scholarly journals Interactions Between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation

2021 ◽  
Author(s):  
Patrizio Raffa
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Interaction Model ◽  
Industrial Applications ◽  
Molecular Organization ◽  
Different Types ◽  
Solution Rheology ◽  
Interesting Class ◽  
First Time

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of same charge or nonionic surfactants, while the opposite charge surfactant cause precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

scholarly journals Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1729
Author(s):  
Patrizio Raffa
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Interaction Model ◽  
Industrial Applications ◽  
Molecular Organization ◽  
Different Types ◽  
Solution Rheology ◽  
Interesting Class ◽  
First Time

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

scholarly journals MiRNA Expression in Neuroendocrine Neoplasms of Frequent Localizations

2021 ◽  
Vol 7 (3) ◽  
pp. 38
Author(s):  
Alexandra Korotaeva ◽  
Danzan Mansorunov ◽  
Natalya Apanovich ◽  
Anna Kuzevanova ◽  
Alexander Karpukhin
Keyword(s):  
Mirna Expression ◽  
Malignant Tumors ◽  
Neuroendocrine Neoplasms ◽  
Specific Expression ◽  
Clinical Biomarkers ◽  
Different Types ◽  
Functional Features ◽  
First Time ◽  
Potential Biomarkers

Neuroendocrine neoplasms (NEN) are infrequent malignant tumors of a neuroendocrine nature that arise in various organs. They occur most frequently in the lungs, intestines, stomach and pancreas. Molecular diagnostics and prognosis of NEN development are highly relevant. The role of clinical biomarkers can be played by microRNAs (miRNAs). This work is devoted to the analysis of data on miRNA expression in NENs. For the first time, a search for specificity or a community of their functional characteristics in different types of NEN was carried out. Their properties as biomarkers were also analyzed. To date, more than 100 miRNAs have been characterized as differentially expressed and significant for the development of NEN tumors. Only about 10% of the studied miRNAs are expressed in several types of NEN; differential expression of the remaining 90% was found only in tumors of specific localizations. A significant number of miRNAs have been identified as potential biomarkers. However, only a few miRNAs have values that characterized their quality as markers. The analysis demonstrates the predominant specific expression of miRNA in each studied type of NEN. This indicates that miRNA’s functional features are predominantly influenced by the tissue in which they are formed.

scholarly journals Morphometric characterization of fibrinogen's αC regions and their role in fibrin self-assembly and molecular organization

Nanoscale ◽  
2017 ◽  
Vol 9 (36) ◽  
pp. 13707-13716 ◽  
Author(s):  
Anna D. Protopopova ◽  
Rustem I. Litvinov ◽  
Dennis K. Galanakis ◽  
Chandrasekaran Nagaswami ◽  
Nikolay A. Barinov ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Molecular Organization ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Atomic Force Microscopy Imaging ◽  
Morphometric Characterization

High-resolution atomic force microscopy imaging reveals the role of fibrinogen αC regions in the early stages of fibrin self-assembly.

Long-term unemployment

2020 ◽  
Vol 47 (4) ◽  
pp. 713-727
Author(s):  
Emmanuel Apergis ◽  
Nicholas Apergis
Keyword(s):  
Working Environment ◽  
Employment Relations ◽  
Content Type ◽  
Different Types ◽  
The Uk ◽  
First Time ◽  
Robustness Check ◽  
Modelling Approach

PurposeThis paper empirically explores the role of skill losses during unemployment behind firms' behaviour in interviewing long-term unemployedDesign/methodology/approachThe analysis makes use of the Work Employment Relations Survey in the UK, while it applies a panel probit modelling approach to estimate the empirical findings.FindingsThe findings document that skill losses during long-term unemployment reduce the likelihood of an interview, while they emphasize the need for certain policies that could compensate for this deterioration of skills. For robustness check, the estimation strategy survives the examination of the same predictors under different types of the working environment.Originality/valueThe original values of the work 1 combines for the first time both duration and technology as predictors of interview probability. Until now, the independent variables were used to test whether an individual has managed to exit unemployment, thus skipping the step of the interview process.

scholarly journals Synergistic role of nucleotides and lipids for the self-assembly of Shs1 septin oligomers

2020 ◽  
Vol 477 (14) ◽  
pp. 2697-2714
Author(s):  
Cyntia Taveneau ◽  
Rémi Blanc ◽  
Gérard Péhau-Arnaudet ◽  
Aurélie Di Cicco ◽  
Aurélie Bertin
Keyword(s):  
Self Assembly ◽  
Structural Organization ◽  
Electron Tomography ◽  
Budding Yeast ◽  
The Self ◽  
Two Dimensional ◽  
Molecular Polymorphism ◽  
Cryo Electron Tomography ◽  
First Time

