Polarity Of Medium Research Articles

Biodegradable and active zein-gelatin-based electrospun mats and solvent-cast films incorporating sage extract: Formulation and comparative characterization

This study aimed to develop active, biodegradable materials for food packaging by incorporating sage extract (SE) within a zein-gelatin blend by electrospinning and solvent casting. The fabrication techniques, SE incorporation, and its content (5, 10% w/w) determined the materials’ properties. Electrospinning produced 0.36–0.53 mm thick, non-transparent fibrous mats (mean fiber diameter 1.12–1.36 µm). Solvent casting generated 0.34–0.41 mm thick, transparent continuous films. The analysis indicated the constituents’ compatibility, homogenous dispersion, and efficient SE incorporation without strong chemical interactions and phase separation. The solvent-cast films presented more ordered structures, higher mechanical resistance, elongation, and water vapor barrier performance than the electrospun mats. The SE-incorporating formulations showed phenolics’ delivery ability to food simulants influenced by structure, SE content, and media polarity. The electrospun mats expressed higher DPPH• radicals’ inhibition, while the solvent-cast films showed stronger Staphylococcus aureus and Escherichia coli growth inhibition, increased by SE incorporation. All formulations showed rapid complete bio-disintegration in compost (18–25 days).

Befriended to polarise? The impact of friend identity on review polarisation—A quasi‐experiment

AbstractOpinion polarisation in social media has recently become a significant issue. The existing literature mainly attributes polarisation to online friends' informational social influence, that is, users are more likely to interact with others with similar opinions, which leads to the echo chamber effect. However, the impact of social interaction on individual polarisation may also result from normative social influence, which varies with social settings on the platform. In this paper, we leverage a quasi‐experiment to investigate the normative social influence of online friends on focal users' review polarity. We use fixed effects and difference‐in‐differences approaches, along with propensity score matching, to address the potential endogeneity in users' friend function adoption decisions. Our results indicate that adopting the friend function leads users to post less extreme ratings. We further separate the reviews into positive and negative, finding that the reduction in the review polarity for positive reviews is more prominent than for negative ones. Regarding user heterogeneity, our causal forest analysis uncovers that users with a higher engagement level on the platform are less affected by adopting the friend function than those with less engagement. Our study has clear implications for managers and platform designers, highlighting the importance of social function design in reducing social media induced polarisation.

Introduction to Freedom of Expression in an Age of Social Media, Misinformation, and Political Polarization

Introduction to Freedom of Expression in an Age of Social Media, Misinformation, and Political Polarization

Research and Selection of Sorbents for Volatile Organic Compounds (VOC) Sampling Tubes

Volatile organic compounds (VOCs) are common emitting substances in vehicle interior parts and materials, with a wide range of boiling points (50-250°C) and a polarity range ranging from medium to non-polar, at least 200 species. Currently, VOC sampling mainly uses Tenax TA sorbent for collection, which has good stability and is suitable for weakly polar to non-polar substances between C6-C16. But there are many types of VOC substances, and each substance has its unique characteristics. Tenax TA is not suitable for all substances, and it is not the best sorbent choice for substances with medium polarity or low carbon number. In recent years, the vehicle and indoor environmental standards are open to the selection of sorbent, no longer limiting the type of sorbent sorbent, and more sampling tubes mixed with different sorbent types have emerged to achieve the best sampling results. After summarizing the common emitted substances in the car, this article selects 6 common types of sorbents or mixed sorbents for substance collection, and searches for the optimal sorbent type for each substance.

Populism, democratic participation, and media polarization in the digital age: The case of vaccine hesitancy in Greece

Populism, democratic participation, and media polarization in the digital age: The case of vaccine hesitancy in Greece

Распространение поперечных волн с вертикальной и горизонтальной поляризацией в слоистой среде с неоднородными граничными условиями

The paper investigates the propagation of a transverse wave of vertical and horizontal polarization in a layered medium with inhomogeneous boundary conditions for two variants of the geometry of wave propagation relative to the layers of the structure: parallel and perpendicular to the layers. Dispersion equations for a transverse wave are derived for the cases of propagation under consideration. The dispersion equations found with respect to the wave number are solved to find the dependences of the effective velocities of the transverse wave of vertical and horizontal polarization on the relative thickness of the layer and the parameters of the materials. The obtained dependences are used in the problems of finding the physical and mechanical characteristics of the medium on the basis of acoustic measurements.

