Predicting the Stability of Emulsions in the Presence of Surfactants and Nanoparticles Using Coarse-Grained Simulations

Understanding the molecular mechanisms and processes that control the stability of emulsions is of great interest for many practical applications. Both surfactants and particles have been developed and optimised to control the emulsions stability. Due to the complexity of the emulsion system, it is challenging to understand the effect of these emulsifiers on the various demulsification processes, which can occur simultaneously or consecutively during phase separation. Molecular dynamics simulations are useful to identify some of the molecular mechanisms responsible for emulsions stability by providing algorithms designed to study the phenomena of interest. This work presents advances obtained via the implementation of the coarse-grained Dissipative Particle Dynamic simulation framework, DPD. First, a systematic approach was conducted to estimate the parameters to describe immiscible liquids containing surfactants. Starting from the Hansen theory of solutions, the model proved its ability to reproduce experimental water/oil interfacial tension as well as the micellar properties of aqueous non-ionic surfactants representative of the octyl polyethylene oxide family. Using this model, an algorithm was designed to study the Ostwald ripening phenomenon in an oil-in-water emulsion. The DPD simulation results are consistent with theoretical expectations, as well as with experimental observations. When surfactants were introduced to the system, the results show an enhancement in the emulsion stability due to the reduction in the interfacial tension, with a possible effect of the surfactant film properties on the Ostwald ripening rate. Finally, the effect of particle size on the arrangement of nanoparticles (NPs) on a curved oil/water interface was investigated. The arrangement of NPs showed a dependency on the particle size when the emulsion was subjected to a change in the NP-NP interaction, with a prompt self-organization of the smaller NPs. When a mixture of NPs of different sizes were introduced to the system, the NPs self-assembly on the droplet surface showed a dependency on the initial configuration. These findings could prove useful to understand the morphological changes occurring in Pickering emulsions affecting their stability, when subjected to a change in the interaction between its constituents

Diagnostic value of apparent diffusion coefficient (ADC) in assessment of pituitary macroadenoma consistency

AbstractBackgroundPre-operative assessment of macroadenoma consistency is helpful for proper surgical planning. DWI correlated with ADC value adding information about the tumor consistency that cannot be obtained with cMRI.Patients and methodsThirty patients with pituitary adenomas were examined by MRI including cMRI (conventional magnetic resonance) and DWI (diffusion weighted imaging) with ADC value measurement. Diagnosis was correlated with intra-operative finding and histopathology.ResultsAccording to ADC values, we classified our cases into three groups of macroadenoma consistency; Group A (Soft tumors=22/30) had mean ADC value of 0.482×10−3mm2/s, Group B (intermediate consistency=5/30) had mean ADC value of 0.730×10−3mm2/s and Group C (Firm adenomas=3/30) with mean ADC value of 0.992×10−3mm2/s. Diagnostic overlap was detected in one case of group A and 2 cases of group B. The sensitivity, specificity, PPV, NPD and accuracy of ADC values were 80%, 88%, 57.1% and 95.7% at ADC 0.7×10−3mm2/s and 100%, 88%, 62.5% and 100% at ADC 0.6×10−3mm2/s respectively.ConclusionDWI that correlated with ADC value should be included in routine pre-operative assessment of macroadenoma consistency. We recommend a cut off value of 0.6×10−3mm2/s, for accurate discrimination of the intermediate/soft macroadenomas from firm adenomas

Exceptive constructions: A Dependency-based Analysis

International audienceThe goal of this paper is to provide a description of the syntax of exceptive constructions within a dependency framework. These constructions are introduced in English by the markers except, but, except for, apart from, other than, etc. Examining their syntactic properties across a variety of languages shows that they imply two main types of constructions: The paradigmatic-EC and the hypotactic-EC. The first type shares many properties with coordination, and it can be integrated into the paradigmatic lists/piles phenomena in which two segments of the utterance pile up on the same syntactic position and whose most famous case is coordination

Molecular modelling and synthesis of novel ligands related to cellular differentiation

