Effect of cloisite 30B on the thermal and tensile behavior of poly(butylene adipate-co-terephthalate)/poly(vinyl chloride) nanoblends

Ternary PBAT/PVC/C30B nanoblends were successfully prepared via melt blending process at 130 °C and characterized by different techniques. The properties of the elaborated PBAT/PVC/C30B nanoblends were compared with those of the nonfilled PBAT/PVC blends to examine the C30B effects on the structure and properties of PBAT/PVC/C30B nanoblends. FTIR spectra revealed the presence of specific interactions between C=O of PBAT and acidic hydrogen of PVC, supporting the formation of miscible nanoblends. The PBAT/PVC/C30B morphology was investigated by both X-ray diffraction and transmission electron microscopy analyses. It was suggested the formation of mixed intercalated/partially exfoliated structures. Differential scanning calorimetry thermograms of PBAT/PVC/C30B nanoblends exhibited a single T _g and a full disappearance of the PBAT melting endotherm, confirming the complete compatibilization between PVC and PBAT. It was found that the T _g of the nanoblends were higher than those of the pristine blends due to their mixed intercalated/partially exfoliated structures. PBAT and PVC chains would be confined in a same C30B gallery causing a reduction of the chain mobility. Nanoblends showed a reduction of their thermal stability compared to their pristine blends, as a result of the catalytic effect of the C30B in the thermal degradation process. Tensile measurements displayed an improvement of mechanical properties for the ternary PBAT/PVC/C30B nanoblends relative to their virgin blends due to the insertion of clay particles into composite matrix.     

Upregulation of Cathepsin X in Glioblastoma: Interplay with γ-Enolase and the Effects of Selective Cathepsin X Inhibitors

Glioblastoma (GBM) is the most common and deadly primary brain tumor in adults. Understanding GBM pathobiology and discovering novel therapeutic targets are critical to finding efficient treatments. Upregulation of the lysosomal cysteine carboxypeptidase cathepsin X has been linked to immune dysfunction and neurodegenerative diseases, but its role in cancer and particularly in GBM progression in patients is unknown. In this study, cathepsin X expression and activity were found to be upregulated in human GBM tissues compared to low-grade gliomas and nontumor brain tissues. Cathepsin X was localized in GBM cells as well as in tumor-associated macrophages and microglia. Subsequently, potent irreversible (AMS36) and reversible (Z7) selective cathepsin X inhibitors were tested in vitro. Selective cathepsin X inhibitors decreased the viability of patient-derived GBM cells as well as macrophages and microglia that were cultured in conditioned media of GBM cells. We next examined the expression pattern of neuron-specific enzyme γ-enolase, which is the target of cathepsin X. We found that there was a correlation between high proteolytic activity of cathepsin X and C-terminal cleavage of γ-enolase and that cathepsin X and γ-enolase were colocalized in GBM tissues, preferentially in GBM-associated macrophages and microglia. Taken together, our results on patient-derived material suggest that cathepsin X is involved in GBM progression and is a potential target for therapeutic approaches against GBM.     

Lipid oxidative changes in chitosan-oregano coated traditional dry fermented sausage Petrovská klobása

The effect of a chitosan coating with added essential oil of oregano (Origanum vulgare) on lipid oxidation of dry fermented sausage (Petrovská klobása) was investigated. Fatty acid profile, aldehyde contents and sensory analysis of odor and flavor were determined after drying and during seven months of storage.     

Implementation of Artificial Neural Networks in Modeling the Water-Air Temperature Relationship of the River Drava

Water temperature directly affects the physical, biological and chemical characteristics of the river and determines the fitness and life of all aquatic organisms. It has direct and indirect effects on nearly all aspects of stream ecology. Accurately estimating water temperature is a complex problem. The purpose of this article is to analyze the relationship between the air and water temperature of the River Drava by constructing an artificial neural network (ANN) model and choosing appropriate network architectures for the River Drava’s daily river water temperature as well as demonstrating its application in improving the interpretation of the results. A linear regression model, as well as a stochastic model are also constructed and compared to ANN models consisting of a multilayer perceptron neural network and a radial basis function network. The results indicate that the ANN models are much better models and that ANNs are powerful tools that can be used for the estimation of daily mean river temperature.     

