Polar Part Research Articles

Latituditual Structure of Dayside Polar Cusp Precipitation

The results of observations of low-altitude spacecraft crossing the daytime sector of the auroral zone and of high-apogee spacecraft in the equatorial plane of the magnetosphere were analyzed in order to identify the main processes leading to the formation of dayside polar cusps. Observations from the DMSP F7 spacecraft were used to analyze the latitudinal characteristics of ion precipitation in the cusp region and to study the latitudinal profile of ion pressure in the cusp depending on the IMF parameters. A significant difference was found in identifying the cusp boundaries using an automated data processing system and direct analysis of spacecraft observations. It is shown that for small negative values of the Bz-component of the IMF (〈Bz〉 = –3.0 nT), an ordinary feature of the cusp is the latitudinal profile of the ion pressure (Pi) with a width of ~1° of latitude with two maxima, one of which is located in the equatorward and the other in the poleward of the cusp. For large negative Bz values (–6, –8 nT), the polar maximum in the latitudinal profile Pi disappears; only the equatorial maximum remains, the Pi level at the maximum increases, and the width of the cusp decreases to ~0.7°. For Bz IMF 0, the most characteristic is the Pi profile with a maximum ion pressure in the polar part of the cusp. The cusp for Bz 0 is located at higher latitudes than for Bz 0, and its average latitudinal width increase to ~1.4° of latitude. In the prenoon sector MLT, the most typical for periods with a large negative By-component of the IMF (〈By〉 = –6.3 nT, 〈Bz〉 = –1.7 nT) is a cusp with a width of ~1.4° of latitude with a flat top in the latitudinal Pi profile. Comparison of the pressure distributions observed at low heights with data from high-apogee satellites confirmed the possibility of describing the formation of the cusp as a diamagnetic cavity and using observations in the cusp to determine the ion pressure in the magnetosheath.

Dirac particles with screened Kratzer–Hulthen plus ring-shaped potential in noncompact extra dimensions

To describe the four fundamental interactions observed in the universe, we used the Dirac equation containing an interaction of the screened Kratzer and the Hulthen potential with a ring-shaped term. We study the energy spectra of spin-[Formula: see text] particles in noncompact extra dimensions. The polar and angular parts of the N-dimensional Dirac equation are solved using the Nikiforov–Uvarov method. The transcendental energy equation and the associated two components spinor wavefunctions of the spin-[Formula: see text] particles are obtained. Moreover, we obtained the nonrelativistic limit of our results by mean of a specific mapping. Some special cases of the proposed potential have been discussed, and their corresponding eigenvalue energies were determined. Finally, we proposed that our results can be used in many branches of physics, to investigate scenarios in extra dimensions where spin-[Formula: see text] particles are involved. To test the reliability of our model, we computed the numerical values of the energy spectra of lithium hydride and hydrogen chloride diatomic molecules using a special case of the proposed potential. The energy spectra are calculated for different quantum numbers [Formula: see text] at different values of the dimensionality of the space. The results of this research are overall in good agreement with the theoretical studies of similar investigation.

STRUCTURING OF AN AQUEOUS SUSPENSION OF A SULFUR-GYPSUM MIXTURE IN THE PRESENCE OF A COMPOSITION OF SURFACTANTS AND WATER-SOLUBLE POLYMERS

In this article, the methods of colloidal chemistry show the ways of using accumulated sulfur in oil production and the possibility of structuring a mixture of sulfur with gypsum in the presence of surfactants and polymer complexes. Compositions consisting of anionic polyelectrolyte (NaKMC) and cationic (CTAB), cationic polyelectrolyte (PDMDAAH) and anionic sulfanol surfactant were prepared, their effect on the surface tension of water, ζ-potential and the effect of polymer and surfactant on sulfur were studied. It was found that with an increase in the relative concentration of the polymer-surfactant composition, the plastic strength of the suspension increases, and after a certain time the strength decreases. This is explained by the fact that when the polar part of the surfactant is added to the polar part of the polymer, the polymer becomes hydrophobic, is better adsorbed on sulfur particles, and the strength of the entire system increases. And when all the polar parts of the polymer are neutralized by the polar parts of the surfactant, the surfactant molecules begin to adsorb on the polymer with their hydrophobic part. As a result, the polymer begins to shrink and form a globule. In this case, the plastic strength of the system decreases.

