In the domain of production of flavor delivery systems based on carbohydrate matrices, Hot Melt Extrusion (HME) is one of the processes used which implies a relatively slow water evaporation step compared to Spray Drying or other common processes. The HME process of generating liquid syrup is stable only at industrial scales. The drying kinetic associated to the syrup formation is followed by collecting the vapored water. This experiment is exploited to estimate the diffusion coefficient of liquid water in a continuously concentrating carbohydrate melt ranging from 30.4 to 10.2%w/w water content and at temperatures ranging from 100 to 116 °C. A combination of Fick, Arnold and Vogel-Tammann-Fulcher models was used to derive the viscosity of the solution, the gradient thickness at the surface of the stirred solution and the diffusion coefficient of water in the liquid under boiling conditions. It is here demonstrated that under continuous boiling conditions, the water concentration gradient depth from the surface of the solution has a dimension that is comparable to the size of the hydrated carbohydrate molecules and the diffusion coefficient of water in boiling carbohydrate solutions ranges from 5.10−9 cm.s−2 for low temperature and high water content to 10−11 cm.s−2 for high temperature and low water content.
ᅟ
A series of heterocyclic and hydrocarbon [8]circulenes (also named completely annelated tetraphenylenes) were studied by the NICS and GIMIC methods in order to describe their aromatic properties from the magnetic criterion point of view. According to calculations all the hetero[8]circulene molecules demonstrate the bifacial aromatic/antiaromatic nature. The inner octatetraene core of the studied [8]circulenes is characterized by the presence of paratropic (“antiaromatic”) ring currents, whereas the outer macrocycle constructed from the five- and six-membered rings possesses the magnetically-induced diatropic (“aromatic”) ring current. The hydrocarbon [8]circulenes studied in this work consist of a similar planar cyclooctatetraene core but they exhibit a rather different balance of magnetically-induced ring currents.
Aromaticity of the completely annelated tetraphenylenes
A common goal of active packaging is to improve the shelf life, safety, or quality of packaged foods. The integrity of an active package must be remained in order to prevent the growth of microorganisms on the surface of food. Therefore, active polyvinyl alcohol-Alyssum homolocarpum seed gum (PVA-AHSG) composite films with different nisin concentrations (3000, 5000 and 10,000 IU) were prepared and their physico-chemical and antimicrobial properties were determined. Addition of nisin to the composite films increased their water vapor permeability (WVP), elongation at break (EB) and opacity, whereas their total color difference (ΔE), glass transition temperature (Tg), melting temperature (Tm), tensile strength (TS) and young modulus (YM) were decreased. Increasing the nisin concentration remarkably increased the chain mobility, interactions between polymers and water molecules and also the free volume of polymer matrix. The antimicrobial potential of film against L. monocytogene, S. aureus and E. coli as well as the release of nisin into phosphate buffer solution (pH 7.2) were investigated. Films containing nisin had inhibition effect against gram positive pathogens among which L. monocytogenes was the most sensitive bacterium. In liquid media, all films containing nisin prevented the growth of L. monocytogenes and S. aureus, but it was only the film with 10,000 IU nisin content which was able to control 100% of the microbial population during incubation time. Nisin release and diffusion coefficient (D) increased as its concentration increased in the film matrix due to the interaction of nisin with film polymer chains. Therefore, the resultant film had appropriate controlled release property and suitable microbial inhibitory against gram positive bacteria.
Composite bioactive films based on polyvinyl alcohol-Alyssum homolocarpum seed gum blend and Nisin: Physiochemical characterization and antimicrobial properties. Monjazeb et al. (2017).
