Cell behaviors within a confined adhesive area fabricated using novel micropatterning methods

In the field of cell and tissue engineering, there is an increasing demand for techniques to spatially control the adhesion of cells to substrates of desired sizes and shapes. Here, we describe two novel methods for fabricating a substrate for adhesion of cells to a defined area. In the first method, the surface of the coverslip or plastic dish was coated with Lipidure, a non-adhesive coating material, and air plasma was applied through a mask with holes, to confer adhesiveness to the surface. In the second method, after the surface of the coverslip was coated with gold by sputtering and then with Lipidure; the Lipidure coat was locally removed using a novel scanning laser ablation method. These methods efficiently confined cells within the adhesive area and enabled us to follow individual cells for a longer duration, compared to the currently available commercial substrates. By following single cells within the confined area, we were able to observe several new aspects of cell behavior in terms of cell division, cell–cell collisions, and cell collision with the boundary between adhesive and non-adhesive areas.

⁴⁰Ar/³⁹Ar dating of a hydrothermal pegmatitic buddingtonite–muscovite assemblage from Volyn, Ukraine

We determined 40Ar/39Ar ages of buddingtonite, occurring together with muscovite, with the laser-ablation method. This is the first attempt to date the NH4-feldspar buddingtonite, which is typical for sedimentary–diagenetic environments of sediments, rich in organic matter, or in hydrothermal environments, associated with volcanic geyser systems. The sample is a hydrothermal breccia, coming from the Paleoproterozoic pegmatite field of the Korosten Plutonic Complex, Volyn, Ukraine. A detailed characterization by optical methods, electron microprobe analyses, backscattered electron imaging, and IR analyses showed that the buddingtonite consists of euhedral-appearing platy crystals of tens of micrometers wide, 100 or more micrometers in length, which consist of fine-grained fibers of ≤ 1 µm thickness. The crystals are sector and growth zoned in terms of K–NH4–H3O content. The content of K allows for an age determination with the 40Ar/39Ar method, as well as in the accompanying muscovite, intimately intergrown with the buddingtonite. The determinations on muscovite yielded an age of 1491 ± 9 Ma, interpreted as the hydrothermal event forming the breccia. However, buddingtonite apparent ages yielded a range of 563 ± 14 Ma down to 383 ± 12 Ma, which are interpreted as reset ages due to Ar loss of the fibrous buddingtonite crystals during later heating. We conclude that buddingtonite is suited for 40Ar/39Ar age determinations as a supplementary method, together with other methods and minerals; however, it requires a detailed mineralogical characterization, and the ages will likely represent minimum ages.

Study of the effectiveness of fractional laser ablation in patients with atrophic postacne scars using the quantitative scar index

Introduction. Atrophic scars are common in acne patients. Regardless of their number and size, they are persistent defects and reduce patients' quality of life. With a variety of treatment options, effective scar correction remains a challenge. Laser technology continues to evolve and is considered promising for the treatment of scars.The aim of the study was to investigate the effectiveness of the fractional laser ablation method in patients with atrophic postacne scars using the quantitative postacne scar index.Materials and methods. The study involved 60 patients with ARP of II-IV severity, 35 women and 25 men. The patients underwent fractional ablation of scars with an Erbium laser (2940 nm). To assess the scars before and after treatment, we used the post-acne scar severity index according to the quantitative assessment scale according to G.J. Goodman et al. Goodman et al. (2006). The international scales Patient's Satisfaction Score, Physician's Satisfaction Score, and Definitive Graduated Score were used to assess physician and patient satisfaction with the results of the procedures.Results. The quantitative index of postacne scars before treatment ranged from 4.0 to 16.0 points and averaged 10.9±3.56 points; median was 12.0 points (8.0±13.0 points). After fractional laser ablation procedures, improvement of quantitative indexes scores (p<0.05), positive dynamics of the doctor's and patients' evaluation of procedure results were noted; no gender differences were noted.Discussion. Quantitative indices of scar expression reflect the severity of the affected skin areas in patients with postacne. This study confirms the effectiveness of fractional ablation with the Erbium laser in patients with ARP, which is confirmed by a decrease in quantitative scar severity indices. Dynamic growth of PSS, PhSS, DGS indices testifies to high satisfaction of the physician and the patient with the results of treatment and correlates with regression of clinical manifestations in these patients.Conclusion. Despite the limitations and laboriousness of counting quantitative indices of postacne scars, this approach allowed to establish and objectify the clinical efficacy of treatment of patients with ARP by fractionated ablation.

SYNTHESIS OF CARBON DOTS (CDS) AND DETERMINATION OF OPTICAL GAP ENERGY WITH TAUC PLOT METHOD

Carbon Dots (CDs) which have been synthesized using the laser ablation method show the presence of UV-Vis absorption in the wavelength range of 303 nm to 333 nm for absorbance and 495 nm to 503 nm for fluorescence. Changes in the time duration 1, 2, 3 hours of CDs resulted in changes in the optical energy gap. The optical energy gap valuesare distinguished by the type of indirect transition (n=2) is 3.40 eV (1 hour), 3.15 eV (2 hour), 2.85 eV (3 hour) and direct transition (n=1/2) is 2.58 eV (1 hour), 2.31 eV (2 hour), 1.70 eV (1 hour).