Impact of the Solar Activity on the Propagation of ICMEs: Simulations of Hydro, Magnetic and Median ICMEs at the Minimum and Maximum of Activity

The propagation of interplanetary coronal mass ejections (ICMEs) in the heliosphere is influenced by many physical phenomena, related to the internal structure of the ICME and its interaction with the ambient solar wind and magnetic field. As the solar magnetic field is modulated by the 11 yr dynamo cycle, our goal is to perform a theoretical exploratory study to assess the difference of propagation of an ICME in typical minimum and maximum activity backgrounds. We define a median representative CME at 0.1 au, using both observations and numerical simulations, and describe it using a spheromak model. We use the heliospheric propagator EUropean Heliospheric FORecasting Information Asset to inject the same ICME in two different background wind environments. We then study how the environment and the internal CME structure impact the propagation of the ICME toward Earth, by comparison with an unmagnetized CME. At minimum of activity, the structure of the heliosphere around the ecliptic causes the ICME to slow down, creating a delay with the polar parts of the ejecta. This delay is more important if the ICME is faster. At maximum of activity, a southern coronal hole causes a northward deflection. For these cases, we always find that the ICME at the maximum of activity arrives first, while the ICME at the minimum of activity is actually more geoeffective. The sign of the helicity of the ICME is also a crucial parameter, but at the minimum of activity only, since it affects the magnetic profile and the arrival time up to 8 hr.

Study of aqueous solutions of poloxamers by rotational viscometry and spin probe method

The aim. To study aqueous solutions of different poloxamers by spin probe method and rotational viscometry depending on the temperature and poloxamer content.
 Materials and methods. The aqueous solutions of poloxamers 188, 237, 338 and 407 were studied. The solutions were studied by rotational viscometry at different temperatures; the flow behaviour, yield stress (t0), and dynamic or apparent viscosity (η) were determined. Five spin probes differing in molecular structure, solubility, and radical localisation were introduced into the solutions. Electron paramagnetic resonance (EPR) spectra were obtained. The EPR spectra were used to determine their type and to calculate parameters.
 Results. Three factors are important for gel formation: the poloxamer type, its concentration in aqueous solution, and temperature. As the temperature of aqueous solutions of poloxamers 237, 338, and 407 increases, the rotational correlation times of fatty acid-based spin probes and the order parameters of their EPR spectra decrease. This indicates a decrease in the packing density and orderliness of the polypropylene oxide (PPO) chains in the non-polar part of the poloxamer associates, leading to an increase in the volume fraction of micelles/mesophases and promoting the formation of gels. As the temperature decreases, the opposite processes occur, leading to a gel → sol transition. At 37 °C, non-polar micelle cores could be characterised as two-dimensionally liquid and one-dimensionally solid. The rotational correlation times of the hydrophilic spin probe 4-OXO-TEMPO in 25 % aqueous solutions of poloxamers 338 and 407 are approximately constant or increasing despite an increase in the temperature. This indicates that in the polar part of the poloxamer associates, where this probe is partially localised, structural rearrangements occur with increasing temperature, which probably prevents hydrophobic hydration of the PPO chains.
 Conclusions. The rheological properties of aqueous solutions of poloxamers depend on their type, concentration, and temperature. According to the parameters of the EPR spectra of fatty acid-based spin probes, it was found that with increasing temperature, the packing density and the orderliness of the PPO chains in the non-polar part of the poloxamer associates decrease, probably leading to an increase in the volume of the micelles and causing a sol → gel transition

Investigation of the Chemical Durability and Thermal Impact on Functional Coated Surfaces