Synthesis and evaluation of some new oxazolones and imidazolones as antioxidant additives for Egyptian lubricating oils

Oxazolone derivative 2 was utilized as a key intermediate for synthesis of some new oxazolone and imidazolone derivatives. Reaction of oxazolone derivative 2 with diamines under different conditions afforded the corresponding imidazolone derivatives 3-8, respectively. Moreover, oxazolone 2 reacted with some heterocyclic amines in glacial acetic acid giving the corresponding imidazolone derivatives 9-14, respectively. Cyclocondensation of thiosemicarbazide with compound 2 in dry pyridine afforded compound 15. Addition of secondary amines to olefin double bond of compound 2 gave the corresponding addition products 16-19, respectively. Michael addition of compound 2 with some active methylene compounds afforded oxazolone derivatives 20-23, respectively. These prepared products were evaluated as antioxidant and corrosion inhibitors for gasoline lubricating oil and compounds 6a-c, 10 and 15 exhibited the highest antioxidant and anticorrosive activities. The effect of concentration of additives was studied to recommend the optimum concentration to be used. The results showed, for additive 15, 0.1 g for 1 L oil was the more effective concentration. Measurements for thermal analysis and of surface tension of oil after oxidation were also carried out.     

Dual Escherichia coli DNA Gyrase A and B Inhibitors with Antibacterial Activity

The emergence of multidrug-resistant bacteria is a global health threat necessitating the discovery of new antibacterials and novel strategies for fighting bacterial infections. We report first-in-class DNA gyrase B (GyrB) inhibitor/ciprofloxacin hybrids that display antibacterial activity against Escherichia coli. Whereas DNA gyrase ATPase inhibition experiments, DNA gyrase supercoiling assays, and in vitro antibacterial assays suggest binding of the hybrids to the E. coli GyrA and GyrB subunits, an interaction with the GyrA fluoroquinolone-binding site seems to be solely responsible for their antibacterial activity. Our results provide a foundation for a new concept of facilitating entry of nonpermeating GyrB inhibitors into bacteria by conjugation with ciprofloxacin, a highly permeable GyrA inhibitor. A hybrid molecule containing GyrA and GyrB inhibitor parts entering the bacterial cell would then elicit a strong antibacterial effect by inhibition of both the GyrA and GyrB subunits of DNA gyrase and potentially slow bacterial resistance development.     

Intensification of Mass Transfer in the Extraction Process with a Nanofluid Prepared in a Natural Deep Eutectic Solvent

The phytotoxic residues after olive oil production and residue leaves after pruning contain valuable bioactive compounds. A natural deep eutectic solvent (NADES) and an ethanol-water mixture were used for polyphenol extraction from olive pomace and leaves. Type of solvent, extraction temperature, and particle size of the leaves were optimized. NADES demonstrated better efficiency in the extraction process than conventional solvents; with higher temperature and smaller fraction of olive leaves, a higher yield of polyphenols was obtained from leaves. Extraction with a nanofluid as solvent was carried out. A stable nanofluid was prepared from NADES by adding Al₂O₃ nanoparticles. A higher yield was obtained with nanofluid from leaves, while an improvement of polyphenol extraction was achieved after the removal of oil from olive pomace.     

Synergetic association of grafted PLA and functionalized graphene on the properties of the designed nanocomposites

The synergetic association of poly(lactic acid) grafted with maleic anhydride (MA-g-PLA) containing 0.44 wt% of maleic anhydride and epoxy-functionalized graphene (GFe) on the properties of the designed nanocomposites was studied. Rheological, mechanical and barrier properties of PLA nanocomposites were studied using different content of epoxy-functionalized graphene and MA-g-PLA compatibilizer. The PLA/MA-g-PLA/GFe nanocomposites prepared by melt blending, containing 5 wt% of MA-g-PLA, yield a maximum in storage modulus G′ and a rheological plateau at low frequencies, with a content of epoxy-functionalized graphene comprised between 4 and 7 wt%. This phenomenon was ascribed to a pseudo-solid behavior resulting from the high degree of epoxy-functionalized graphene exfoliation due to strong interfacial interactions with PLA and epoxy-functionalized graphene. The better mechanical and barrier performances were obtained with PLA/GFe containing 10 wt% of epoxy-functionalized graphene and 5 wt% of MA-g-PLA compatibilizer. The variation of the percentage of compatibilizer showed that 5 wt% of maleated PLA was sufficient to improve the thermal, rheological, mechanical and barrier properties of the PLA nanocomposite containing 7 wt% of epoxy-functionalized graphene.     

Characteristics of Microencapsulated Palm-Based Oil as Affected by Type of Wall Material

Microcapsules containing a blend of red palm olein (red POo) and refined, bleached and deodorised palm stearin (RBD POs) in the ratio of 60:40 were prepared with various wall materials using a spray-drying technique. The total oil content of the microcapsules ranged from 398 to 683·2gkg⁻¹. Surface oil and moisture content varied from 38·8 to 158·9gkg⁻¹ and 25 to 30gkg⁻¹, respectively. Carotene retention after spray-drying and after storage depended on the oil content and types of wall materials, and ranged from 194·65 to 215·28 and 158·8 to 203·1mgkg⁻¹, respectively. Microcapsules with the best characteristics were made from wall material containing proteinaceous material.