A series of aryl-substituted β-diketonate adducts with 5,5′-di(heptadecyl)-2,2′-bipyridine has been synthesised. All the compounds exhibit a mesomorphic (smectic) behaviour. It has been shown that ...the metal ion does not drastically influence the mesophase type and the transition temperatures. A thin film of Eu(III) complex shows more effective luminescence in the aligned state.
Plant protoplasts are widely used for genetic manipulation and functional studies in transient expression systems. However, little is known about the molecular pathways involved in a cell response to ...the combined stress factors resulted from protoplast generation. Plants often face more than one type of stress at a time, and how plants respond to combined stress factors is therefore of great interest. Here, we used protoplasts of the moss
as a model to study the effects of short-term stress on the chloroplast proteome. Using label-free comparative quantitative proteomic analysis (SWATH-MS), we quantified 479 chloroplast proteins, 219 of which showed a more than 1.4-fold change in abundance in protoplasts. We additionally quantified 1451 chloroplast proteins using emPAI. We observed degradation of a significant portion of the chloroplast proteome following the first hour of stress imposed by the protoplast isolation process. Electron-transport chain (ETC) components underwent the heaviest degradation, resulting in the decline of photosynthetic activity. We also compared the proteome changes to those in the transcriptional level of nuclear-encoded chloroplast genes. Globally, the levels of the quantified proteins and their corresponding mRNAs showed limited correlation. Genes involved in the biosynthesis of chlorophyll and components of the outer chloroplast membrane showed decreases in both transcript and protein abundance. However, proteins like dehydroascorbate reductase 1 and 2-cys peroxiredoxin B responsible for ROS detoxification increased in abundance. Further, genes such as thylakoid ascorbate peroxidase were induced at the transcriptional level but down-regulated at the proteomic level. Together, our results demonstrate that the initial chloroplast reaction to stress is due changes at the proteomic level.
Background. The observed sharp increase in patients with avascular necrosis of the femoral head (ANFH) associated with a new COVID-19 infection determines the need to find some new effective ...strategies for surgical treatment to achieve long-term positive results. Aim of the study is to make a comparative assessment of surgical treatment results of patients with early-stage avascular necrosis of the femoral head using different techniques of core decompression and autogenous bone grafting of the femoral head. Methods. We performed a comparative analysis of the treatment results of patients with early stages of ANFH. The patients were divided by the treatment method into two groups: control and main. Surgical treatment in the control group (n = 19) consisted of an open decompression and autogenous bone grafting of the femoral head using the Rosenwasser’s “light bulb” technique. The main group (n = 17) included the patients who had undergone the developed combined impaction autografting of the femoral head. Clinical and functional assessment of the treatment results was performed using the Harris Hip Score (HHS) questionnaire and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score. Assessment was performed preoperatively and at 3, 6, and 12 months postoperatively. Results. The performed comparative analysis showed statistically significant difference in clinical and functional results after operative treatment in patients of the control and the main groups at all follow-ups. Change of the HHS values presented as Me (Q1;Q3) in patients of both groups at 3, 6 and 12 months was 77.0 (68.0;84.0) and 82.0 (75.0;91.0), p = 0.001; 79.0 (69.0;85.0) and 88.0 (79.0;95.0), p0.001; 81.0 (71.0;86.0) and 90.0 (85.0;92.0), p0.001, respectively. According to the WOMAC, the following dynamics was revealed for the same values: 30.0 (25.0;35.0) and 25.0 (21.0;32.0), p = 0.002; 27.0 (22.0;33.0) and 20.0 (17.0;27.0), p0.001; 24.0 (17.0;30.0) and 15.0 (13.0;24.0), p0.001. Conclusion. Comparative assessment of efficacy of the open core decompression with autogenous bone grafting of the femoral head defect using the light bulb technique and closed intralesional resection of necrosis focus with combined impaction grafting of the femoral head showed that the minimal damage to para- and intraarticular tissues when performing the approach to the area of the pathological focus and the main stages of the operation allows to achieve the best clinical and functional results and create optimal conditions for bone remodeling in the grafting area.
Novel hybrid systems based on the poly(methyl methacrylate) (PMMA) matrix and Eu(III) and Tb(III) tris(β-diketonates) complexes with 1,10-phenanthroline were synthesized and analyzed as ...light-conversion materials. Solutions of the Tb(III) and Eu(III) complexes doped into PMMA were spin-coated to fabricate films with various concentrations of luminophores. Long hydrocarbon substituents in the structure of complexes inhibit their crystallization. In turn, it allows to vary the luminophore content in a polymer matrix in a broader range and achieve the maximum of emission with higher concentrations of dopants. The addition of the Tb(III) complex to the system results in a 26% increase in the relative luminescence quantum yield of the Eu(III) ions due to an additional energy transfer from the Tb(III) compound. The results of this work illustrate that although the Eu(III) and Tb(III) complexes exhibit lower rate and efficiency of energy transfer than their well-known Tb(acac)3 and Eu(tta)3 analogues, the structural features of lanthanide complexes allow to efficiently dope a PMMA matrix with considerably larger amounts of luminophores. It offers broader application opportunities for the coordination Ln(III) compounds as polyfunctional materials for optics and optoelectronics.