A Free Speech-Based Response to Media Polarization

A Free Speech-Based Response to Media Polarization

Framing of poverty in TV reporting in Serbia

The paper analyzes how poverty is presented in the television discourse in Serbia. The theoretical-methodological framework of research relies on quantitative-qualitative content analysis and the concept of media framing in which the usage of patterns of selection, emphasis and exclusion result in the interpretation and assessment of certain events. The sample for analysis consisted of 35 central news programs broadcasted on five television stations on seven cyclically selected days in the period from 10 th October to 27 th October 2021. The goal of the research was to determine the dominant frames of the representation of poverty and to examine whether and to what extent used frames differ in comparison to the previous research. The results show that television framing of poverty is consistent with the general pattern of problematic media polarization in Serbia. Two frames are dominantly represented: general economic poverty and propaganda-populist frame. In the case of the first one, poverty is presented as a background theme in analytic reports on the political and macroeconomic issues. It is reduced to an impersonal approach that does not have the strength to indicate the seriousness of the multidimensional problem of poverty. The second frame is characterized by a blurred picture of poverty. It is distributed through reports on the promotional activities of the president ? the opening of factories and road infrastructure and explains the increasingly pronounced mutual connection between the ruling elite and journalists in the use of demagoga and propaganda matrices in conveying and setting frames as generally acceptable.

Impact of crude oil properties on stability of HCl-crude oil emulsion using XDLVO theory

Undesired emulsification of HCl-crude oils during acid jobs may compromise oil production due to clogging of near wellbore region. This may be resulted from the presence of natural surfactants such as asphaltene. In this paper, the relation between some of crude oil properties including API gravity, dynamic viscosity, polarity, total base number (TBN) with the emulsion stability has been studied by applying the XDLVO theory. The results showed that TBN, and polarity of the crude oil medium can be manifested as reliable criteria for predicting the emulsion stability, while the impact of API gravity and dynamic viscosity of the crude oil were marginal. Sensitivity analyses were also carried out to discern the most dominant parameters on the total interaction energy between droplets in the HCl-crude oil emulsions. It was found that in short distances between droplets, the effect of electron acceptor/donor components are important in such a way that a crude oil with high electron donor and low electron acceptor components would form more stable emulsion when it is mixed with the HCl solution, while no noticeable effect was observed for longer distances. In addition, the results of adhesion tests showed that the presence of HCl solution increases the adhesion of different crude oils onto a glass surface. This is imperative for evaluating the extent of formation damage due to acid-crude oil emulsion and acid sludge formation, when they stick to the rock surfaces. These findings can serve as guideline for choosing the appropriate acid stimulation job in connection with crude oil properties for management of formation damage.

Correlation of Light Polarization in the Magnetic Media with Non-Spherical Point-Like Inclusions

Light propagation through magnetic media with ellipsoidal inclusions much smaller than the light wavelength was investigated theoretically. It is assumed that the ellipsoidal inclusions have the same orientation but are randomly distributed inside the magnetic medium by the Gaussian law. The theoretical model is based on the multiple-scattering theory in the ladder approximation. A new type of electromagnetic field correlation is found to appear in this case, while it is absent in isotropic magnetic nanocomposites and nonmagnetic anisotropic composites. This feature allows for the precise control of light polarization in anisotropic magnetic media.

Control of Fluorescence of Organic Dyes in the Solid-State by Supramolecular Interactions.

