Singular limits solution for two-dimensional elliptic problems involving exponential nonlinearities with nonlinear gradient terms and singular weights

Given Ω bounded open regular set of ${\mathbb{R}^2}$ , ${q_1,\ldots, q_K \in \Omega}$ , ${\varrho : \Omega \longrightarrow [0,+\infty)}$ a regular bounded function and ${V: \Omega \longrightarrow [0,+\infty)}$ a bounded fuction. We give a sufficient condition for the model problem $$(P):\qquad-{\Delta}u -{\lambda}\varrho(x)|{\nabla}u|^2 = \varepsilon^{2}V(x)e^u$$ to have a positive weak solution in Ω with u = 0 on ?Ω, which is singular at each q _i as the parameters ${\varepsilon}$ and λ tend to 0, essentially when the set of concentration points q _i and the set of zeros of V are not necessarily disjoint.     

Structural,electronic and optical properties of fluorite-type compounds

An oscillator chain with dynamical traps and additive white noise is considered. Its dynamics are studied numerically. New type nonequilibrium phase transitions are shown to arise in the case when the trap effect is pronounced. Locally they manifest themselves in distortion of the symmetry of particle arrangement. Depending on the system parameters, the particle arrangement is characterized by the corresponding distributions taking either a bimodal form, or a twoscale one, or a unimodal onescale form that, however, deviates substantially from the Gaussian distribution. The particle velocities also exhibit a number of anomalies, in particular, their distribution can be extremely wide or take a quasi-cusp form. A large number of various cooperative structures and superstructures are found in the visualized time patterns. In a certain sense their evolution is independent of the individual particle dynamics, enabling us to regard them as dynamical phases.     

Gallic Acid-Loaded Sodium Alginate-Based (Polyvinyl Alcohol-Co-Acrylic Acid) Hydrogel Membranes for Cutaneous Wound Healing: Synthesis and Characterization

Traditional wound dressings often cannot treat wounds caused by bacterial infections or other wound types that are insensitive to these wound treatments. Therefore, a biodegradable, bioactive hydrogel wound dressing could be an effective alternative option. The purpose of this study was to develop a hydrogel membrane comprised of sodium alginate, polyvinyl alcohol, acrylic acid, and gallic acid for treating skin wounds. The newly developed membranes were analyzed using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), sol-gel fraction, porosity, mechanical strength, swelling, drug release and data modelling, polymeric network parameters, biodegradation, and antioxidation (DPPH and ABTS) and antimicrobial activity against Gram-positive and negative bacteria. The results revealed that hydrogel membranes were crosslinked successfully and had excellent thermal stability, high drug loading, greater mechanical strength, and exhibited excellent biodegradation. Additionally, the swelling ability and the porosity of the surface facilitated a controlled release of the encapsulated drug (gallic acid), with 70.34% release observed at pH 1.2, 70.10% at pH 5.5 (normal skin pH), and 86.24% at pH 7.4 (wounds pH) in 48 h. The gallic acid-loaded hydrogel membranes showed a greater area of inhibition against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli bacteria as well as demonstrated excellent antioxidant properties. Based on Franz cell analyses, the permeation flux of the drug from optimized formulations through mice skin was 92 (pH 5.5) and 110 (pH 7.4) μg/cm²·h⁻¹. Moreover, hydrogel membranes retained significant amounts of drug in the skin for 24 h, such as 2371 (pH 5.5) and 3300 µg/cm² (pH 7.4). Acute dermal irritation tests in rats showed that hydrogel membranes were nonirritating. Hydrogel membranes containing gallic acid could be an effective option for improving wound healing and could result in faster wound healing.     

Light-driven directed motion of azobenzene-coated polymer nanoparticles in an aqueous medium

Azobenzene-coated polymer nanoparticles in the 16-nm-diameter range act as phototriggered nanomotors combining photo to kinetic energy conversion with optical control through light intensity gradients. The grafted dyes act as molecular propellers: their photoisomerization supplies sufficient mechanical work to propel the particles in an aqueous medium toward the intensity minima with velocities of up to 15 μm/s. It is shown that nanoparticles can be driven over tens of micrometers by translating the intensity gradients in the plane. The analysis of the particles motion demonstrates the decisive role of photoisomerization in the transport with a measured driving force that is 3 to 4 orders of magnitude higher than optical forces.     