The continuous availability of cells with defined cell characteristics represents a crucial issue in the biopharmaceutical and cell therapy industry. Here, development of cell banks with a long-term stability is essential and ensured by a cryopreservation strategy. The strategy needs to be optimized for each cell application individually and usually comprises controlled freezing, storage at ultra-low temperature, and fast thawing of cells. This approach is implemented by the development of master and working cell banks. Currently, empirical cryopreservation strategy development is standard, but a knowledge-based approach would be highly advantageous. In this article, we report the development of a video-based tool for the characterisation of freezing and thawing behaviour in cryopreservation process to enable a more knowledge-based cryopreservation process development. A successful tool validation was performed with a model cryopreservation process for the β-cell line INS-1E. Performance was evaluated for two working volumes (1.0 mL and 2.0 mL), based on freezing-thawing rates (20 °C to − 80 °C) and cell recovery and increase of biomass, to determine tool flexibility and practicality. Evaluation confirmed flexibility by correctly identifying a delay in freezing and thawing for the larger working volume. Further more, a decrease in cell recovery from 0.94 (± 0.14) % using 1.0 mL working volume to 0.61 (± 0.05) % using a 2.0 mL working volume displays tool practicality. The video-based tool proposed in this study presents a powerful tool for cell-specific optimisation of cryopreservation protocols. This can facilitate faster and more knowledge-based cryopreservation process development
Graphical abstractIn this study, a video-based analytical tool was developed for the characterisation of freezing and thawing behaviour in cryopreservation process development. Evaluation of the practicality and flexibility of the developed tool was done based on a scale-up case study with the cell line INS-1E. Here, the influence of sample working volume on process performance was investigated. Increasing the volume from 1to 2 mL led to a delay in freezing and thawing behaviour which caused cell recovery loss. We believe that the developed tool will facilitate more directed and systematic cryopreservation process development.
In the present work, a series of simulation tools were used to determine structure-activity relationships for the endomorphins (EMs) and derive μ-pharmacophore models for these peptides. Potential lowest energy conformations were determined in vacuo by systematically varying the torsional angles of the Tyr1-Pro2 (ω1) and Pro2-Trp3/Phe3 (ω2) as tuning parameters in AM1 calculations. These initial models were then exposed to aqueous conditions via molecular dynamics simulations. In aqueous solution, the simulations suggest that endomorphin conformers strongly favor the trans/trans pair of the ω1/ω2 amide bonds. From two-dimensional probability distributions of the ring-to-ring distances with respect to the pharmacophoric angles for EMs, a selectivity range of μ1 is ca. 8.3 ~ 10.5 Å for endomorphin-2 and selectivity range of μ2 is ca. 10.5 ~ 13.0 Å for endomorphin-1 were determined. Four-component μ-pharmacophore models are proposed for EMs and are compared to the previously published δ- and κ-pharmacophore models.
Angle NAB/C vs distance
Spodoptera frugiperda (J.E. Smith) is an invasive pest in agriculture. It can potentially damage yield resulting severe crop losses and subsequently significant economic damage each year. S. frugiperda is predominantly managed using traditional chemical pesticides. Accordingly, sustainable alternatives such as digestive enzymes inhibitors can be used as an efficient pest management that protects the environment. This contribution aims to examine the pro-region of S. frugiperda trypsin as specific inhibitor of the pest protease enzyme. Structural modeling in conjunction with molecular docking simulations were conducted to design a peptide sequence with the best docking scores and strong binding energy to the target enzyme. The structural models of six pro-peptides were produced based on modification of 7-amino acids of the pro-region of S. frugiperda trypsin. VERIFY_3D, ERRAT, PROCHECK, PROSA and WHAT-IF scores validated the reliability of the predicted model of S. frugiperda trypsin. Molecular docking studies between the six designed inhibitor peptides and the predicted model structure at three different pH conditions were carried out. Data revealed that VPSNPQR at pH 11.0 with the best docking score, the lowest binding energy (ΔG) and dissociation constant (Kd) indicated a potent binding affinity towards S. frugiperda trypsin’s active site. Moreover, the peptide showed a weak potential for interaction with the human trypsin. The results indicated the importance of computational studies in design and selection of inhibitor peptides against target enzymes. Such inhibitors can be used for S. frugiperda control, which can be further applied in other pest management programs.
Graphical AbstractDocking simulations between the pro-peptide inhibitor and Spodoptera frugiperda midgut trypsin confirmed the capacity of the designed pro-region in inhibiting the insect trypsin.