Cancer is a leading cause of death all over the world. Retinoic acid and vitamin D3 play an important role in cellular proliferation and differentiation and as such have potential therapeutic value as differentiating agents in the treatment of cancer and hyperkeratinising diseases. The use of differentiating agents to suppress prostate and breast cancer proliferation is now one of the new therapeutic strategies. However, the use of all trans retinoic acid (ATRA) and vitamin D3 as differentiating agents is limited by their rapid metabolism through the self induction of the cytochrome P450 enzymes that are involved in their catabolism. The P450 enzymes responsible for the metabolism of ATRA and la,25-(OH)2-D3 (calcitriol) are cytochrome P450 26 (CYP26A1) and cytochrome P450 24 (CYP24A1) respectively. Therefore the use of potent and selective inhibitors of CYP26A1 and CYP24A1 with ATRA and la,25-(OH)2-D3 respectively may represent a new strategy for the treatment of cancer. The pharmacophore model of CYP26A1 inhibitors was constructed using MOE software. A database of 71 inhibitors with different conformations have been built and arranged according to activity. The resulting pharmacophore model has 8 features of which 5 features are essential to get the CYP26A1 inhibitory activity. The designed model was used to build new inhibitors, which have reasonable activity. Two series were synthesised for CYP26A1 inhibition. The first series was designed to investigate the effect of changing the structure of the lead compound on the inhibitory activity against CYP26A1 and was depending mainly on presence of imidazole moiety, and the second series was a result of the pharmacophore search and was mainly oxadiazole derivatives. These two series were biologically evaluated using a MCF-7 breast cancer cell assay previously described by our group and also some of the compounds were tested in the biochemical assay. Changing of the structure could be tolerated to a certain limit as long as the imidazole ring is included which is the main part responsible for the binding with the haem in CYP26A1 enzyme. Some of the resulting compounds has good activity, specially methyl w-3-(1-1-imidazolyl)-3-4-(phenylamino)phenyl-2-methylpropanoate which should IC50 of 26 nM in the biochemical CYP26A1 assay. The oxadiazole derivatives did not show very good activity against CYP26A1 cell based assay, may be owing to the decrease in the.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Modeling the Performance in a Just in Time Context Using Goal Programming Approach

Sustaining philosophical and technological transformations (Just in time production, Total Quality Management, Robotic, New information technologies etc.), requires the evaluation systems of performance that are supposed to play a role of assistance and managerial decision aid, to regularly accompany these transformations. This paper proposes a multi-criteria methodology for global performance evaluation of each enterprise, which operates within Just In Time philosophy that is based on Goal programming from a non-exhaustive set of performance indicators, which reflect the degree of achievement of preliminary fixed objectives (zero stock, zero delay, zero breakdown, zero paper and zero defect),within this proposition a multi-criteria procedure, which takes into account the enterprise specificities, was developed

New insights into smudge cell percentage in chronic lymphocytic Leukemia: A novel prognostic indicator of disease burden

Background: Percentage of smudge cells in CLL patients has recently been reported as a novel prognostic factor.Objectives: To investigate the impact of smudge cells percentage on the clinicolaboratory data of CLL patients and to evaluate the relationship between it and other prognostic factors in CLL.Methods: Ninety adults with CLL were enrolled. Smudge cells percentage was calculated by microscopic evaluation of blood smears. Testing of CD38 expression was done by immunophenotyping and detection of ATM, P53 deletions and trisomy 12 were performed using fluorescent in situ hybridization (FISH)Results: Lower smear cells percentage (<30%) was significantly correlated with age, lymphadenopathy, organomegaly and advanced staging. It was also associated with high TLC, low hemoglobin and platelets count and high absolute and atypical lymphocytic count. Correlation studies with other prognostic factors revealed an association between low smear cells percentage and CD38 expression, short LDT, P53 and ATM deletions. Logistic regression analysis was also done to provide complementary prognostic information identifying the significant independent factors that predict low smear cell percentage.Conclusion: low percentage of smudge cells (<30%) could be considered as an adverse prognostic predictor being associated with high risk markers in CLL.Keywords: Smudge cells, CL

Molecular modelling and synthesis of novel ligands related to cellular differentiation.

