On the modeling of phase and chemical equilibria by equations of state for systems containing supercritical components and ionic species

A technique of modeling of phase and chemical equilibria by equations of state for systems containing supercritical components and ionic species is considered. Attention is focused on the structure of equation of states with inclusion of non-electrolyte and electrostatic contributions. A hole quasichemical model was applied to illustrate the technique and to show how an EOS can be modified for systems with chemical reactions and electrostatic interactions in the liquid phase. The concentration dependency of the density and dielectric permittivity was taken into account in describing the electrostatic contribution that is required for thermodynamic consistency of the results of modeling. A method of assessing the appropriate relationships for mixtures containing supercritical components is suggested, alongside with the way to estimate the “true” composition of mixtures where ionic species are formed due to chemical reactions. The raised questions are discussed with respect to the following systems: solutions of acid gases in water-alkanolamine mixtures and water-ammonia-carbon dioxide system in a broad interval of temperatures and pressures.     

Tunable Dielectric Function in Electric‐Responsive Glass with Tree‐Like Percolating Pathways of Chargeable Conductive Nanoparticles

The design of nanostructured materials with specific physical properties is generally pursued by tuning nanoparticle size, concentration, or surface passivation. An important step forward is to realize “active” systems where nanoparticles are vehicles for controlling, in situ, some specific, tuneable features of a responsive functional material. In this perspective, this work focuses on the rational design of a nanostructured glass with electrically tuneable dielectric function obtained by injection and accumulation of charge on embedded conductive nanocrystals. This enables electrically controlled switching of semiconducting nanophases to charged polarisable states to be achieved, which could lead to smart, field‐enhancement applications in nanophotonics and plasmonics. Here, it is shown that such response switching can be obtained if a percolating charge‐transport mechanism is activated through a disordered tree‐like network, as is demonstrated to be possible in SiO₂ films where suitable dispersions of SnO₂ nanocrystals, with conductive interfaces, are obtained as a result of a new synthesis strategy.     

A fully bio-based monomer derived from undecylenic acid,glycerol, and CO2 useful for the synthesis of polyhydroxyurethanes

Undecylenic acid, glycerol, and CO₂ were used as building blocks for obtaining a fully bio-based carbonated monomer, useful for polyurethanes. The functionality of the monomer was close to 3 cyclic carbonates/mol, located in terminal positions. In a first stage, a synthetic triglyceride was obtained with 99% selectivity by esterification of glycerol and undecylenic acid at 160°C. The triglyceride was then epoxidized using H₂O₂ and Amberlyst 15 or Amberlite IR-120 acidic exchange resins at 57°C. The selectivity to epoxide was kept constant at 98% using Amberlite IR-120. Terminal cyclic carbonates were then inserted through epoxide moieties under mild conditions by the chemical fixation of CO₂ at 80°C and 6 MPa in 6 h. A complete conversion was obtained in 6 h reaction while the selectivity to carbonate groups was near to 99% during all the reaction time. An elastomeric polyhydroxyurethane was obtained by aminolysis of the carbonated monomer with ethylenediamine at 70°C, affording a Young's modulus of 22.6 MPa and T_g of −15.2°C. The material showed a good thermal stability below 240°C.     

Characterization of Edible Active Coating Based on Alginate–Thyme Oil–Propionic Acid for the Preservation of Fresh Chicken Breast Fillets

Chicken meat presents serious problems of processing and storage. Edible coatings are used commercially to improve the shelf life of fresh foods. The aim of this study is to develop an effective antimicrobial edible coating to improve the shelf life and safety of fresh chicken meat. The effect of propionic acid and thyme essential oils as antimicrobial and antioxidant compounds incorporated into alginate‐based edible coating was evaluated. Physical, antimicrobial and sensorial analyses were performed in coated and uncoated samples. Sensorial analysis showed no significant differences between coated and uncoated samples, which do not influence the buying decisions of consumers. The pH of the meat surface, color and sensorial analysis changed during storage time, showing similar behavior between coatings, the principal parameters to determine the shelf life of this product were weight loss and microbiological deterioration, where coatings had different behaviors. The selected coating increased the shelf life by about 33% with the lowest dehydration.     

Formation Routes of Nanocomposite Coatings in Detonation Spraying of Ti3SiC2-Cu Powders

In thermally sprayed coatings, nano-sized features of the microstructure may be either inherited from the nanostructured agglomerates of the feedstock powder or form as a result of rapid cooling of molten particles upon deposition. Applying a process of the computer-controlled detonation spraying (CCDS) to Ti₃SiC₂-Cu composite powders produced by high-energy mechanical milling, we show that both routes are possible depending on the spraying conditions. When the nanostructure of the Ti₃SiC₂-Cu coating is inherited from the feedstock powder—under very mild conditions of detonation spraying, which exclude melting, so is the phase composition of the coating. In higher-temperature conditions of spraying, a significant fraction of the copper matrix melts and the interaction between Ti₃SiC₂ and Cu occurs. The TiC _x -Cu(Si) coatings that form show crystallites of both phases in the nano-range. In this case, rapid solidification of the molten fraction of the particles is responsible for the formation of the coatings with a nanostructured matrix. Due to the flexibility of the CCDS process, conditions of spraying were found such that a composite coating with very fine crystallites of the Cu(Si) matrix (30 nm) and a hardness of 273 HV could be obtained.     

