Search

Miscible carbon dioxide (CO2) flooding is a well-established and promising enhanced oil recovery (EOR) technique whereby residual oil is recovered by mixing with injected CO2 gas. However, CO2, being very light and less viscous than reservoir crude oil, results in inefficient sweep efficiency. Extensive research is ongoing to improve CO2 mobility control such as the development and generation of CO2/water foams. The long-term stability of foam during the period of flooding is a known issue and must be considered during the design stage of any CO2 foam flooding project. The foam stability can be improved by adding surfactants as stabilizers, but surfactants generated foams have generally a shorter life because of an unstable interface. Furthermore, surfactants are prone to higher retention and chemical degradation in the porous media, particularly under harsh reservoir conditions. Research has shown that nanoparticles (NPs) can act as an excellent stabilizing agent for CO2/water foams owing to their surface chemistry and high adsorption energy. The foams generated using NPs are more stable and provide better mobility control compared to surfactant-stabilized foams. One limitation of using NPs as foam stabilizers is their colloidal stability which limits the use of low-cost NPs. Combining surfactants and NPs for CO2 foam stabilization is a novel approach and has gained interest among researchers in recent years. Surfactants improve the dispersion of NPs in the aqueous phase and minimize particle aggregation. NPs on the other hand create a stable barrier at the CO2/water interface with the help of surfactants, thus generating highly stable and viscous foams. This paper presents a comprehensive review of the basic principles and applications of stabilized CO2 foams. A brief overview of CO2 foam flooding is discussed first, followed by a review of standalone surfactant-stabilized and NPs-stabilized CO2/water foams. The application of hybrid surfactant-NPs stabilized CO2 foams is then presented and areas requiring further investigation are highlighted. This review provides an insight into a novel approach to stabilize CO2/water foams and the effectiveness of the method as proved by various studies.

BACKGROUND Peripheral, non-neuronal serotonin promotes the recruitment of neutrophils to sites of acute inflammation and tissue damage. Direct effects of serotonin on neutrophil function were shown to be involved. However, the influence of serotonin on the endothelial counterpart is unknown. OBJECTIVES To investigate whether serotonin alters the function of endothelial cells in leukocyte recruitment during acute inflammation. METHODS We used two murine models of acute inflammation: intraperitoneal lipopolysaccharide (LPS) injection and mesenteric ischemia/reperfusion injury (I/R). To study effects of peripheral serotonin, leukocyte recruitment and endothelial adhesion molecule expression were compared in wild type (WT) and tryptophan hydroxylase 1 deficient (Tph1-/- ) mice, which are unable to synthesize peripheral serotonin. RESULTS As expected, neutrophil transmigration into the peritoneal cavity following LPS injection was impaired in Tph1-/- mice. Abdominal blood vessels, however, showed no difference in adhesion molecule expression. In the early reperfusion phase after mesenteric I/R, the number of rolling leukocytes was significantly lower in Tph1-/- compared to WT. In line with the LPS model, endothelial adhesion molecule expression was independent of serotonin. In vitro experiments using human umbilical vein endothelial cells (HUVECs) confirmed that serotonin does not affect endothelial adhesion molecules. CONCLUSIONS The inflammatory release of peripheral serotonin is dispensable for the regulation of endothelial adhesion molecules.

Two novel chromophores with dibutylaniline donor moiety, 3,7-(di)vinylquinoxalinone π-electron bridge and tricyanofuranyl or dicyanovinyl acceptor moieties are synthesized and their properties were systematically investigated. Atomistic modeling of PMMA-based composites with the developed chromophores as guests is performed and nonlinear optical activity is studied for the first time. Atomistic modeling performed in the amorphous cell has shown that chromophore content 20 wt% may be considered most favorable for achievement of optimal d33 values for 7-DBA-VQonV-TCF/PMMA material. Various non-covalent interactions both between chromophores and polymer matrix and chromophores inter se were revealed in the course of modeling; these interactions could contribute to the relaxation stability of orientational order and thus quadratic NLO response. Composite material 7-DBA-VQonV-TCF/PMMA is characterized by nonlinear-optical coefficient, d33, values of 97, 111 and 47 pm/V at chromophore content of 10, 20 and 30 wt%, respectively. Thus chromophore content 20 wt% provides maximal value of NLO coefficient, what is in agreement with the obtained theoretical data. The d33 value for 7-DBA-VQonV-DCV/PMMA is 2.5 times smaller than that for 7-DBA-VQonV-TCF/PMMA at the same chromophore load (20 wt%).