Heat exchangers can be coated with functional layers to reduce the negative effects of established fouling films. In the process, long-term layer stability is a requirement for the fouling-inhibiting properties of the surface coatings. Various atomic layer deposition (ALD), with layer thicknesses between 10 and 50 nm, and Parylene (polymeric) coatings, with layer thicknesses < 50 µm, are applied to stainless steel (1.4571) and structural steel (1.0038) substrates. The stability against critical thermal process conditions and cleaning media (acids, alkalis, solvents) is examined. The surface free energy of the substrates is determined before and after durability tests using a contact angle measuring device. In this study the targeted water contact angle was between 80° and 110° and the related surface free energy < 45 mN/m. The change in the surface free energy is a measure of the coating durability. The tested Parylene-coated substrates show no significant changes and no layer defects. In the case of the ALD-coated substrates, only the coating with TiO2 deposition using a chlorine-free precursor shows promising results. Non-systematical layer defects and corrosion can sometimes be optically observed on the TiO2 and Al2O3 ALD-coated substrates. A strong increase in the polar part of the surface free energy is observed. This may be due to the physisorption and chemisorption of water with the coating, increasing polar interactions. In further research, fouling experiments must be performed to investigate the influence of the coatings on the induction time.

Surface Modification in CsPb0.5Sn0.5I2Br Inorganic Perovskite Solar Cells: Effects of Bifunctional Dipolar Molecules on Photovoltaic Performance.

Inorganic tin-lead binary perovskites have piqued the interest of researchers as effective absorbers for thermally stable solar cells. However, the nonradiative recombination originating from the surface undercoordinated Sn2+ cations and the energetic offsets between different layers cause an excessive energy loss and deteriorate the perovskite device's performance. In this study, we investigated two thioamide derivatives that differ only in the polar part connected to their common benzene ring, namely, benzenecarbothioamide and 4-fluorophenylcarbothioamide (F-TBA). These two molecules were implemented as modifiers onto the inorganic tin-lead perovskite (CsPb0.5Sn0.5I2Br) surface in the perovskite solar cells. Modifiers that carry C═S and NH2 functional groups, equipped with lone electron pairs, can autonomously associate with surface Sn2+ through coordination and electrostatic attraction mechanisms. This interaction serves effectively to passivate the surface. In addition, due to the permanent dipole moment of the intermediate layer, an interfacial dipole field appears at the PCBM/CsPb0.5Sn0.5I2Br interface, reducing the electron extraction potential barrier. Consequently, the planar solar cell with an ITO/PEDOT:PSS/CsPb0.5Sn0.5I2Br/PCBM/BCP/Ag layered structure featuring an F-TBA surface post-treatment demonstrated a noteworthy power conversion efficiency of 14.01%. Simultaneously, after being stored for 1000 h in an inert atmosphere glovebox, the non-encapsulated CsPb0.5Sn0.5I2Br solar cells managed to preserve 94% of their original efficiency.

Interaction between hydrophobic chitosan derivative and asphaltene in heavy oil to reduce viscosity of heavy oil

The high viscosity of heavy oil made it difficult to exploit and transport heavy oil in pipeline. In this research, N-[(2-hydroxy-3-trimethylammonium) propyl] O-stearoyl chitosan tetraphenylboride (sc-CTS-st) was synthesized from chitosan, 2, 3-epoxy-propyl trimethyl ammonium chloride, sodium tetraphenylboron and stearyl chloride. sc-CTS-st contains long chain saturated aliphatic hydrocarbon, hydroxyl group and benzene ring, which could be dissolved in heavy oil fully and interacted with asphaltene. At 50 °C, the viscosity of heavy oil could be reduced to 13,800 mPa·s at most, with a viscosity reduction rate of 57.54 %. SEM and XRD showed that sc-CTS-st could affect the supramolecular accumulation structure of asphaltenes. Using FT-IR, sc-CTS-st could interact with asphaltene in the form of hydrogen bonds using the polar parts of the molecule, thereby weakening the self-association between asphaltene molecules. Molecular simulation was used to demonstrate the interaction mechanism between chitosan derivatives and asphaltenes. sc-CTS-st interacted with asphaltene through chemical bonding and influenced the self-association of asphaltene molecules. In addition, the non-polar portion of sc-CTS-st molecules could form a coating on the outside of the asphaltenes stacking structure, thus shielding or reducing the polarity of the stacking structure surface.