Therapeutic Effects of hiPSC-Derived Glial and Neuronal Progenitor Cells-Conditioned Medium in Experimental Ischemic Stroke in Rats

Transplantation of various types of stem cells as a possible therapy for stroke has been tested for years, and the results are promising. Recent investigations have shown that the administration of the conditioned media obtained after stem cell cultivation can also be effective in the therapy of the central nervous system pathology (hypothesis of their paracrine action). The aim of this study was to evaluate the therapeutic effects of the conditioned medium of hiPSC-derived glial and neuronal progenitor cells in the rat middle cerebral artery occlusion model of the ischemic stroke. Secretory activity of the cultured neuronal and glial progenitor cells was evaluated by proteomic and immunosorbent-based approaches. Therapeutic effects were assessed by overall survival, neurologic deficit and infarct volume dynamics, as well as by the end-point values of the apoptosis- and inflammation-related gene expression levels, the extent of microglia/macrophage infiltration and the numbers of formed blood vessels in the affected area of the brain. As a result, 31% of the protein species discovered in glial progenitor cells-conditioned medium and 45% in neuronal progenitor cells-conditioned medium were cell type specific. The glial progenitor cell-conditioned media showed a higher content of neurotrophins (BDNF, GDNF, CNTF and NGF). We showed that intra-arterial administration of glial progenitor cells-conditioned medium promoted a faster decrease in neurological deficit compared to the control group, reduced microglia/macrophage infiltration, reduced expression of pro-apoptotic gene Bax and pro-inflammatory cytokine gene Tnf, increased expression of anti-inflammatory cytokine genes (Il4, Il10, Il13) and promoted the formation of blood vessels within the damaged area. None of these effects were exerted by the neuronal progenitor cell-conditioned media. The results indicate pronounced cytoprotective, anti-inflammatory and angiogenic properties of soluble factors secreted by glial progenitor cells.     

Identification,Synthesis, and Behavioral Activity of 5,11-Dimethylpentacosane,A Novel Sex Pheromone Component of the Greater Wax Moth,Galleria Mellonella (L.)

The greater wax moth, Galleria mellonella (L.), is a serious and widespread pest of the honeybee, Apis mellifera L. In contrast to most moths, for which long-range mate finding is mediated by female-produced sex pheromones, G. mellonella males attract conspecific females over long distances by emitting large amounts of a characteristic scent in combination with bursts of ultrasonic calls. The male scent for this species was previously identified as a blend of nonanal and undecanal. When these compounds were bioassayed, characteristic short-range sexual behavior, including wing fanning, was triggered in conspecific females, but the aldehyde blend failed to elicit attraction over longer distances. We identified, via analysis and synthesis, a third male-specific compound, 5,11-dimethylpentacosane. We show that it acts as a behavioral synergist to the aldehydes. In wind tunnel experiments, very few female moths responded to the aldehyde blend or to 5,11-dimethylpentacosane tested separately, but consistently showed orientation and source contact when a combination of all three compounds was applied. The level of attraction to the three-component mixture was still lower than that to male extract, indicating that the composition of compounds in the synthetic blend is suboptimal, or that additional pheromone components of G. mellonella are yet to be identified. The identification of 5,11-dimethylpentacosane is an important step for the development of an efficient long-range attractant that will be integrated with other environmentally safe strategies to reduce damage to beehives caused by wax moths.     

Detection of multiple disease indicators by an autonomous biomolecular computer

The promise of biomolecular computers is their ability to interact with naturally occurring biomolecules, enabling in the future the development of context-dependent programmable drugs. Here we show a context-sensing mechanism of a biomolecular automaton that can simultaneously sense different types of molecules, allowing future integration of biomedical knowledge on a broad range of molecular disease symptoms in the decision of a biomolecular computer to release a drug molecule.     

Response time variability

Response time variability is a new optimization problem with a broad range of applications and a distinctive number of theoretic flavour. The problem occurs whenever events, jobs, clients or products need to be sequenced so as to minimize the variability of time for which they wait for the next turn in obtaining the resources necessary for their advance. The problem has numerous real-life applications. We study its computational complexity, present efficiency, polynomial time algorithms for some cases, and the NP-hardness proof for a general problem. We propose a position exchange heuristic and apply it to improve the total response time variability of an initial sequence. The latter is the optimum bottleneck sequence, Webster or Jefferson sequence of the apportionment, or a random sequence. We report on computational experiments with the heuristic.