Fluorescent organic dyes play an essential role in the creation of new "smart" materials. Fragments and functional groups capable of free rotation around single bonds can significantly change the fluorescent organic dye's electronic structure under analyte effects, phase state transitions, or changes in temperature, pressure, and media polarity. Dependencies between steric and electronic structures become highly important in transition from a solution to a solid-state. Such transitions are accompanied by a significant increase in the dye molecular structure's rigidity due to supramolecular associates' formation such as H-bonding, π···π and dipole-dipole interactions. Among those supramolecular effects, H-bonding interactions, first of all, lead to significant molecular packing changes between loose or rigid structures, thus affecting the fluorescent dye's electronic states' energy and configuration, its fluorescent signal's position and intensity. All the functional groups and heteroatoms that are met in the organic dyes seem to be involved in the control of fluorescence via H-bonding: C-H···N, C-H···π, S = O···H-C, P = O···H, C-H···O, NH···N, C - H···C, C - H···Se, N-H···O, C - H···F, C-F···H. Effects of molecular packing of fluorescent organic dyes are successfully used in developing mechano-, piezo-, thermo- fluorochromes materials for their applications in the optical recording of information, sensors, security items, memory elements, organic light-emitting diodes (OLEDs) technologies.

The Effects of Social Media, Elites, and Political Polarization on Civil Conflict

Although prior research has investigated how social, economic, and political factors affect civil conflict, empirical scholarship has yet to consider how social media impacts civil conflict. Using cross-national research for up to 157 states from 2000–2019, this study examines the effect social media has on civil conflict. We find that more time spent on social media, greater social media penetration (i.e. the number of users), and the specific manner elites use social media are associated with an increased number and severity of civil conflicts. We also carry out mediation analysis and see that elite use of social media to organize offline political activities, government elites’ dissemination of false information, and political party elites’ dissemination of disinformation are all correlated with an increase in political polarization, and polarization raises the likelihood of civil conflict. Our results indicate the ways social media affects political violence, showing how different communication technologies can serve to exacerbate civil conflict under certain conditions.

Synthesis and Solvent Dependent Fluorescence of 4-Amino naphthalene-1-sulfonic acid (AmNS)-Alginate (ALG) Bacterial Polymer

4-Amino naphthalene-1-sulfonic acid-alginate (AmNS-ALG) bacterial polymer flakes were synthesized and their spectroscopic properties were investigated. The solvatochromic behavior of the fluorescent polymer was monitored in solvents of diverse polarity using the excitation and emission fluorescence spectra combined with fluorescence lifetime measurements. The AmNS-ALG exhibited a positive solvatochromism with regard to the change of solvent polarity from high polar (water) to low polar (butanol). The excitation and emission intensities of AmNS-ALG increased markedly in water compared with alcoholic solvents. Measuring the quantum yield indicated that the highest values of quantum efficiency were obtained in more polar solvents. For AmNS-ALG in water and butanol, the greatest lifetime value was reduced from 11 to 7 ns. The obtained spectroscopic data suggest that the AmNS-ALG could be used as a medium polarity sensor.

Shear viscosity in two-dimensional dipole systems.

The results of modeling shear flows in classical two-dimensional (2D) dipole systems are presented. We used the method of nonequilibrium molecular dynamics to calculate the viscosity at various shear rates. The coefficients of shear viscosity are given in the limit of low shear rates for various regimes of interparticle correlation from a weakly correlated gaseous state to a strongly nonideal liquid state near the crystallization point. The calculations were carried out for bare (unscreened) dipole systems, as well as for dipole systems in a polarizable medium that provide screening of the dipole-dipole interaction. The effect of shear thinning in 2D dipole systems is reported for low values of the coupling parameter. In addition, it is shown that dipole systems can become both less and more viscous due to the presence of a screening medium, depending on the degree of interparticle correlation. The optimal simulation parameters are discussed within the framework of the method of nonequilibrium molecular dynamics for determining the shear viscosity of two-dimensional dipole systems. Moreover, we present a simple fitting curve which provides a universal scaling law for both bare dipole-dipole interaction and screened dipole-dipole interaction.