Foraminifera and Paleogene Stratigraphy of the Submarine Lomonosov Ridge, Arctic Ocean

Materials on the Paleogene biostratigraphy of the Lomonosov Ridge in the Arctic Ocean are presented, including new data on foraminifers from the M0004A borehole section (interval 390–391 m) in its polar part. The studied benthic foraminifers are united into the complex with Reticulophragmium coksuvorovae of the upper Zelandian–the lower Thanetian stages, which includes some characteristic species of the North Atlantic and West Siberian basins. It also contains information about the connection of these Arctic seas in the Paleocene time.

New trends in couple-stress hyperelasticity

This communication reconsiders and reorganises parts of existing knowledge that refers to Cosserat-type hyperelasticity formulations in a manner that respects and pays tribute to the early development pattern of the couple-stress theory and, also, associates with it more recent findings and relevant discoveries related to a certain type of polar hyperelastic behaviour of fibrous composites. It further shows that these different branches of couple-stress theory can both emanate, as special cases, from a common, more general, advanced theoretical hyperelasticity framework. It thus reveals that proper completion of any relevant theoretical formulation requires in advance specification of a pair of kinematic parameters, each of which (1) is related, in a virtual or actual manner, to the observed global, macroscopic elastic deformation of the material, but (2) is principally relevant to the polar part of the observed material response. The first of these parameters represents a pseudovector field whose gradient is energetically reciprocal to the emerging couple-stress field, while the second represents either a vector or a pseudovector field that serves specific constitutional needs characterising the source of the anticipated polar material response. Different versions of couple-stress theory formulations, thus, are obtained by appropriately choosing or suitably tuning that pair of kinematic parameters. It is also seen that, regardless of the employed couple-stress theoretical model, full solution of a relevant well-posed boundary value problem is generally achievable with use of a two-step solution process. The first step includes determination of the deviatoric couple-stress and the actual spin vector of the global material deformation. In the second step, these initial findings enable formation of an additional differential equation whose solution leads to determination of the spherical part of the couple-stress.

Chromophores assisted phytochemicals and pheromones coatings on porous inorganic layers for enhancing anti-corrosion and photocatalytic properties

This work aims to enhance the anti-corrosion and photocatalytic activity of porous inorganic layers through a novel approach involving the exploitation of chromophores derived from phytochemicals and pheromones. Herein, organic acid (carminic acid) and organic salt (indigo carmine) obtained from pheromones and phytochemicals, respectively, are utilized to modulate the porous surface of inorganic layers produced on AZ31 Mg alloy via plasma electrolytic oxidation. Such pheromones and phytochemicals coatings have a double link inside them along with negatively charged functional groups, which enabled the sealing of the sponge-like structure of the inorganic layer through a couple of bonding mechanisms, such as hydrogen bonding, π-π interaction, as well as electrostatic interactions between polar parts of such organic molecules and cationic species generated from the inorganic layer. The phytochemical coating exhibited superior electrochemical stability compared to other samples, as demonstrated by its high polarization resistance (1.27 × 10+8 Ω.cm+2). Additionally, the phytochemical coating demonstrated the ability to photodegrade methylene blue, achieving a photocatalytic efficiency of 99.47 %. The stacked and parallel interactions of the phytochemical and/or phermonic layer on the surface of inorganic layers were explored with the aid of density functional theory.

In vitro nematicidal and acaricidal effect of biosurfactants produced by Bacillus against the root-knot nematode Nacobbus aberrans and the dust mite Tyrophagus putrescentiae.