Atomistic modeling of polymer materials based on linear methacrylic copolymers with nonlinear-optical (NLO) azochromophores in side chains, MMA-MAZ, is carried out. Polymer material is packed in a so-called amorphous cell with density close to that of the real polymer in the course of Simulated Annealing procedure or Multistage Simulation with compressive protocol. Glass transition temperature, Tg, of polymer material was estimated in the course of modeling for a number of systems differing by the length of copolymer chains; good agreement with the experimental data is obtained. Molecular dynamics (MD) at elevated temperatures allowed estimating the local mobility of chromophores and fragments of polymer chains. The chromophores are shown to reorient at temperature 30 K higher than the glass transition temperature of the MMA-MAZ material. MD revealed the presence of a variety of nonvalent interactions binding the chromophores and the fragments of the polymer chains, H-bonds and π-π-interactions are among them.

Zein, a corn protein, is often used for preparing edible films and coatings. Since zein is insoluble in water, zein films and coatings are usually prepared by spraying or casting its aqueous ethanol solutions to a contact surface (Zsol films). However, the use of organic solvents in many food applications is unwanted. In this work, aqueous dispersions of zein nanoparticles were prepared by antisolvent precipitation from 90% v/v aqueous ethanol zein solutions. Zein films were then prepared by casting the dispersions in silicone molds and air–drying at 50 °C (Zdis films). The obtained films were characterized for morphology, FTIR analysis, mechanical, water barrier and optical properties, and were benchmarked against Zsol films. It was found that continuous zein films can be prepared out of aqueous dispersions of zein nanoparticles. Zdis films proved to have grainy morphology and higher surface roughness when compared to Zsol. Surface roughness of Zdis films was decreased when plasticizer was added. Water barrier properties of Zdis films were found to be comparable to Zsol films. No differences in mechanical properties were found between Zsol and Zdis film. Size of zein particles influenced morphology and optical properties of zein dispersion films.

Two chromophores with π-deficient quinoxaline (Q) core in the π-electron bridge together with dibutylaniline (DBA) donor moiety and tricyanofuranyl (TCF) or dicyanovinyl (DCV) acceptor moieties have been synthesized to investigate their macroscopic nonlinear optical (NLO) activity in guest-host materials. A distinctive feature of the 7-DBA-VQPhV-TCF chromophore is predominance of negative solvatochromism over the positive one, which is quite rarely met for the chromophores manifesting inverse solvatochromic behavior as well as the blue shift of the absorption maximum compared to the chromophore FTC with divinylthiophene π-bridge. Introduction of quinoxaline moiety in the conjugated bridge promotes the increase of thermal stability: Td of both compounds is higher than 225 °C. Density functional theory was used to calculate the chromophores first hyperpolarizability (β). Quadratic NLO response characterized by d33 coefficient was measured by SHG technique for thin guest-host polymer films. The influence of chromophore content on the NLO coefficient of 7-DBA-VQPhV-TCF/PMMA film has been investigated and the d33 value of this film reaches 108 pm/V at 25 wt% load. The poled film 7-DBA-VQPh-DCV/PMMA shows twice smaller d33 values (30 pm/V) at the same chromophore load (20 wt%).

Objectives: To synthesise the existing reviews conducted on the labour market outcomes of cancer survivors by focusing on (i) the convergences and divergences on the overall work-related outcomes, (ii) the moderating factors studied to date, and (iii) an identification of areas where more research is needed in the future.Methods: A systematic review of the existing reviews on labour market outcomes for cancer survivors was performed. Bibliographic search for eligible studies published before January 2019 involved the following three core concepts: (i) cancer survivors, (ii) work, and (iii) review. The quality of the included reviews was assessed based on the Johns Hopkins Hospital Evidence Level and Quality Guide. Following this, a narrative synthesis of the findings was completed.Results: In total, 35 articles met the inclusion criteria. The average return to work (RTW) rate varied between 54% and 66%. The self-reported work ability was consistently lower following cancer. This review also found strong converging evidence of self-reported discrimination after cancer. The effects on work performance showed several inconsistencies, possibly due to the use of different definitions of work performance. Most moderating factors for successful work outcomes showed converging evidence, except for age, marital status, cancer type, and country. We provide several possible explanations and linkages for these divergencies.Conclusions: Further investigation of causal relationships by (i) using matched control groups and by (ii) gathering longitudinal data, and the use of more standardised definitions of the outcome variables are the two main future research recommendations. Furthermore, no studies have succeeded in measuring the work outcomes objectively. We provide specific recommendations from an interdisciplinary context to solve this. Protocol registration: CRD42019139386.