Polarity-dependent Response of Phytochemical Extraction and Antioxidant Potential of Different Parts of Alcea rosea

Objectives: Alcea rosea is a good source of medicinlly importeant bioactive phytochemical compounds. The complete extraction of these biochemicals from plant material has remained a problem for the researchers and manufacturers. This study was planned to report the medicinal value of A. rosea and find out the suitable extraction solvent to enhance the extraction yield of its phytochemical compounds and their antioxidant potential. Materials and Methods: The powdered samples of the selected parts of A. rosea were extracted in solvents of varying dipole moments (hexane: 0 D, ethyl acetate: 2.8 D, and methanol: 5.1 D). The extracts were screened for the presence of important phytochemicals and analyzed for their phytochemical content and antioxidant potential. Results: The studied parts of A. rosea consisted of flavonoids, tannins, terpenoids, saponins, and cardiac glycosides. The regression analysis showed polarity-dependent significant positive effects (p<0.05) on the extract yield, phenolic content, and antioxidant activity in terms of Trolox equivalent total antioxidant activity, ferric reducing power, and nitrogen free radical scavenging activity of the extracts. However, a mixed response of total flavonoids and total tannins content and hydroxyl radical scavenging activity of the extracts was observed against solvent polarity. Conclusion: A polarity dependent increase in phytochemical content and free radical scavenging capacity was observed. The study suggests that the polar solvents are more suitable to achieve a good extract yield of phytochemicals possessing a strong antioxidant ability and the solvents of medium polarity may be suitable for the extraction of flavonoids and tannins from the studied parts of A. rosea.

New substances of Equisetum hyemale L. extracts and their in vivo antitumoral effect against oral squamous cell carcinoma

Ethnobotanical relevanceEquisetum hyemale is used in traditional medicine as an anti-inflammatory, antioxidant, diuretic and anticancer agent. Recent studies have observed antiproliferative activity of this species in some tumor cell lines. Aim of the studyThe aim of this study was to evaluate the antiproliferative activity of the ethanol extract of E. hyemale and its partitions in oral squamous carcinoma cell lines, the death pathways induced by the most active partition, the acute toxicity and therapeutic activity, and the identification of the main compounds. Materials and methodsThe ethanol crude extract was prepared from the stems of E. hyemale and partitions were obtained from this extract with n-hexane, dichloromethane and ethyl acetate. Cytotoxicity assays were performed using MTT on human oral tumor lines SCC-9, SCC4 and SCC-25, and normal primary fibroblasts. The main pathways of programmed cell death were analyzed. Acute toxicity in mice was performed using the most active partition, ethyl acetate. Antitumor activity was accessed in xenotransplants grafts of SCC-9 cells in Balb/nude mice. Phytochemical analysis was performed using UHPLC-MS/MS and dereplication was done using Global Natural Product Social Molecular Networking (GNPS) analysis. ResultsEthanol extract, n-hexane and ethyl acetate partitions showed dose-dependent activity and selectivity towards oral tumor cells, with the ethyl acetate being the most bioactive. This medium polarity partition was shown to induce tumor cell death through apoptosis due to the presence of activated caspase 3/7, DNA fragmentation, chromatin condensation and phosphatidylserine exposure. The ethyl acetate partition also produced low toxicity in mice, provoking mild hepatic changes, but without causing necrosis and significantly reduced tumors volume and weight in xenotransplants of SCC-9 cells. Phytochemical analysis allowed identification of kaempferol glycosides and cinnamic acid derivatives previously described for E. hyemale. In addition it was possible to identify 6 new non-glycolyzed flavonoids 5-Hydroxy-3′,4′,7,8-tetramethoxyflavone (14), 5,4′-Dihydroxy-7,8,3′-trimethoxyflavone (15), 5,7-Dihydroxy-3′,4′-dimethoxyflavone (16), 3′,4,5,7-Tretramethoxyflavone (17), 5-Hydroxy-3′4′,7-trimethoxyflavone (18), and 5,4′-Dihydroxy-3′-7′-dimethoxyflavone (19); besides 5 compounds already determined to be cytotoxic in other species, Isoferulic acid (1), Ferulic acid (2), Atractylenolide III (6), Dihydroxy-3′,4′-dimethoxyflavone (16), and 5-Hydroxy-3′4 ′,7-trimethoxyflavone (18). ConclusionThe results indicate that the E. hyemale extract and partitions inhibited 3 different cell lines of OSCC in a highly selective nontoxic way by inducing apoptosis of the cells. We identified 6 new non-glycosylated flavonoids and 5 other substances in this species.