In the present study, the nematicidal and acaricidal activity of three biosurfactants (BS) produced by strains of the Bacillus genus was evaluated. The BS produced by the Bacillus ROSS2 strain presented a mortality of 39.29% in juveniles (J2) of Nacobbus aberrans at a concentration of 30 mg/mL, this same strain is the one that presented the highest mortality in Tyrophagus putrescentiae, which was 57.97% at a concentration of 39 mg/mL. The BS were qualitatively identified by thin layer chromatography and are lipid in nature based on the retention factor (Rf). While the GC-MS analysis identified two main compounds that are 4,7-Methano-1H-indene-2,6-dicarboxylic acid, 3a,4,7,7a-tetrahydro-1, and Methyl 4-(pyrrol-1-yl)-1,2,5-oxadiazole-3-carboxylate1, which is the polar part indicated by the presence of dicarboxylic acid and carboxylate groups; while the non-polar portion can be interpreted as a hydrocarbon chain of variable length. Based on the present results, BS can be an alternative for the biocontrol of the root-knot nematode N. aberrans and the mite T. putrescentiae.

Nanoscale chemical heterogeneity enables the co-existence of opposing superhydrophobic and hygroscopic properties

Superhydrophobicity and hygroscopicity are two properties that are theoretically exclusive to each other. The fabrication of functional fabrics with these two properties remains very challenging. In this work, it is demonstrated that a non-sticky superhydrophobic and hygroscopic fabric coating can be prepared via the photo polymerization of hexadecyl acrylate and methacrylic acid. On coating surface, the phase-separation-induced chemical heterogeneity has a unique feature of possessing elevated continuous hydrophobic domain and depressed hydrophilic domain, as evidenced by atomic force microscopy measurement. The elevation of hydrophobic domain (i.e., depression of hydrophilic domain) allows the hydrophilic domain to make negligible contribution to the surface wettability to water drop, but can absorb water molecules, thus inducing the unique superhydrophobic but hygroscopic property. The coating has a very low total surface energy of 22.61 mN m−1, with its polar part (0.01 mN m−1) being negligible, thereby showing a high static water contact angle of ~112° on flat glass slide. The coated polyester fabric shows a non-sticky superhydrophobicity with a static water contact angle of ~151° and a water shedding angle of ~10°, as well as good hygroscopic and anti-static properties. We anticipate that this novel coating and the reported strategy of generating the particular chemical heterogeneity may lead to the development of advanced special wettability coatings for various applications.

Using Different Surface Energy Models to Assess the Interactions between Antiviral Coating Films and phi6 Model Virus.

High molecular weight chitosan (HMWCh), quaternised cellulose nanofibrils (qCNF), and their mixture showed antiviral potential in liquid phase, while this effect decreased when applied to facial masks, as studied in our recent work. To gain more insight into material antiviral activity, spin-coated thin films were prepared from each suspension (HMWCh, qCNF) and their mixture with a 1:1 ratio. To understand their mechanism of action, the interactions between these model films with various polar and nonpolar liquids and bacteriophage phi6 (in liquid phase) as a viral surrogate were studied. Surface free energy (SFE) estimates were used as a tool to evaluate the potential adhesion of different polar liquid phases to these films by contact angle measurements (CA) using the sessile drop method. The Fowkes, Owens-Wendt-Rabel-Kealble (OWRK), Wu, and van Oss-Chaudhury-Good (vOGC) mathematical models were used to estimate surface free energy and its polar and dispersive contributions, as well as the Lewis acid and Lewis base contributions. In addition, the surface tension SFT of liquids was also determined. The adhesion and cohesion forces in wetting processes were also observed. The estimated SFE of spin-coated films varied between mathematical models (26-31 mJ/m2) depending on the polarity of the solvents tested, but the correlation between models clearly indicated a significant dominance of the dispersion components that hinder wettability. The poor wettability was also supported by the fact that the cohesive forces in the liquid phase were stronger than the adhesion to the contact surface. In addition, the dispersive (hydrophobic) component dominated in the phi6 dispersion, and since this was also the case in the spin-coated films, it can be assumed that weak physical van der Waals forces (dispersion forces) and hydrophobic interactions occurred between phi6 and the polysaccharide films, resulting in the virus not being in sufficient contact with the tested material during antiviral testing of the material to be inactivated by the active coatings of the polysaccharides used. Regarding the contact killing mechanism, this is a disadvantage that can be overcome by changing the previous material surface (activation). In this way, HMWCh, qCNF, and their mixture can attach to the material surface with better adhesion, thickness, and different shape and orientation, resulting in a more dominant polar fraction of SFE and thus enabling the interactions within the polar part of phi6 dispersion.