The methacrylate-based composite polymer materials with various weight content of azochromophores-guests – aminoazobenzenes with various acceptor moieties: AAB-NO2, AAB-DCV, AAB-TCV, and AAB-TCP, – are studied by atomistic modeling. Polymer matrices are PMMA, copolymer of methyl methacrylate and methacrylic acid, MMA-MAA, and copolymer MMA-MAZ, MAZ unit containing azochromophore, covalently attached to the side chain via spacer. The realization of various non-covalent interactions (hydrogen and π-π interactions) is considered, special emphasis is given to the role of chromophore structure and polymer matrix nature. It is shown that rather uniform distribution of chromophores in composite materials is retained even at 30 wt% content. In all composites with chromophore content growth both the number of non-covalently bound chromophores and the proportion of chromophores bound inter se increase, while the proportion of chromophores, bound with polymer matrix, decreases. The number of hydrogen bonds (HBs) between chromophores-guests is determined mostly by the nature of the acceptor group of the chromophore, maximum number of HBs being formed by AAB-TCP. The MMA-MAA matrix allows realization of greater number of inter-chain HBs compared to MMA-MAZ matrix, while such bonds are absent in PMMA. Azochromophores in MAZ units of MMA-MAZ matrix form π-π-stacking structures with mostly codirected chromophore dipole moments, besides AAB-TCV guests form such stacking structures with host matrix chromophores. Chromophores in MAZ units more easily interact with guests than with each other via π-π stacking. The studied matrices could be considered promising to be used as hosts at developing composite materials with quadratic nonlinear optical response.

Four chromophores belonging to a new class of push-pull chromophores with divinylphenylquinoxaline moieties have been designed and synthesized. The structure-property relationship was systematically investigated; the effect of the conformation on the value of chromophores first hyperpolarizability is found to be inessential. Quinoxaline-based chromophore with TCF acceptor and 7-dimethylanilinovinyl moiety displays the combination of favorable characteristics: the high value of the first hyperpolarizability, the small HOMO-LUMO energy gap, the blue shift of the absorption maximum relative to the chromophores with other divinylhetaryl or polyene π-bridges and ultrahigh thermal stability. This chromophore may be considered as a perfect candidate for the development of effective electro-optic materials.

For the first time bichromophore nonlinear optically active compounds, 3,5-bis [2- (N-ethyl-4- (4′-nitrophenylazo) anilino) ethoxy] benzyl alcohol, DF1, and 3,5-bis [6- (N-methyl-4- (4′-nitrophenylazo) anilino) hexaoxy] benzyl alcohol, DF2, have been synthesized. The synthesis of the epoxy-amine oligomers containing DF1 and DF2 dendritic fragments in the side chain was preceded by molecular design which demonstrated that the hexyl groups, binding the chromophores to the branching center in DF2, are able to provide greater mobility of the chromophores compared to the ethyl groups in DF1, thus determining the preference of the former from the viewpoint of NLO activity. Bi-chromophore compounds were introduced into the side chain of epoxy amine oligomers using the esterification reaction under mild conditions by the Steglich method. As a result, oligomers OAB-DF1 (Tg = 122 °C) and OAB-DF2 (Tg = 107 °C) were obtained with good yields, the degree of functionalization was 60 mol% and 45 mol%, respectively. The values of the NLO coefficients, d33, were measured by second harmonic generation technique; they are equal to 29 pm/V for OAB-DF1 and 40 pm/V for OAB-DF2.

In recent years, the incidence of Fusarium wilt in potato plants has steadily increased, in the Middle Volga Region of Russia. The current work aimed to investigate the structure of root mycobiota of the Zhukovskij rannij potato cultivar and assess the effect of growth stage on Fusarium populations in different compartments of the potato root. Using Amplicon-Based Next Generation Sequencing and relevant bioinformatic tools, we compared fungal communities and guilds of the bulk soil (alfisol) and root compartments (rhizosphere, rhizoplane) of potato plants at flowering vegetation and senescence. Root compartments were inhabited by 3 major phyla: Ascomycota (79.41–94.84%), Basidiomycota (2.27–7.68%), and Mucoromycota (1.32–9.81%) irrespective of the stage of development. Fusarium was among the dominant genera of the rhizosphere (11.07 ± 0.99) and rhizoplane (37.61 ± 0.77%) during flowering, while at senescence they were replaced by the closely related genus Monographella (42.38–43.80%), the abundance of which significantly superseded other taxa in the fungal community. Unlike the root, Fusarium populations in the bulk soil did not change, which confirms the role of the potato plant in assembling fungal taxa and guilds. FUNGuild analysis showed that the near root zone of the studied cultivar is highly populated with pathotrophs, irrespective of the growth stage. Thus, the alfisol of the studied region is densely populated with pathotrophs, and the concurrent assembly of phytopathogens and beneficial fungi by the root demonstrates that the recruitment process of alfisol-based symbionts may be insufficient in preventing the influx of pathotrophs during root mycobiome formation in the studied potato cultivar.

A comprehensive study was conducted on the fruits of 49 Ferula species, mostly from Central Asia, to describe the fruit surface microstructure and understand the systematic significance of this character for infrageneric delimitation. Ancestral states of the key morphometric characters were reconstructed via Mesquite, and distribution of informative characters at generic level was inferred using a Bayesian phylogenetic tree. In addition, chemical compound fingerprints for 21 Ferula species detected via HPLC-DAD were analysed with the COW algorithm in MATLAB 2019a, and optimised in a cladistic analysis, which showed incongruence with molecular data. This research aimed to define species groups within the economically important and taxonomically complex genus Ferula, and detected incongruence between the carpological, molecular and chemical data.