Dendrimeric copper nanoparticles (CuNPs) were prepared by the reduction of [Cu2(CH3CO2)4] with ascorbic acid at 75 °C in the presence of ranelate ions. The metallic nanoparticles exhibited a strong plasmonic band centered at 581 nm, and their average size distribution was typically in the range of 20–30 nm. By adding polyvinylpyrrolidone to the reaction mixture, the growth of the initial copper nanoparticles was hindered. Their sizes were stabilized around 1.8 nm, leading to spherical agglomerates of about 50 nm. Upon green light excitation, the agglomerates exhibited yellow-orange fluorescence emission, keeping the surface plasmon resonance band at 581 nm. This dual behavior suggested the occurrence of collective plasmonic resonance and efficient energy transfer within the agglomerated nanoparticles, in order to account for the observed fluorescence in the system.
Graphical Abstract
The present work aimed to investigate the antioxidant, anti-inflammatory and wound healing potential of ethyl acetate fraction from Bauhinia ungulata L. (FABU) on in vitro and in vivo models. Wound healing assay using human lung adenocarcinoma A549 cell line was employed to evaluate the ability of FABU in modulating cell migration. In addition, a surgical wound model in C57BL/6 mice was used to study the healing potential of FABU incorporated into gel carbomer 940 (Carbopol®). Evaluation of lipid peroxidation, inflammatory and anti-inflammatory mediator gene expression, rate of wound closure, and histological analysis were done. FABU significantly reduced the gap area in in vitro wound healing assay, 24 h after treatment. In the animal model, FABU at 0.5% topically applied once-daily for 5 days to the surgical wounds significantly reduced the lesion area. Moreover, it significantly decreased the levels of lipid peroxidation in the lesions and decreased the relative gene expression levels of IL-1β and TNF-α in the injured region. In conclusion, our study suggests that Bauhinia ungulata can effectively promote the wound healing, probably by regulating the inflammatory environment during the early stages of the process.
Graphic abstractWe report a simple and fast microwave-assisted method to grow silver nanoparticle films with tunable plasmon resonance band. Microwaving time controls nucleation and growth as well as particle agglomeration, cluster formation, particle morphology, and the plasmonic properties. Films produced with times shorter than 30 s presented a single well-defined plasmon resonance band (~ 400 nm), whereas films produced with times longer than 40 s presented higher wavelength resonances modes (> 500 nm). Plasmon band position and intensity can be easily tuned by controlling microwaving time and power. SEM and AFM images suggested the growth of asymmetrical silver nanoparticles. Simulated extinction spectra considering particles as spheres, hemispheres, and spherical caps were performed. The films were employed to enhance the sensitivity of ionizing radiation detectors assessed by optically stimulated luminescence (OSL) via plasmon-enhanced luminescence. By tuning the plasmon resonance band to overlap with the OSL stimulation (530 nm), luminescence enhancements of greater than 100-fold were obtained, demonstrating the importance of tuning the plasmon resonance band to maximize the OSL intensity and detector sensitivity. This versatile method to produce silver nanoparticle films with tunable plasmonic properties is a promising platform for developing small-sized radiation detectors and advanced sensing technologies.
Graphical Abstract
Resveratrol (RES) is a polyphenol with increasing interest for its inhibitory effects on a wide variety of viruses. Zika virus (ZIKV) is an arbovirus which causes a broad spectrum of ophthalmological manifestations in humans. Currently there is no certified therapy or vaccine to treat it, thus it has become a major global health threat. Retinal pigment epithelium (RPE) is highly permissive and susceptible to ZIKV. This work explored the protective effects of RES on ZIKV-infected human RPE cells. RES treatment resulted in a significant reduction of infectious viral particles in infected male ARPE-19 and female hTERT-RPE1 cells. This protection was positively influenced by the action of RES on mitochondrial dynamics. Also, docking studies predicted that RES has a high affinity for two enzymes of the rate-limiting steps of pyrimidine and purine biosynthesis and viral polymerase. This evidence suggests that RES might be a potential antiviral agent to treat ZIKV-induced ocular abnormalities.
Graphic abstract