Genomes carry the genetic blueprint of all living organisms. Their organization requires strong condensation as well as carefully regulated accessibility to specific genes for proper functioning of ...their hosts. The study of the structure and dynamics of the proteins that organize the genome has benefited tremendously from the development of single-molecule force spectroscopy techniques that allow for real-time, nanometer accuracy measurements of the compaction of DNA and manipulation with pico-Newton scale forces. Magnetic tweezers in particular have the unique ability to complement such force spectroscopy with the control over the linking number of the DNA molecule, which plays an important role when DNA organizing proteins form or release wraps, loops, and bends in DNA. Here, we describe all the necessary steps to prepare DNA substrates for magnetic tweezers experiments, assemble flow cells, tether DNA to magnetics bead inside flow cell, and manipulate and record the extension of such DNA tethers. Furthermore, we explain how mechanical parameters of nucleo-protein filaments can be extracted from the data.
Two-dimensional transition metal dichalcogenide semiconductors are intriguing hosts for quantum light sources due to their unique opto-electronic properties. Here we report that strain gradients ...induced by substrate patterning result in spatially and spectrally isolated quantum emitters in mono- and bi-layer WSe2. By correlating localized excitons with localized strain-variations, we show that the quantum emitter emission energy can be red-tuned up to a remarkable ~170 meV. We probe the fine-structure, magneto-optics, and second order coherence of a strained emitter. These results raise the prospect to strain-engineer quantum emitter properties and deterministically create arrays of quantum emitters in two-dimensional semiconductors.
Purpose
The blood-brain barrier limits the application of idarubicin in the therapy of glioblastoma multiforme. Biodegradable, intracranial wafers with prolonged release may increase therapy ...efficiency.
Methods
Blank wafers, wafers containing 5%
w
/w and 10% w/w of idarubicin were formulated by solution casting from poly(L-lactide-co-glycolide) and poly(glycolide-co-ε-caprolactone). The following methods were used: NMR, GPC, DSC, FTIR, AFM, UV-VIS, and a viability and proliferation assay for idarubicin action (U87MG cell line).
Results
Wafers showed a surface with numerous immersions and hills. A lack of interactions between idarubicin and the copolymers was observed. The substance was entrapped in the matrix and released in two phases for all wafers with the appropriate bolus and maintenance dose. The burst effect was observed for all wafers, however, the biggest bolus for poly(L-lactide-co-glycolide) wafers containing 5% w/w of idarubicin was noted. The stable and steady degradation of poly(glycolide-co-ε-caprolactone) wafers containing 5% w/w of idarubicin ensures the most optimal release profile and high inhibition of proliferation.
Conclusions
Copolymer wafers with idarubicin are an interesting proposition with great potential for the local treatment of glioblastoma multiforme. The release rate and dose may be regulated by the amount and kind of wafers for various effects.
The interest in combining chemosensitizers with cytostatics in cancer therapy is growing, which causes also a need to develop their delivery systems. Example of the combination with beneficial ...therapeutic effects is docetaxel (Dtx) and resveratrol (Res). Although poly(lactide)‐co‐poly(ethylene glycol) (PLA–PEG) micelles have been considered as one of the most promising platforms for drug delivery, their properties may depend on the stereoisomeric form of hydrophobic block. Therefore, the aim of this study was evaluation of the effect of PLA block on co‐encapsulation and release rate of Dtx and Res, which has not been studied so far. This article presents a comparison of single‐ (Dtx or Res) and dual‐drug (Dtx and Res) loaded micelles obtained from poly(l,l‐lactide)‐co‐poly(ethylene glycol) (PLLA‐PEG) and poly(d,l‐lactide)‐co‐poly(ethylene glycol) (PDLLA‐PEG). The analyzes of the micelles have been conducted including morphology, drug(s) encapsulation efficiency, intermolecular interactions, in vitro drug release, and cytotoxicity. Differences in drug loading ability and release profile have been observed between Res and Dtx but also depending on the polymer and number of drugs in micelles (single vs. dual loaded). The PLLA‐PEG micelles have a significantly higher Dtx encapsulation capacity than PDLLA‐PEG micelles. The highest cytotoxicity was shown for Dtx and Res dual‐loaded micelles, regardless of the polymer. The findings may be used for selection of PLA‐based drug delivery systems containing Dtx and Res.
The aim of this study was to confirm that vitamin D supplementation of young soccer players during eight-week high-intensity training would have a significant effect on their motion activity. The ...subjects were divided into two groups: the experimental one, which was supplemented with vitamin D (SG,
= 20), and the placebo group (PG,
= 16), which was not supplemented with vitamin D. All the players were subjected to the same soccer training, described as High-Intensity Interval Training (HIIT). The data of the vitamin D status, time motion parameters and heart rate were collected just before and after the intervention. A significant increase in 25(OH)D concentration (119%) was observed in the supplemented group, while the non-supplemented group showed a decrease of 8.4%. Based on the obtained results, it was found that physical activity indicators in the players were significantly improved during small-sided games at the last stage of the experiment. However, taking into account the effect of supplementation with vitamin D, there were no statistically significant differences between the placebo and the supplemented groups; thus, the effect size of the conducted experiment was trivial.
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