Budding yeast septins are essential for cell division and polarity. Septins assemble as palindromic linear octameric complexes. The function and ultra-structural organization of septins are finely governed by their molecular polymorphism. In particular, in budding yeast, the end subunit can stand either as Shs1 or Cdc11. We have dissected, here, for the first time, the behavior of the Shs1 protomer bound to membranes at nanometer resolution, in complex with the other septins. Using electron microscopy, we have shown that on membranes, Shs1 protomers self-assemble into rings, bundles, filaments or two-dimensional gauzes. Using a set of specific mutants we have demonstrated a synergistic role of both nucleotides and lipids for the organization and oligomerization of budding yeast septins. Besides, cryo-electron tomography assays show that vesicles are deformed by the interaction between Shs1 oligomers and lipids. The Shs1–Shs1 interface is stabilized by the presence of phosphoinositides, allowing the visualization of micrometric long filaments formed by Shs1 protomers. In addition, molecular modeling experiments have revealed a potential molecular mechanism regarding the selectivity of septin subunits for phosphoinositide lipids.

scholarly journals Counteraction to Criminality In the Ukrainian SSR In the Second Half of 1930S

2020 ◽  
Keyword(s):  
Methodological Principle ◽  
General Level ◽  
Collective Farm ◽  
Soviet History ◽  
Political Situation ◽  
Different Types ◽  
History Of ◽  
The Republic ◽  
First Time

For today there is a far of the publications sanctified to soviet history of 1930th. However basic attention in them is spared there are 1937-1939 to strengthening of the totalitarian mode and repressions. And the problems of combating crime have received little attention.Research aim. Taking into account insufficient worked out of theme, an author put an aim to itself to light up the role of militia in counteraction to some types of criminality in the second half 1930th. This range of problems is wide enough, that is why we specially did not investigate some of directions of activity of militia at this time, in particular fight against gangsterism, counteract to economic criminality and role of militia in repressions 1937-1938, as it is an object other our scientific researches.Research methodology. The fundamental methodological principle of the study for the author was historicism. We tried to study the processes, events and facts in chronological order, taking into account the then socio-political situation. The method of comparison allowed to consider the general and special in activity of militia of different regions of the republic and differences in counteraction to different types of crimes.The scientific novelty of the article is that for the first time in the historical literature it reveals the activities of the police in combating crime in the second half of the 1930s., related to improving the work of investigators, district inspectors.In the article basic directions of activity of militia are exposed in relation to counteraction to some types of crimes in Ukraine, in the second half of 1930th. In this time a "liberal" period made off relatively in history of soviet legislation.It was considered that in connection from completion of building of socialism in the USSR the main causations of crime, related to the inheritance of, are czarism on the whole removed, and the pore of the most rapid liquidation of criminality came, although at this time appeared and new types of crimes : 1. crimes related to the passport system (imitation, sale and purchase, theft of passports); 2. violation of charter of agricultural artel, violation of soviet and of a collective farm democracy; 3.sabotage of Stakhanovsky motion, pursuit ofStakhanov’ s men.New Constitution of the USSR was accepted in 1936, and in 1937 is new Constitution of Ukraine. For them wide rights for soviet citizens were proclaimed, but in reality they were not realized, becoming illustration to neglect of law and law and order.However would be an overstatement to consider that there was complete legal anarchy and raging of criminality in the state .Conclusions. In the second half 1930th a militia, without regard to mass repressions and certain vagueness of fate of many workers, continued counteraction to criminality. Certain attention was spared to the improvement of work of investigators, district inspectors, secret-service-informative work, bringing in of public to counteraction to criminality. In the total it was succeeded to attain some reduction of general level to criminality.

scholarly journals Extensins: Self-Assembly, Crosslinking, and the Role of Peroxidases

2021 ◽  
Vol 12 ◽  
Author(s):  
John W. Mishler-Elmore ◽  
Yadi Zhou ◽  
Abhijit Sukul ◽  
Mercedes Oblak ◽  
Li Tan ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Self Assembly ◽  
Regulatory Mechanism ◽  
Pathogen Infection ◽  
Cellular Defense ◽  
Covalent Crosslinking ◽  
Different Types ◽  
Intermolecular Crosslinking ◽  
Intermolecular Crosslinks

The extensin (EXT) network is elaborated by the covalent intermolecular crosslinking of EXT glycoprotein monomers, and its proper assembly is important for numerous aspects of basic wall architecture and cellular defense. In this review, we discuss new advances in the secretion of EXT monomers and the molecular drivers of EXT network self-assembly. Many of the functions of EXTs are conferred through covalent crosslinking into the wall, so we also discuss the different types of known intermolecular crosslinks, the enzymes that are involved, as well as the potential for additional crosslinks that are yet to be identified. EXTs also function in wall architecture independent of crosslinking status, and therefore, we explore the role of non-crosslinking EXTs. As EXT crosslinking is upregulated in response to wounding and pathogen infection, we discuss a potential regulatory mechanism to control covalent crosslinking and its relationship to the subcellular localization of the crosslinking enzymes.