Balancing Panchromatic Absorption and Multistep Charge Separation in a Compact Molecular Architecture

A panchromatic triad and a charge-separation unit are joined in a crossbar architecture to capture solar energy. The panchromatic-absorber triad (T) is comprised of a central free-base porphyrin that is strongly coupled via direct ethyne linkages to two perylene-monoimide (PMI) groups. The charge-separation unit incorporates a free-base or zinc chlorin (C or ZnC) as a hole acceptor (or electron donor) and a perylene-diimide (PDI) as an electron acceptor, both attached to the porphyrin via diphenylethyne linkers. The free-base porphyrin is common to both light-harvesting and charge-separation motifs. The chlorin and PDI also function as ancillary light absorbers, complementing direct excitation of the panchromatic triad to produce the discrete lowest excited state of the array (T*). Attainment of full charge separation across the pentad entails two steps: (1) an initial excited-state hole/electron-transfer process to oxidize the chlorin (and reduce the panchromatic triad) or reduce the PDI (and oxidize the panchromatic triad); and (2) subsequent ground-state electron/hole migration to produce oxidized chlorin and reduced PDI. Full charge separation for pentad ZnC-T-PDI to generate ZnC+-T-PDI- occurs with a quantum yield of ∼30% and mean lifetime ∼1 μs in dimethyl sulfoxide. For C-T-PDI, initial charge separation is followed by rapid charge recombination. The molecular designs and studies reported here reveal the challenges of balancing the demands for charge separation (linker length and composition, excited-state energies, redox potentials, and medium polarity) with the constraints for panchromatic absorption (strong electronic coupling of the porphyrin and two PMI units) for integrated function in solar-energy conversion.

Chromatographic Separation of Aromatic Amine Isomers: A Solved Issue by a New Amphiphilic Pillar[6]arene Stationary Phase.

In this work, the fabrication, synthesis, and characterization of a new stationary phase based on an amphiphilic pillar[6]arene (P6A-C10-2NH2) for gas chromatographic analyses are reported. The gas chromatography (GC) column prepared with P6A-C10-2NH2 stationary phase exhibited a medium polarity, an efficiency of 3219 plates/m, and unmatched resolving capabilities toward chloroaniline, bromoaniline, iodoaniline, and toluidine isomers. Furthermore, the P6A-C10-2NH2 column showed excellent repeatability with maximum relative standard deviations equal to 0.02, 0.07, and 2.56% for run-to-run, day-to-day, and column-to-column, respectively, demonstrating a great potential as a new stationary phase in separation science.

Design and Self-Assembly of Polyhedron Particles to Construct Iridescent Structural Colors.

Polyhedron particles exhibit unique physical properties in constructing novel materials. Here, the polystyrene (PS) polyhedron particles were fabricated via dispersion polymerization, and their morphologies can be controlled by tuning the divinylbenzene (DVB) content and polarity of the reaction medium. The possible formation mechanism is the asymmetric distribution of cross-linked networks during the phase separation process. In addition, the large-scale iridescent structural colors based on polyhedrons were obtained and further explored their applications in smart displays. This presented method guides the fabrication of anisotropic particles and their further assembly to construct novel materials.

Network activated frames: content sharing and perceived polarization in social media

Abstract Our article describes how users’ decisions to share content alter the frequencies of the frame elements observed by social media peers. Changes in the frequency of distinct frame elements shape how individuals interpret, classify and define situations and events. We label this process Network Activated Frames (NAFs). We test the mechanisms behind NAF with an original image-based conjoint design that replicates network activation in three surveys. Results show that partisans share more content than nonpartisans and that their preferences differ from those of nonpartisans. Our findings show that a network of peers with cross-cutting ideological preferences may be perceived as a bubble if partisans amplify content they like at higher rates. Beginning with fully randomized probabilities, the output from our experiments is more extreme than the preferences of the median users, as partisans activate more and different frame elements than nonpartisans. We implement the experiments in Argentina, Brazil, and Mexico.