Role of the Polar Proportion of Compound Collectors in Low-Rank Coal Flotation Upgrading: Insights from the Molecular Scale

The compound collector, composed of polar and nonpolar parts, is a current research hotspot in low-rank coal (LRC) flotation because of its outstanding flotation efficiency and cost-effectiveness. However, the selection of compound proportions lacks theoretical guidance. In this study, we comprehensively investigate the internal mechanism underlying the influence of the compound proportion (oleic acid (OA):dodecane (DD)) on LRC flotation. The molecular dynamics (MD) simulation between bubble and oil film was simultaneously employed to study the surface interactions between three phases in contact. The compound proportion of OA:DD = 1:3 was found to be the most conductive for Zhuanlongwan coal flotation, which provides a robust collecting capacity while minimizing excessive interaction with water. Thus, the spreading area is the largest and the interaction energy between collectors and LRC is the highest. Additionally, the oil film formed at this ratio has the best hydrophobicity, resulting in the fastest adhesion speed of the bubble and the most stable bubble adhesion. Proportions of OA:DD above 1:3 promote self-aggregation of polar collectors, leading to a worsened spreading of the oil film. Conversely, proportions below 1:3 result in weak interaction with LRC, leading to a smaller spreading area and reduced hydrophobicity. Ultimately, we propose the LRC–compound collector matching principle, which suggests that the best proportion of compound collectors fits well with the oxygen-containing sites on the LRC surface.

Molecular dynamics simulation study on interfacial behaviors of betaines and extended surfactants

The mixed system between different surfactants has characteristic and synergy to reduce the oil/water interfacial tension (IFT). As the reservoir conditions become more and more severe, it is necessary to explore new surfactants suitable for complex geological environments. In this work, we designed the mixed systems between betaine and extended surfactants, and studied the interfacial properties at the decane/water interface by molecular dynamics (MD) simulations and interfacial tension measurements. The effects of betaine structure and oxypropylene (PO) chain length of extended surfactant on the interfacial behaviors were analyzed in detail from the density profile, tilt angle, average rising height of PO unit and radial distribution function. The results showed that the polar part of betaine extended into the water phase and the hydrophobic chain was more upright in the mixed system due to the electrostatic interaction. For the mixed system, the rise height change of the PO unit indicated that the interfacial behavior of short PO chain was controlled by betaine structure, while that of long PO chain was independent of betaine structure because of the poor deformation ability of it. IFT experiments showed that xylyl substituted alkyl sulfobetaine (XSB) mixing with the short PO chain extended surfactant system had a significant synergistic effect to produce ultra-low IFT but had a negative effect with the long PO chain extended surfactant. This work demonstrated that the steric hindrance of betaine and the PO chain length of extended surfactant synergistically affected the interfacial arrangement and IFT of surfactants, which was of significance for improving and designing more effective surfactant flooding systems to enhance oil recovery.

Research on the wound healing effect of Shengji Huayu Formula ethanol extract-derived fractions in streptozotocin-induced diabetic ulcer rats

BackgroundDiabetic ulcer is a common complication of diabetes. It is characterized by a long-term disease course and high recurrence rate. Shengji Huayu Formula (SHF) is an effective formula for treating diabetic ulcers. However, the specific effective parts of SHF remain unclear. Clarifying the active polar site of SHF would be helpful to refine research on the components in SHF that promote wound healing. This research aims to focus on evaluating the activity of polar fractions.MethodsA diabetic rat model was established by intraperitoneally injecting streptozotocin (STZ) and was adopted to confirm the therapeutic effect of SHF. Four different polarity parts were extracted from SHF and prepared into a cream to evaluate the activity. High-performance liquid chromatography (HPLC) was used to detect chemical constituents in chloroform extracts.ResultsIt was discovered that dracorhodin, aloe-emodin, rhein, imperatorin, emodin, isoimperatorin, chrysophanol, physcion, and tanshinone IIA were the main components of the chloroform extract from SHF. The results revealed that chloroform extract could effectively accelerate diabetic wound healing by promoting collagen regeneration and epidermal repair. Chloroform extract of SHF could stimulate the generation of vascular endothelial growth factor (VEGF). The results are also indicated that the effective active fraction was the chloroform part, and the method of detecting the main chemical constituents in the active part was successfully established.ConclusionSHF could improve diabetic ulcers by promoting granulation tissue synthesis. In this study, four polar parts (petroleum ether, chloroform, ethylacetate, n-butanol) were extracted from a 95% ethanol extract. In contrast, chloroform polar parts showed a higher wound closure rate, stimulated more collagen regeneration and promoted more production of vascular endothelial cells. In conclusion, the chloroform extract of SHF was the effective polar part in ameliorating diabetic wound healing.