Modification of molecular organization of polymers by gas sorption: Thermodynamic aspects and industrial applications

2009 ◽  
Vol 81 (9) ◽  
pp. 1603-1614 ◽  
Author(s):  
Séverine A. E. Boyer ◽  
Takeshi Yamada ◽  
Hirohisa Yoshida ◽  
Jean-Pierre E. Grolier
Keyword(s):  
Industrial Applications ◽  
Molecular Organization ◽  
Polymer Science ◽  
Gas Sorption ◽  
Nanoscale Structures ◽  
Self Assembling ◽  
Polymer Foaming ◽  
Thermodynamic Conditions ◽  
Set Up

In polymer science, gas–polymer interactions play a central role for the development of new polymeric structures for specific applications. This is typically the case for polymer foaming and for self-assembling of nanoscale structures where the nature of the gas and the thermodynamic conditions are essential to control. An important applied field where gas sorption in polymers has to be documented through intensive investigations concerns the (non)-controlled solubilization of light gases in the polymers serving, for example, in the oil industry for the transport of petroleum fluids. An experimental set-up coupling a vibrating-wire (VW) detector and a pVT technique has been used to simultaneously evaluate the amount of gas entering a polymer under controlled temperature and pressure and the concomitant swelling of the polymer. Scanning transitiometry has been used to determine the interaction energy during gas sorption in different polymers; the technique was also used to determine the thermophysical properties of polymers submitted to gas sorption. The role of the pressurizing fluid has been documented in terms of the influence of pressure, temperature, and nature of the fluid.

scholarly journals Lichens—A Potential Source for Nanoparticles Fabrication: A Review on Nanoparticles Biosynthesis and Their Prospective Applications

2021 ◽  
Vol 7 (4) ◽  
pp. 291
Author(s):  
Reham Samir Hamida ◽  
Mohamed Abdelaal Ali ◽  
Nabila Elsayed Abdelmeguid ◽  
Mayasar Ibrahim Al-Zaban ◽  
Lina Baz ◽  
...  
Keyword(s):  
Low Cost ◽  
Antimicrobial Activities ◽  
Synthesis Process ◽  
Biological Synthesis ◽  
Synthesis Of Nanoparticles ◽  
Different Types ◽  
Target Metal ◽  
First Time ◽  
Synthesis Of Nanomaterials

Green synthesis of nanoparticles (NPs) is a safe, eco-friendly, and relatively inexpensive alternative to conventional routes of NPs production. These methods require natural resources such as cyanobacteria, algae, plants, fungi, lichens, and naturally extracted biomolecules such as pigments, vitamins, polysaccharides, proteins, and enzymes to reduce bulk materials (the target metal salts) into a nanoscale product. Synthesis of nanomaterials (NMs) using lichen extracts is a promising eco-friendly, simple, low-cost biological synthesis process. Lichens are groups of organisms including multiple types of fungi and algae that live in symbiosis. Until now, the fabrication of NPs using lichens has remained largely unexplored, although the role of lichens as natural factories for synthesizing NPs has been reported. Lichens have a potential reducible activity to fabricate different types of NMs, including metal and metal oxide NPs and bimetallic alloys and nanocomposites. These NPs exhibit promising catalytic and antidiabetic, antioxidant, and antimicrobial activities. To the best of our knowledge, this review provides, for the first time, an overview of the main published studies concerning the use of lichen for nanofabrication and the applications of these NMs in different sectors. Moreover, the possible mechanisms of biosynthesis are discussed, together with the various optimization factors influencing the biological synthesis and toxicity of NPs.

Potential Uses of Vinegar as a Medicine and Related in vivo Mechanisms

2016 ◽  
Vol 86 (3-4) ◽  
pp. 127-151 ◽  
Author(s):  
Zeshan Ali ◽  
Zhenbin Wang ◽  
Rai Muhammad Amir ◽  
Shoaib Younas ◽  
Asif Wali ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Review Paper ◽  
Heart Diseases ◽  
Folk Medicine ◽  
Active Role ◽  
Current Review ◽  
Different Types ◽  
Positive Effect

While the use of vinegar to fi ght against infections and other crucial conditions dates back to Hippocrates, recent research has found that vinegar consumption has a positive effect on biomarkers for diabetes, cancer, and heart diseases. Different types of vinegar have been used in the world during different time periods. Vinegar is produced by a fermentation process. Foods with a high content of carbohydrates are a good source of vinegar. Review of the results of different studies performed on vinegar components reveals that the daily use of these components has a healthy impact on the physiological and chemical structure of the human body. During the era of Hippocrates, people used vinegar as a medicine to treat wounds, which means that vinegar is one of the ancient foods used as folk medicine. The purpose of the current review paper is to provide a detailed summary of the outcome of previous studies emphasizing the role of vinegar in treatment of different diseases both in acute and chronic conditions, its in vivo mechanism and the active role of different bacteria.

Sign in / Sign up

Export Citation Format

Share Document