Cancer is a leading cause of death all over the world. Retinoic acid and vitamin D3 play an important role in cellular proliferation and differentiation and as such have potential therapeutic value as differentiating agents in the treatment of cancer and hyperkeratinising diseases. The use of differentiating agents to suppress prostate and breast cancer proliferation is now one of the new therapeutic strategies. However, the use of all trans retinoic acid (ATRA) and vitamin D3 as differentiating agents is limited by their rapid metabolism through the self induction of the cytochrome P450 enzymes that are involved in their catabolism. The P450 enzymes responsible for the metabolism of ATRA and la,25-(OH)2-D3 (calcitriol) are cytochrome P450 26 (CYP26A1) and cytochrome P450 24 (CYP24A1) respectively. Therefore the use of potent and selective inhibitors of CYP26A1 and CYP24A1 with ATRA and la,25-(OH)2-D3 respectively may represent a new strategy for the treatment of cancer. The pharmacophore model of CYP26A1 inhibitors was constructed using MOE software. A database of 71 inhibitors with different conformations have been built and arranged according to activity. The resulting pharmacophore model has 8 features of which 5 features are essential to get the CYP26A1 inhibitory activity. The designed model was used to build new inhibitors, which have reasonable activity. Two series were synthesised for CYP26A1 inhibition. The first series was designed to investigate the effect of changing the structure of the lead compound on the inhibitory activity against CYP26A1 and was depending mainly on presence of imidazole moiety, and the second series was a result of the pharmacophore search and was mainly oxadiazole derivatives. These two series were biologically evaluated using a MCF-7 breast cancer cell assay previously described by our group and also some of the compounds were tested in the biochemical assay. Changing of the structure could be tolerated to a certain limit as long as the imidazole ring is included which is the main part responsible for the binding with the haem in CYP26A1 enzyme. Some of the resulting compounds has good activity, specially methyl anti-3-(1H-1-imidazolyl)-3-[4-(phenylamino)phenyl]-2-methylpropanoate which should IC50 of 26 nM in the biochemical CYP26A1 assay. The oxadiazole derivatives did not show very good activity against CYP26A1 cell based assay, may be owing to the decrease in the flexibility of the molecules. Further investigation in the first series, i.e. the imidazole containing compounds, is being continued in our group. As for CYP24A1 inhibition, two series; the azoles and the tetralones, were synthesised and biologically evaluated. The tetralones do not seem to have a very good activity against CYP24A1, as the most active compound, which is 2-[l-(2-ethylphenyl)methylidene]-6-methoxy-1,2,3,4-tetrahydro-1-naphthalenone showed IC50 of 1.92 pM which about 4 folds less potent than ketoconazole (IC50 = 0.52 pM). As for the azoles, it seems that the azoles would be much more active than the tetralone derivatives as N-[2-( 1H-1 -imidazolyl)-2-phenylethyl]-4-[(£)-2-phenyl-1 -ethenyl] benzamide displayed greater inhibitory activity (IC50 = 0.3 pM) than the standard ketoconazole (IC50 = 0.52 pM). As a result of this work, it seems that the azole type of these compounds could be of interest for future development

Robustness of Firm-Specific and Macroeconomic Determinants of Exploration Investments: Implications from Egyptian Oil & Gas Industry

The uncertainty that surrounds Oil and Gas exploration environments call for an examination at different angles. In terms of robustness, this study focuses on three performance measurements: (a) the amount of exploration investments, (b) the growth rate of exploration investments and (c) the Value at Risk (VaR) of exploration investments.The study utilizes the properties of discriminant analysis for deriving Z-score models that can be used for monitoring firms\u27 performance. A co-integration analysis is utilized as well in order to examine the level of co-integration between predictors of each performance measure. The sample includes annual data for forty one firms (local and multinational) working in the Oil and Gas industry in Egypt for the period 2009-2014.The results show that (a) amount and growth of exploration investment are quite robust performance measures in the Oil and Gas industry, (b) VaR of exploration investment is sporadic as it firm-specific, (c) GDP, Capital expenditure and operating expenditure are quite relevant for managing and monitoring growth of exploration investments.The study offers robust evidence that amount and growth of exploration investment are quire relevant firm performance in the Oil and Gas Industry

Antioxidant Role of Vitamin C in Alleviating the Reproductive Toxicity of Lead Acetate in Male Rats

Environmental pollution with heavy metals represents global problem. One of these heavy metals is the lead acetate that emits from many industries such as paint, ceramics, lead containing pipes and plastics led to a manifold rise in the occurrence of free lead in biological systems and the environment. Exposure to lead acetate affects most of the body’s organs especially testes since it has a unique vascular system. Therefore, the present study aimed to evaluate the protective effect of vitamin C against lead acetate induced testicular toxicity in rats. Thirty male adult albino rats were used in this study. They were equally divided into three groups; group I "control group", group II "lead acetate treated group" and group III "lead acetate and vitamin C treated group". Administration of lead acetate (20 mg /kg body weight for 8 successive weeks) resulted in a significant decrease in serum level of testosterone. It also led to a significant increase in the testicular tissue homogenate concentration of MDA and a significant decrease in GSH concentration and catalase activity. Administration of vitamin C (20 mg/kg body weight) with lead acetate for 8 successive weeks succeeded in improving semen quality and antioxidant enzyme concentrations of testes. It can be concluded that lead acetate testicular toxicity in rats led to disturbance in serum level of the main male reproductive hormone and increased testicular contents of oxidative markers and decreased the antioxidant markers. The use of vitamin C improved these changes.  &nbsp