The use of ultrasound biomicroscopy in the different stages of retinopathy of prematurity

Purpose. To study anatomical-topographical features of the anterior segment of the eye at different stages of retinopathy of prematurity (ROP) based on the ultrasound biomicroscopy, to determine criteria of disease progression and to assess the possibilities to use the obtained data for an optimization of the laser and surgical treatment.Material and methods. Ultrasound biomicroscopy (UBM) was performed in 217 eyes of 123 premature babies in the gestation terms of 26-34 weeks, of them: at the ROP stage I – 44 eyes (20%) 25 newborn children, at the stage II – 35 eyes (16%) 21 newborn babies, at the stage III – 42 eyes (19%) 24 newborns, at the stage IV – 49 eyes (22.5%) 28 newborns, at the stage V – 47 eyes (21.7%) 25 newborns. the control group consisted of 20 premature babies (40 eyes) without ROP signs and other eye diseases aged from 1 to 4 months.Results. The conducted research allowed to calculate angular and linear parameters for premature babies with no ROP signs, and also for babies of the ac tive ROP stages III, IV and V. Specificity of spatial correlations in structures of the anterior segment of the eye was defined for children with different ROP stages.Сonclusion. Specific structural violations were revealed by the UBM method in the area of the far retinal periphery, as well as in the postzonular and retrolental spaces in case of the ROP stages IV and V. The use of ultrasound biomicroscopy data in the ROP case allows to optimize the parameters of laser irradiation in the ROP stages III and II with adverse types of ROP course, to clarify the volume of surgical intervention at ROP stage IV, identify the optimum area of an operational access at ROP stage V

Improvement of physical and chemical properties of steel implanted with Cr+, Ti+, Si+ ions

Low carbon steels (St3, St45) and a chromium doped steel (St40Cr) were implanted with 15-20 keV T i+, Cr+ or co-implanted with (Ti + Si)+, (Cr + Si)+ ions to a dose of 8 X 1016 ions cm-2 . The composition of the surface region was examined by RBS and nuclear resonance scattering techniques. These analyses showed a relationship between the implanted ion doses and the oxygen concentration in the layer. The hardness of the implanted surface grew with increasing ion dose. This effect is associated with radiation damage and chemical compounds created in the surface regions of the ion-implanted steels. The corrosion properties of the steels were studied and the first results from electrochemical analysis of corrosion behaviour of samples in de-aerated borate buffer solution (pH = 6.5) are discussed

Isobornyl and Isocamphyl Photostabilizers in Poly(lactic acid)-Based Electrospun Fibers

In this work, electrospun polylactide fibers with new photostabilizing additives, 4-methyl-2,6-diisobornylphenol (DIBP) and N-isocamphylaniline (NICA), have been tested under the influence of UV-C radiation (254 nm). The changes in the polymers’ chemical structure under UV-C radiation were revealed through the increase in absorption in the 3600–3100 cm−1 region in regard to the FTIR spectra. In the samples that were irradiated for 1 h, the stabilizing effect of the photoprotectors became most noticeable as the difference in the content of the hydroxyl groups in stabilized and the pure PLA reached a maximum. The TG–DSC method revealed that the most sensitive indicator of the irradiation effect was the glass transition temperature (Tg), which persisted after 2 h of irradiation when using photostabilizers and their combinations. The PLA/DIBP(1) and PLA/NICA(1) samples showed the best results in protecting PLA from UV-C radiation based on the Tg values; although, the mixture of DIBP and NICA was not as effective. The chemical structure of the photostabilized PLA samples was studied using NMR, GPC, and Py–GC/MS analysis. The electrospun polylactide fibers were mechanically tested and the effects of the electrospun samples on cell viability were studied

Tailoring Photoprotection of Polylactide with New Isobornyl Derivatives of Phenol and Aniline

This article is devoted to the development of new photostabilizers for polylactide (PLA), a polymer that is an environmentally friendly alternative to polymers and is based on fossil raw materials. We have elucidated the role of the reaction center of two potential PLA photoprotectors: N-isobornylaniline and 2-isobornylphenol, in reactions occurring in a polymer matrix under the action of UV-C radiation. PLA samples with the photostabilizers were irradiated under a wavelength of 253.7 nm for 4, 8 and 12 h. The effectiveness of the photostabilizers was evaluated based on FTIR spectrometric data, 1H and 13C NMR, scanning electron microscopy and simultaneous thermal analysis (TG-DSC). Both stabilizers led to the protection of ester bonds between monomer units of PLA. However, 2-isobornylphenol proved to be more effective at a concentration of 0.05 wt.%, while the optimal concentration of N-isobornylaniline was 0.5 wt.% by weight. TG-DSC showed that the addition of N-isobornylaniline led to an increase in PLA resistance to thermal decomposition; the temperature of the onset of weight loss increased by 2.8 °C at 0.05 wt.% and by 8.1 °C at 0.5 wt.% of N-isobornylaniline. The photoprotector 2-isobornylphenol, on the contrary, reduced the thermal stability of PLA