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•Novel hybrid luminescence systems based on the PMMA and Eu(III) and Tb(III) complexes were presented.•Luminescence composites with efficient energy transfer from the Tb(III) complex to Eu(III) complex were obtained.•Light-converters with the ability in a wide range to vary the content of luminophore were created.
A series of new liquid-crystalline adducts of lanthanum tris(β-diketonates) displaying nematic and smectic mesomorphism was synthesised and investigated. The temperatures and thermodynamic parameters ...of the phase transitions were determined. Even-odd alternation of the nematic-isotropic transition was observed in the series of synthesised complexes. It was found that films of the obtained liquid-crystal complexes are vitrified when cooling, and packings of molecules, formed in the mesophase, are retained. Interlayer distances were determined and a model of packing of molecules in the mesophase was suggested based on data obtained by a small-angle X-ray scattering method.
A polystyrene polymer and an Eu(III) anisometric complex were used to produce films with various luminophore contents. Due to its structural features (anisotropic form and long hydrocarbon ...substituents at molecular ends), the luminophore used in this research is an amorphous powder that is highly soluble in organic polar and nonpolar solvents as well as miscible with polymers. These features allow this luminophore to be incorporated into polymer networks without losing its luminescence efficiency due to self-quenching. The effect of temperature on the lifetime and luminescence intensity of the Eu(III) films was studied. It was found that their maximum luminescence intensity and lifetime are 2 times higher than those of other lanthanide-containing β-diketonate thermosensors. The photostability of the films was studied. It was demonstrated that the films can be used as materials for fluorescent thermometers that operate in the temperature range of 303–363 K.
•Novel luminescence materials based on the PS doped with the anisometric Eu(III) complex were presented.•An increase in luminophore content in the PS matrix is found to significantly improve the photostability of the composites.•Thermosensitive materials to measure temperatures in the range of 303–363 K were created.
•Nematic liquid crystal mixtures were doped with luminescent europium complex.•Electrohydrodynamic instability leads to the switching of luminescence intensity.•Photopatterning of the luminescence ...was achieved by photopolymerization.
Stimuli-responsive self-organized soft matter such as liquid crystals, polymers, gels attracts great attention due to a variety of possible applications in modern technologies. Electroinduced hydrodynamic (EHD) instability in liquid crystals is one of long-discovered effects that shows a great potential for future applications. However, this effect is insufficiently studied and its practical implementation has yet to be found. In the present paper, we applied an EHD instability to tuning luminescent properties of nematic mixtures doped with a highly emissive europium complex, which has good solubility in a liquid crystalline (LC) matrix and high quantum yield of luminescence. Nematic mixtures studied in this work possess negative anisotropy of dielectric constant and positive anisotropy of conductivity that allow for observing convective EHD patterns induced by ionic conductivity. The influence of field frequency on the threshold voltage was studied and optimal conditions for induction of EHD patterns were determined. The luminescence intensity was found to substantially decrease or increase under an applied electric field depending on the alignment behavior of LC molecules inside the cells and the angle of observation. In a tilted cell (60°), the emission intensity gradually increases under applied electric field and reaches values ca. 2.5 times higher than in zero field conditions. This phenomenon is associated with alignment of the europium complex molecules along electric field direction (cooperatively with LC molecules) and EHD-induced light scattering. Kinetics of electrooptic switching was studied and different approaches to luminescence photopatterning of the studied nematic mixture with polymerizable monoacrylate and diacrylate were demonstrated.
New complexes of Eu(III) and Tb(III) tris(β-diketonates) with Lewis bases were synthesized. The spin-coating technique was used to produce composite films consisting of polystyrene (PS) polymer doped ...with mixtures of Eu(III) and Tb(III) complexes with different ratio of luminophores. An increase in the content of the Tb(III) complexes in the 5 %Eu x%Tb films intensifies emission of both the Tb3+ and Eu3+ ions due to occurring intermolecular energy transfer and leads to a significant increase in photostability of the material (the loss of luminescence intensity ratio did not exceed 0.5 %/hour). These photostable films were characterized as potential luminescent temperature sensors. The temperature sensitivity of their luminescence intensity and lifetime was investigated in the range of 298–383 K. The maximum absolute sensitivity of the films reaches 6.00 µs/K and exceeds that of all known lanthanide-containing thermal sensors designed for measuring physiological temperatures. In combination with changeable luminescence colors of the films, such a sensitivity makes these materials promising colorimetric thermal sensors for in situ temperature measurements.
•Synthesis of novel Eu(III) and Tb(III) β-diketonate complexes.•Photostable composite polystyrene films with different ratio of luminophores were prepared.•Obtained composite films were characterized as promising luminescent sensors of temperature.
Luminescent adducts of Eu(III) tris(β-diketonate) with 1,10-phenanthroline were synthesized. The effect of the β-diketone structure on thermodynamic and photophysical properties of Eu(III) complexes ...was characterized. Sensitization of Eu(III) ion by various β-diketones was evaluated. The synthesized compounds are shown to form isotropic vitrified structures at room temperature allowing to produce optically isotropic vitrified films with light transmittance of over 90% and efficient luminescence. These photostable films were characterized as potential luminescent temperature sensors.
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•Synthesis of mesogenic europium(III) β-diketonate complexes.•Optically isotropic microscale vitrified films of europium(III) complexes.•Mesogenic europium(III) β-diketonate complexes are promising materials for luminescent temperature sensors.
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