Editorial

Abstract It is thought that cells surviving ionizing radiation exposure repair DNA double-strand breaks (DSBs) and restore their genomes. However, the recent biochemical and genetic characterization of DSB repair pathways reveals that only homologous recombination (HR) can function in an error-free manner and that the non-homologous end joining (NHEJ) pathways canonical NHEJ (c-NHEJ), alternative end joining (alt-EJ), and single-strand annealing (SSA) are error-prone, and potentially leave behind genomic scars and altered genomes. The strong cell cycle restriction of HR to S/ G2 phases and the unparalleled efficiency of c-NHEJ throughout the cell cycle, raise the intriguing question as to how far a surviving cell reaches after repairing the genome back to its pre-irradiation state. Indeed, there is evidence that the genomes of cells surviving radiation treatment harbor extensive genomic alterations. To directly investigate this possibility, we adopted next-generation sequencing (NGS) technologies and tested a normal human fibroblast cell line, 82-6 hTert, after exposure up to 6 Gy. Cells were irradiated and surviving colonies expanded and the cells frozen. Sequencing analysis using the Illumina sequencing platform and comparison with the unirradiated genome detected frequent genomic alterations in the six investigated radiation survivor clones, including translocations and large deletions. Translocations detected by this analysis and predicted to generate visible cytogenetic alterations were frequently (three out of five) confirmed using mFISH cytogenetic analysis. PCR analysis of selected deletions also confirmed seven of the ten examined. We conclude that cells surviving radiation exposure tolerate and pass to their progeny a wide spectrum of genomic alterations. This recognition needs to be integrated into the interpretation of biological results at all endpoints, as well as in the formulation of mathematical models of radiation action. NGS analysis of irradiated genomes promises to enhance molecular cytogenetics by increasing the spectrum of detectable genomic alterations and advance our understanding of key molecular radiobiological effects and the logic underpinning DSB repair. However, further developments in the technology will be required to harness its full potential.

Abstract Electrospinning has been widely used as a versatile technique to generate nanofibers of various materials. It is also helpful in teaching topics ranging from macromolecular chemistry to physics, safety, and sustainability at various levels of difficulty and student involvement. Simple and safe hands-on experiments/manual assays can be realized for less than 30 euros to demonstrate polymer viscosity and nanofiber alignment and solubility. Students can further study (super)hydrophobicity and even upcycle packaging waste into useful filter materials but also improve the electrospinning setup from a manual assay to an inexpensive Arduino-based 3D printed research platform. Alternatively, the latter can be used for teacher demonstrations of more challenging experiments that can also be easily done using a commercial syringe-pump.

Abstract The synergistic combination of various sorbitol-based organogelators with polyolefins allows the preparation of porous support structures for immobilized phase change materials (PCMs). Using a PCM as a solvent for the preparation leads to dimensionally stable composite materials with extremely high loading rates and low leakage of PCMs. Detailed investigations were performed on the kind of polyolefin support and its mass fraction concentration in the PCM, the temperature-dependent softening and failure under superimposed load, the efficiency of heat transport and the retention capacity over several melting/solidification cycles in various measurement setups. In particular, paraffin wax in combination with 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol (TBPMN) and ultrahigh molecular weight polyethylene (UHMWPE) showed the best results in terms of high dimensional stability, low leakage, excellent processability and competitive heat capacity. The herein-established one-step preparation method saves time and energy compared to the loading of pre-formed porous supports and improves application-related properties at the same time.

Abstract The aim of this chapter is to address the impact of formal and informal institutions on women’s entrepreneurship and to extend our understanding of issues influencing women-owned businesses and women’s entrepreneurship in the context of a transition economy, such as Georgia. Our work specifically addresses formal institutions, such as governmental initiatives, financial institutions, and business-relevant education. It also addresses informal institutions, such as women’s role in society, the use of informal networks of connections and acquaintances, and gift-giving practices. Drawing on results from an online focus group discussion with women entrepreneurs in Georgia, we provide initial insights into the critical constraints and supporting factors that local women entrepreneurs experience. Based on the interrelation of institutions and women’s entrepreneurship, we conclude that changes in formal institutions do not lead directly to changing informal institutions. Due to the lack of trust in formal institutions, women entrepreneurs are more likely to look for business development solutions outside the official frames, including illegal or unethical means of survival. Nevertheless, increased opportunities – induced by specific entrepreneurship policies and programs – encourage women to enter entrepreneurship. In addition to this, entrepreneurship enables women in Georgia to overcome gender discrimination issues, which is more prevalent in employment relationships in the local labor market than in entrepreneurial activities.