralens in Child Food (Soups and Baby Food) from Brazil by High-performance Liquid Chromatography (HPLC)

Psoralens are considered natural toxins, present in edible plants, which act as protectors against fungi, insects, and herbivores. In this study, an analytical procedure suitable for sample preparation and an HPLC-UV method were developed for the quantification of psoralens in child food (soups and baby food). The samples were lyophilized and 5.00 g of solid was extracted with 25 mL of MeOH:HCl (1000:1), under magnetic stirring at 40 °C for 30 min. Separation was carried out on a C18 column with a mobile phase consisting of acetonitrile (20 to 100%) and water. Spectrophotometric detection with a wavelength of 246 nm was used. The method to determine psoralens in child food showed adequate linearity, repeatability, and accuracy. The limits of detection (LOD) and quantification (LOQ) obtained for psoralens were 0.02 and 0.08 μg g^?1, respectively. The concentrations (minimum–maximum in μg/100 g) of psoralens in the samples ranged from 71.9 to 877.4. The intake of approximately 45-mg psoralen and UVA exposure can result in various skin lesions. Therefore, the results showed that the developed method is simple, fast, and reliable for the determination of psoralens in child food (soups and baby food).     

Comparative evaluation of vegetable matter involved lesions with oral parasitic infections in the oral cavity

The current research aims to perform a comparative evaluation of vegetable matter involved lesions with oral parasitic infections found in oral mucosa, presenting histochemical methods to differentiate their microscopic similarities. Eight cases were selected out of a sample of 1.975 reports from a single Oral and Maxillofacial Pathology Service of the author's institution from 2012 to 2019. Specimens were examined by hematoxylin and eosin staining (HE), periodic acid-Schiff (PAS) staining, Gomori–Grocott staining, Ziehl–Neelsen staining, Giemsa, and mucicarmine staining. Microscopic analysis included fluorescence, polarized light, and confocal microscopy. Microscopically, in HE coloration, hookworm eggs showed as eosinophilic. Inflammatory multinucleated giant cells and lymphocytes, were usually related to the nematode eggs, forming an intense inflammatory infiltrate. Biofluorescent properties of eggs and larvae revealed to be sensitive in the detection of parasitic structures contrasting with the inflamed connective tissue. Vegetable presence was confirmed by polarized light microscopy and it was found to be associated with microbial biofilms. Confocal microscopy has showed to be an excellent method for morphotype differentiation of parasitic eggs. Parasitic infection and vegetable matter displayed similarities in the inflammatory response, but the latter can rot and agglomerate biofilms. The microscopic diagnosis of such infections requires the interpretation of challenging morphological features since the parasites are usually sectioned and mixed with an inflammatory reaction. These histochemical approaches proved to be excellent to distinguish both lesions.     

Interpreting the dioxin and furan profiles in the lichen Ramalina canariensis Steiner for monitoring air pollution

The purpose of this study was to compare the dioxin and furan (PCDD/F) profiles in lichens with those of air and soil. Lichen samples of the species Ramalina canariensis Steiner were collected from 44 different sites and analysed. The results were compared to PCDD/F air and soil profiles from bibliographic data concerning several countries and locations. When compared to other biomonitors (pine needles, vegetation, fruits), lichens were observed to accumulate greater concentrations of PCDD/Fs. The results showed that, although the concentrations of PCDD/Fs in lichens were at the same level of magnitude as those found for soils from the same country (197.5-1218.7 ng kg(-1) and 2.3-15.2 ng I-TEQ kg(-1)), the PCDD/Fs profiles do not reflect soil particle contamination. On the contrary, the PCDD/Fs lichen profiles seemed to be very similar to the ones in the air, at least for the diversity of the ones used for comparison in this study. These results indicated that lichens of the species R. canariensis are potential biomonitors of PCDD/F air pollution.     

Interaction between bradykinin potentiating nonapeptide (BPP9a) and β-cyclodextrin: A structural and thermodynamic study

Herein, we demonstrate the physical and chemical characterizations of the supramolecular complex formed between β-cyclodextrin (βCD) and bradykinin potentiating nonapeptide (BPP9a), an endogenous toxin found in Bothrops jararaca. Circular dichroism results indicate a conformational change in the BPP9a secondary structure upon its complexation with βCD. Nuclear magnetic resonance results, mainly from NOESY experiments, and theoretical calculations showed a favorable interaction between the tryptophan residue of BPP9a and the βCD cavity. Thermodynamic inclusion parameters were investigated by isothermal titration calorimetry, demonstrating that βCD/BPP9a complex formation is an exothermic process that results in a reduction in entropy. Additionally, in vitro degradation study of BPP9a against trypsin (37 °C, pH 7.2) showed higher stability of peptide in presence of βCD. This βCD/BPP9a complex, which presents new chemical properties arising from the peptide inclusion process, may be useful as an antihypertensive drug in oral pharmaceutical formulations.     

Intensification of photocatalytic pollutant abatement in microchannel reactor using TiO2 and TiO2‐graphene

A microfluidic device was applied to the photocatalytic degradation of methylene blue as a model pollutant. Titanium dioxide nanoparticles (TiO₂–P25) and a synthesized composite TiO₂‐graphene catalyst were immobilized on the inner walls of a borosilicate glass microfluidic chip. The deposition evolution of the nanoparticles was evaluated by monitoring the optical profile of the system. It was found that a higher initial reaction rate was obtained in the microreactor containing composite catalyst (TiO₂‐GR) on the inner walls, but both systems (TiO₂ and TiO₂‐GR) achieved similar reaction rates when the steady‐state was reached. Decolorization rate of methylene blue in our microfluidic chips was found to be approximately one order of magnitude higher than equivalent macroscopic systems reported in the literature at similar experimental conditions. Additionally, computational simulations were performed to investigate the physics involved in these processes. The model was experimentally validated for further scale‐out studies. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2794–2802, 2016     

High fidelity prototyping of PDMS electrophoresis microchips using laser-printed masters

Microsystem Technologies - Toner-based fabrication technology has appeared as one of the simplest and fastest techniques to produce low-cost microfluidic devices. The instrumental simplicity and...     

Gamma Irradiation Processing on 3D PCL Devices—A Preliminary Biocompatibility Assessment

Additive manufacturing or 3D printing applying polycaprolactone (PCL)-based medical devices represents an important branch of tissue engineering, where the sterilization method is a key process for further safe application in vitro and in vivo. In this study, the authors intend to access the most suitable gamma radiation conditions to sterilize PCL-based scaffolds in a preliminary biocompatibility assessment, envisioning future studies for airway obstruction conditions. Three radiation levels were considered, 25 kGy, 35 kGy and 45 kGy, and evaluated as regards their cyto- and biocompatibility. All three groups presented biocompatible properties, indicating an adequate sterility condition. As for the cytocompatibility analysis, devices sterilized with 35 kGy and 45 kGy showed better results, with the 45 kGy showing overall improved outcomes. This study allowed the selection of the most suitable sterilization condition for PCL-based scaffolds, aiming at immediate future assays, by applying 3D-customized printing techniques to specific airway obstruction lesions of the trachea.