Synthesis,characterisation and liquid crystalline behaviour of some lanthanides complexes containing two azobenzene Schiff base

Schiff base ligand N,N′-di-(4-butylsalicylidene)-1′,3′-diaminopropane [H₂L] was synthesised by the reaction of substituted azobenzene and 1,3-diaminopropane in 2:1 molar ratio. Four mononuclear lanthanide complexes of the type [Ln(H₂L)LCl] (Ln = LaIII, CeIII, SmIII and GdIII) were synthesised and characterised by ¹H,¹³C NMR, fourier transform infrared (FT-IR) spectroscopy, elemental analysis (CHNO), gas chromotography-mass, magnetic susceptibility and molar conductivity. Thermal properties of the title compounds were studied using the thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) and optical polarising microscopy (OPM). The ligand and coordination compounds exhibit liquid-crystalline properties (smectic A).     

Chemical composition,antioxidant and antimicrobial potential of essential oils from different parts of <Emphasis Type="Italic">Daphne mucronata</Emphasis> Royle

This research work was executed to determine chemical composition, anti-oxidant and anti-microbial potential of the essential oils extracted from the leaves and stem of Daphne mucronata Royle. From leaves and stem oils fifty-one different constituents were identified through GC/MS examination. The antioxidant potential evaluated through DPPH free radical scavenging activity and %-inhibition of peroxidation in linoleic acid system. The stem’s essential oil showed the good antioxidant activity as compared to leaves essential oil. Results of Antimicrobial activity revealed that both stem and leaves oils showed strong activity against Candida albicans with large inhibition zone (22.2?±?0.01, 18.9?±?0.20 mm) and lowest MIC values (0.98?±?0.005, 2.44?±?0.002 mg/mL) respectively. Leaves essential was also active against Escherichia coli with inhibition zone of 8.88?±?0.01 mm and MIC values of 11.2?±?0.40 mg/mL. These results suggested that the plant’s essential oils would be a potential cradle for the natural product based antimicrobial as well as antioxidant agents.

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Simple charge transfer complexes of some new and of some known heterocyclic compounds of selenium and tellurium

Charge transfer (CT) complexes (1:1) of 2,5-dihydrotellurophene and the 3-methyl and 3,4-dimethyl compounds with TCNQ and tetrachlorobenzoquinone (TCB) are reported. The organotellurium compounds failed to give complexes with p-dinitrobenzene (DNB). The variation of solid state (disc) conductivity with temperature and as a function of methyl substituents is considered. The complexes show semi-conducting behaviour and a consideration of these data, together with IR and UV spectroscopic data, in comparison with those for 1,3-dihydro-2-telluraindene given the following order of donor power with respect to TCNQ:

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With respect to a given donor, the order to acceptor power is TCNQ> TCB> DNB.

1,3-Dihydro-2-selanaindene forms a complex with TCNQ. The molecular ionisation potential of the selanaindene is 7.4 eV (by mass spectroscopy) and it has been shown that the compound may be electrochemically oxidized to materials such as C₈H₈SePF₆.

New quinoxalino-1-chalcogenacyclopentanes are reported; namely those derived from selenium, and for the 7,8-dimethyl series, those based on both selenium and tellurium. Their preparation and characterisation are described, and their chemistry shown to be strongly analogous to that of quinoxalino-1-telluracyclopentane. CT complexes of the new Se^II and Te^II compounds (1:1) are prepared with TCNQ which are believed to be strongly ionic.     

Facile synthesis of scheelite-type NdOsO4 directly grown on carbon cloth for oxygen evolution reaction

Journal of Solid State Electrochemistry - In the recent work, the scheelite-type ABO4&nbsp;compound (A = Nd and B = Os) is synthesized via a hydrothermal route directly...     

Novel lanthanum sulfide–decorated zirconia nanohybrid for enhanced electrochemical oxygen evolution reaction

Journal of Solid State Electrochemistry - Metal sulfide and oxides have drawn interest as economical substitutes to noble metal catalysts due to their ability for oxygen evolution reaction (OER)...