Defensive Specialized Metabolites from the Latex of Euphorbia jolkinii.

Plant latex is sequestered in laticiferous structures and exuded immediately from damaged plant tissues. The primary function of plant latex is related to defense responses to their natural enemies. Euphorbia jolkinii Boiss. is a perennial herbaceous plant that greatly threaten the biodiversity and ecological integrity of northwest Yunnan, China. Nine triterpenes (1-9), four non-protein amino acids (10-13) and three glycosides (14-16) including a new isopentenyl disaccharide (14), were isolated and identified from the latex of E. jolkinii. Their structures were established on the basis of comprehensive spectroscopic data analyses. Bioassay revealed that meta-tyrosine (10) showed significant phytotoxic activity, inhibiting root and shoot growth of Zea mays, Medicago sativa, Brassica campestris, and Arabidopsis thaliana, with EC50 values ranging from 4.41 ± 1.08 to 37.60 ± 3.59µg/mL. Interestingly, meta-tyrosine inhibited the root growth of Oryza sativa, but promoted their shoot growth at the concentrations below 20µg/mL. meta-Tyrosine was found to be the predominant constituent in polar part of the latex extract from both stems and roots of E. jolkinii, but undetectable in the rhizosphere soil. In addition, some triterpenes showed antibacterial and nematicidal effects. The results suggested that meta-tyrosine and triterpenes in the latex might function as defensive substances for E. jolkinii against other organisms.

Multiscale Modeling Unravels the Influence of Biomembranes on the Photochemical Properties of Embedded Anti-Oxidative Polyphenolic and Phenanthroline Chelating Dyes.

The embedding of caffeate methyl ester, the flavonoids luteolin and quercetin, and the o-phenanthroline and neocuproine in a liquid disordered lipid bilayer has been studied through extensive atomistic calculations. The location and the orientation of these bio-active antioxidants are explained and analyzed. While the two phenanthrolines strongly associate with the lipid tail region, the other three compounds are rather found among the head groups. The simulations showcase conformational changes of the flavonoids. Through the use of a hybrid quantum mechanics-molecular mechanics scheme and supported by a profound benchmarking of the electronic excited-state method for these compounds, the influence of the anisotropic environment on the compounds' optical properties is analyzed. Influences of surrounding water molecules and of the polar parts of the lipids on the transition dipole moments and excited-state dipole moments are weighted with respect to a change in conformation. The current study highlights the importance of the mapping of molecular interactions in model membranes and pinpoints properties, which can be biomedically used to discriminate and detect different lipid environments.

Progress and challenges of Microwave-assisted pretreatment of lignocellulosic biomass from circular bioeconomy perspectives

The recent scenario has witnessed the augmenting demand for energy precursors primarily from renewable ways in respect of the natural environment. The high energy along with the cost-intensive nature of the conventional approaches directed the researchers to find out an effective and promising method that principally uses the microwave for the pretreatment. The formation of heat energy from electromagnetic energy through polar particle rotation would be noted to be the core principle of the aforesaid effective approach. The microwave treatments speed up the destruction of complex structure of the biomass by applying a specific range of heat over the polar parts in a selective manner in the aqueous medium. In this review, the implementation of microwave-assisted green approaches for modeling an integrated circular bioeconomic strategy to potentially use lignocellulosic biomass for bioproducts is discussed.